Gomerged Document 8

MINISTRY USE ONLY

Place Personal Education Number (PEN) here.

© 2002 Ministry of Education

MINISTRY USE ONLY


MINISTRY USE ONLY

Biology 12

AUGUST 2002

Course Code = BI

Student Instructions

1. Place the stickers with your PersonalEducation Number (PEN) in the allottedspaces above. Under no circumstance isyour name or identification, other thanyour Personal Education Number, toappear on this booklet.

2. Ensure that in addition to this examinationbooklet, you have an ExaminationResponse Form. Follow the directions onthe front of the Response Form.

3. Disqualification from the examination willresult if you bring books, paper, notes orunauthorized electronic devices into theexamination room.

4. When instructed to open this booklet, checkthe numbering of the pages to ensure thatthey are numbered in sequence from pageone to the last page, which is identified by

END OF EXAMINATION .

5. At the end of the examination, place yourResponse Form inside the front cover of thisbooklet and return the booklet and yourResponse Form to the supervisor.

Question 1:

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Question 3:

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Question 11:

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BIOLOGY 12

AUGUST 2002

COURSE CODE = BI

GENERAL INSTRUCTIONS

1. Electronic devices, including dictionaries and pagers, are not permitted in theexamination room.

2. All multiple-choice answers must be entered on the Response Form using anHB pencil. Multiple-choice answers entered in this examination booklet will notbe marked.

3. For each of the written-response questions, write your answer in ink unlessotherwise instructed in the space provided in this booklet.

4. Ensure that you use language and content appropriate to the purpose and audienceof this examination. Failure to comply may result in your paper being awarded azero.

5. This examination is designed to be completed in two hours. Students may,however, take up to 30 minutes of additional time to finish.

BIOLOGY 12 PROVINCIAL EXAMINATION

ValueSuggested

Time1. This examination consists of two parts:

PART A: 50 multiple-choice questions 50 45

PART B: 11 written-response questions 50 75

Total: 100 marks 120 minutes

THIS PAGE INTENTIONALLY BLANK

OVER- 1 -

PART A: MULTIPLE CHOICE

Value: 50 marks Suggested Time: 45 minutes

INSTRUCTIONS: For each question, select the best answer and record your choice on the ResponseForm provided. Using an HB pencil, completely fill in the circle that has the lettercorresponding to your answer.

1. Most of the protein produced by a cell is manufactured at the

A. nucleus.B. vacuoles.C. rough endoplasmic reticulum.D. smooth endoplasmic reticulum.

2. Which structure is responsible for endocytosis?

A. nucleolusB. Golgi bodyC. cell membraneD. endoplasmic reticulum

Use the following list to answer question 3.

• DNA• pepsin• maltose• water molecules

3. How many of the substances above have hydrogen bonding?

A. 1B. 2C. 3D. 4

- 2 -

4. What is the function of a buffer in the bloodstream?

A. destroy virusesB. transport oxygenC. initiate blood clottingD. keep the pH at a constant level

5. Which of the following molecules is used in the synthesis of lipids?

A.

H N C C

H

R OH

O B.

H

H

H

OH

OH

OH

C

C

C

H

H

C.

H

HO

H – C – OH

H

HOH

O

OH

H

H

OH

H D.P

N

N

________________________________________________

6. Two water molecules are produced by the union of glucose molecules during dehydrationsynthesis. What is the new molecule that is formed?

A. a dipeptideB. a disaccharideC. a polysaccharideD. a monosaccharide

7. How do saturated fats differ from unsaturated fats?

A. They are water soluble.B. They contain cholesterol.C. They form straight chains.D. Their hydrogen-to-carbon ratio is larger.

OVER- 3 -

8. Which of the following molecules can be converted into a hormone that determines male sexcharacteristics?

A.CH3

CH3

B.C C C C C C C C C C C C C C C C C CH

H

H

H

H

H H H

H

H H H

H

H H H

H

H

H

H

H

H

H

H

H

H

H

H

H

O

OH

C.

CH2

CH3(CH2)16 CH2C O

O

CH3(CH2)16 CHC O

O

CH3(CH2)16 C O

O

D.H

C C N

O R H

C N CH

R H O

HC C N

O R H

C N CH

R H O

HC C N

O R H

C N CH

R H O

HC C N

O R H

C N CH

R H O

HC C

O R

C NH

R H

- 4 -

Use the following diagram to answer question 9.

H

C CN

O

HO

X

C HH

H

C HH

H

H

9. The section labelled X is the

A. acid.B. amine.C. R-group.D. bicarbonate ion.

________________________________________________

10. What is combined genetic material from two different organisms called?

A. viral DNAB. ribosomal RNAC. transcription RNAD. recombinant DNA

11. The term codon is used to describe a sequence of bases in

A. DNA.B. rRNA.C. tRNA.D. mRNA.

OVER- 5 -

Use the following graph to answer question 12.

Production of a particular mRNAand its matched polypeptide product

time

W X Y Z

amountsynthesized

mRNApolypeptide

12. At which of the following times is transcription, but not translation, occurring?

A. WB. XC. YD. Z

________________________________________________

13. What term is used to describe the spread of cancer cells through the circulatory system tonew locations?

A. anaplasiaB. metastasisC. vascularizationD. contact inhibition

14. Which of the following is a function of an oncogene?

A. fighting diseaseB. inhibiting protein synthesisC. becoming a proto-oncogeneD. causing a cell to become cancerous

- 6 -

15. Which molecules function as pores and carriers in a cell membrane?

A. lipidsB. proteinsC. nucleotidesD. carbohydrates

16. By what process do lipid-soluble molecules and gases cross the cell membrane?

A. osmosisB. diffusionC. pinocytosisD. active transport


17. The diagram shows a white blood cell ingesting a bacterium. By what process does thebacterium enter the white blood cell?

A. pinocytosisB. phagocytosisC. active transportD. facilitated transport

________________________________________________

18. An enzyme acts as a catalyst because it is capable of

A. slowing down many different reactions.B. acting as a reactant in a chemical reaction.C. lowering the energy required for the reaction to occur.D. providing hydrogen ions and electrons for a chemical reaction.

OVER- 7 -


W X Y ZE3E2E1

19. In the series of enzyme reactions shown above, product Z is able to occupy the active site ofenzyme E2. Product Z can therefore first inhibit the production of

A. X

B. E2

C. Y

D. Z


X

20. Secretions from gland X cause decreased

A. body temperature.B. oxygen uptake in cells.C. production of carbon dioxide.D. concentration of blood glucose.

- 8 -


X

21. In the diagram above, molecule X is acting as

A. a substrate.B. an enzyme.C. a coenzyme.D. a competitive inhibitor.

OVER- 9 -

Use the following diagram to answer questions 22 and 23.

Y

X

ZW

22. What is the structure labelled W?

A. liverB. pancreasC. appendixD. duodenum

23. Malfunctioning of which structure would result in higher than normal levels of glucosein the blood?

A. WB. XC. YD. Z

________________________________________________

24. Which digestive structure has the greatest influence on blood volume?

A. colonB. stomachC. pancreasD. small intestine

- 10 -

25. Which structure is not correctly matched with an enzyme it produces?

StructureEnzyme

Produced

A. stomach trypsin

B. pancreas amylase

C. small intestine peptidase

D. salivary glands amylase


W X

Y

Z

26. An individual has an abnormally high level of fat in the feces. Which structure could bemalfunctioning?

A. WB. XC. YD. Z

OVER- 11 -

27. A student ingests a large amount of sugar at time X. Which of the following graphs correctlydepicts blood glucose concentration in the hepatic vein?

A.

time

blood glucoseconcentration

normal

X

B.

time


normal

X

C.

time


normal

X

D.

time


normal

X

________________________________________________

28. Which structure allows blood to pass between the two atria of a fetal heart?

A. arterial ductB. venous ductC. oval openingD. umbilical artery

29. In which of the following can DNA replication occur?

A. plateletsB. antibodiesC. red blood cellsD. white blood cells

- 12 -

30. What is produced in response to viruses entering the body?

A. antigensB. plateletsC. antibodiesD. red blood cells

31. The pleural membranes surround

A. the lungs.B. the trachea.C. each alveolus.D. the diaphragm.

32. Where does external respiration occur?

A. larynxB. alveoliC. tracheaD. bronchi

33. During the expiration of air, the diaphragm moves

A. up, resulting in a decrease in pressure in the thoracic cavity.B. up, resulting in an increase in pressure in the thoracic cavity.C. down, resulting in a decrease in pressure in the thoracic cavity.D. down, resulting in an increase in pressure in the thoracic cavity.

OVER- 13 -


X

34. What is the function of the neuron above?

A. to take an impulse to an interneuronB. to send sensory information to the central nervous systemC. to take an impulse from a motor neuron to a sensory neuronD. to carry a nerve impulse away from the central nervous system

35. What is the structure labelled X?

A. synapseB. cell bodyC. node of RanvierD. myelinated dendrite

________________________________________________

36. Why can an impulse travelling along an axon not reverse its direction?

A. The myelin sheath will only permit one-way travel of an impulse.

B. Sodium gates remain closed until the impulse reaches the synapse.

C. The threshold required to create an action potential behind the impulse is increased.

D. The sodium-potassium pump has not restored the resting potential immediately behindthe action potential.

37. If potassium ions could not diffuse out of the axon, which of the following would result?

A. Repolarization would not occur.B. A neurotransmitter would be released.C. The length of the recovery phase would be reduced.D. The frequency of action potentials would be increased.

- 14 -

38. Which division of the nervous system is used to stimulate digestion after a“fight or flight” response?

A. centralB. somaticC. sympatheticD. parasympathetic


X

39. What is the part of the brain labelled X?

A. thalamusB. hypothalamusC. corpus callosumD. medulla oblongata

________________________________________________

40. Which organ excretes urea and some salts?

A. lungB. colonC. kidneyD. gallbladder

OVER- 15 -


X

Y


A. ureterB. urethraC. renal pelvisD. urinary bladder

42. Which of the following is not a function of structure Y?

A. control of blood pHB. production of glycogenC. excretion of histaminesD. maintenance of blood volume

________________________________________________

43. What is the correct order of the processes which would modify blood plasma as it passesthrough the nephron?

A. filtration → tubular excretion → selective reabsorption → reabsorption of waterB. filtration → selective reabsorption → reabsorption of water → tubular excretionC. selective reabsorption → reabsorption of water → filtration → tubular excretionD. selective reabsorption → filtration → tubular excretion → reabsorption of water

- 16 -


percentageof water

Percentage of water in the filtratewithin various parts of a nephron

W

X

Y

Z

structures in the nephron

44. Which structure is most likely the collecting duct?

A. WB. XC. YD. Z

________________________________________________

45. Why is the loop of Henle important to the maintenance of blood volume?

A. It reabsorbs glucose.B. It synthesizes blood proteins.C. It adjusts the pH of the urine.D. It produces a hypertonic renal medulla.

OVER- 17 -


X

time (h)

concentrationof solutes in

the urine

46. The concentration of solutes in the urine was measured over a one-day period. What mighthave caused the change that occurred at time X?

A. The blood became more acidic.B. Excess sodium ions were excreted.C. The secretion of ADH was inhibited.D. Aldosterone production was stimulated.

________________________________________________

47. Where do sperm mature?

A. epididymisB. interstitial cellsC. seminal vesiclesD. ductus (vas) deferens

48. Where is follicle-stimulating hormone (FSH) produced?

A. follicleB. hypothalamusC. corpus luteumD. anterior pituitary

- 18 -

49. Which of the following events results from positive feedback on the hypothalamus betweendays 1 to 13 of the menstrual cycle?

A. ovulationB. implantationC. menstruationD. thickening of the endometrium

50. What is one result of an embryo failing to implant in the endometrium?

A. the degeneration of the corpus luteumB. an increased production of progesteroneC. the release of human chorionic gonadotropin (HCG)D. a decreased production of follicle-stimulating hormone (FSH)

This is the end of the multiple-choice section.Answer the remaining questions directly in this examination booklet.

OVER- 19 -

PART B: WRITTEN RESPONSE


INSTRUCTIONS: 1. Use a pen for this part of the examination unless otherwise instructed.

2. Write your answers in the space below the questions.

3. Organization and planning space has been incorporated into the space allowedfor answering each question.

4. You may not need all of the space provided to answer each question.

Use the following diagrams to answer question 1.

W

X Y

Z

1. Describe how structures W, X, Y and Z work together. (4 marks)

- 20 -


P P

P P

P P

P P

P P

S ST A

A TS S

G CS S

T AS S

C GS S

G CS S

P P

2. a) Describe replication of this molecule. (3 marks)

OVER- 21 -

b) What is the role of this molecule in determining the structure of a protein? (1 mark)

c) Reading top to bottom, determine the mRNA sequence that would be transcribed fromthe left-hand strand of this molecule. (1 mark)

d) Give the anticodons that are complementary to this mRNA sequence. (1 mark)

- 22 -

3. a) Why do oxygen molecules enter a cell at a different rate than protein molecules. (1 mark)

b) State two ways to increase the rate of oxygen movement into a cell. (2 marks)

i)

ii)

OVER- 23 -


4. Explain how the structure above is well-suited for its function. (5 marks)

- 24 -

Use the following list to answer question 5 a).

• aorta• renal vein• renal artery• subclavian vein• subclavian artery• pulmonary artery• anterior vena cava

5. a) Choose the vessel names from the list above to fill in the boxes that describe the pathof blood from the arm to the kidney. (Use only one term per box. Not all of the termswill be used.) (4 marks)

arm

right side of heart

left sideof heartlungs

kidney

OVER- 25 -

b) Give one function of each of the following. (4 marks: 1 mark each)

carotid arteries:

lymph veins:

antibodies:

chordae tendineae:

- 26 -


X Y

6. Describe what happens to the concentrations of oxygen, carbon dioxide and nutrients inthe blood as it moves between points X and Y in the skin. (3 marks)

OVER- 27 -

7. Explain why the breathing rate increases in someone who is exercising strenuously. (3 marks)

- 28 -

8. Describe the sequence of events required for a nerve impulse to cross a synapse.(You may use a labelled diagram as part of your answer. You may use a pencilto draw your diagram.) (5 marks)

OVER- 29 -


X

Y

Z

9. Give one function of each of the following structures. (3 marks: 1 mark each)

Structure X:

Structure Y:

Structure Z:

- 30 -


X

Y

10. a) Identify structure X. (1 mark)

b) Describe the process that occurs between X and Y. (2 marks)

c) Identify two components of blood that cannot move into the filtrate undernormal conditions. (2 marks)

i)

ii)

- 31 -

11. a) Give three characteristics of semen and describe how each of these characteristicsfacilitates the function of semen. (3 marks)

i)

ii)

iii)

b) What would result if luteinizing hormone (LH) was not secreted in the male? (2 marks)

END OF EXAMINATION

MINISTRY USE ONLY



MINISTRY USE ONLY


MINISTRY USE ONLY

Biology 12

JUNE 2002

Course Code = BI








Question 1:

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Question 6:

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(7)

Question 10:

10. .

(3)

BIOLOGY 12

JUNE 2002

COURSE CODE = BI


ValueSuggested





OVER- 1 -





X

Y

1. The structure labelled X is the

A. ribosome.B. Golgi body.C. mitochondrion.D. endoplasmic reticulum.

2. The function of the structure labelled Y is

A. phagocytosis.B. steroid synthesis.C. cellular respiration.D. selective re-absorption.

- 2 -

3. Which of the following cells of equal volume would be the most efficient at absorbing nutrientsas well as synthesizing and secreting a product?

A. B.

C. D.

________________________________________________

4. The products of reactions at the rough endoplasmic reticulum are transported in

A. cilia.B. vesicles.C. nucleoli.D. mitochondria.

5. Translation occurs at which of the following organelles?

A. nucleusB. vacuoleC. ribosomeD. nucleolus

OVER- 3 -


+

H

HO

CH2OH

H

H

OH

O

OH

H

H

OH

H

HO

CH2OH

H

H

OH

O

OH

H

H

OH

H

HO

CH2OH

H

H

OH

O

OH

H

H H

CH2OH

H

H

OH

O

OH

H

H

OH

O + X

6. In the reaction above, what is molecule X?

A. waterB. an acidC. glucoseD. an enzyme

________________________________________________

7. Which of the following refers to primary protein structure?

A. the helical shape of the proteinB. the linear sequence of amino acidsC. several protein molecules joined togetherD. the three-dimensional shape of the molecule

8. Which of the following is not a component of a nucleotide?

A. sugarB. phospholipidC. phosphate groupD. nitrogenous base

9. Which of the following correctly describes the number of bases in DNA?

A. Adenine equals cytosine.B. Thymine equals guanine.C. Adenine and thymine equal guanine and cytosine.D. Adenine and cytosine equal thymine and guanine.

- 4 -

10. DNA from a wheat plant contains a gene that codes for the production of a bacterial enzyme.This is an example of

A. initiation.B. promotion.C. transfer RNA.D. recombinant DNA.

11. Which of the following correctly contrasts RNA and DNA?

RNA DNA

A. sugar deoxyribose ribose

B. structure single-stranded double-stranded

C. location cytoplasm nucleus and cytoplasm

D. shape helix linear

12. Which of the following is a characteristic of cancerous cells?

A. flat shapeB. undifferentiatedC. large amount of cytoplasmD. increased contact inhibition

13. Which of the following provides more oxygen to cancer cells?

A. metastasisB. promotionC. vascularizationD. abnormal nuclei

OVER- 5 -

14. A virus can cause carcinogenesis in a human cell by

A. becoming a cancer cell.B. inhibiting transcription.C. introducing an oncogene.D. converting oncogenes into proto-oncogenes.

15. According to the fluid-mosaic membrane model, phospholipids

A. form a single layer.B. have the consistency of light oil.C. actively transport potassium ions.D. are only found on the outer layer of the membrane.

________________________________________________

16. Four tissue samples were placed in four test tubes, each containing a sucrose solution ofa different concentration. After a period of time, the final mass of each tissue samplewas recorded.

TestTube

Initial Massof Tissue

(g)

Final Massof Tissue

(g)

1 1.4 1.4

2 1.9 1.8

3 1.3 1.8

4 1.7 1.7

Given the results, which of the test tubes has a solution that is hypotonic to the tissue sample?

A. 1B. 2C. 3D. 4

- 6 -

17. The function of the gallbladder is to

A. store bile.B. store lipase.C. produce urea.D. produce trypsin.

18. Starting in the esophagus, how many sphincters will an indigestible fibre molecule passthrough on its way to the small intestine?

A. oneB. twoC. threeD. five

19. Which of the following enzymes produces a product that cannot be absorbed into the body?

A. lipaseB. maltaseC. amylaseD. nuclease

OVER- 7 -


W

X

Y

Z

20. Which letter indicates the area from which the products of lipid digestion are transportedthroughout the body?

A. WB. XC. YD. Z

________________________________________________

21. Which of the following substances used by the body is produced by E-coli living in thedigestive system?

A. mineralsB. vitaminsC. fatty acidsD. polysaccharides

- 8 -

22. A function of an artery is to carry

A. blood to the small intestine.B. blood from the head to the heart.C. metabolic wastes away from the liver.D. oxygenated blood from the lungs to the heart.

23. The blood vessels that carry blood to and from the head are the

A. aorta and pulmonary vein.B. coronary artery and hepatic vein.C. carotid arteries and jugular veins.D. anterior vena cava and pulmonary artery.

OVER- 9 -


W

Y

X

Z

24. Which of the following represents the iliac vein?

A. WB. XC. YD. Z

________________________________________________

25. Which two structures in the fetal circulatory system allow blood to bypass the lungs?

A. venous duct and oval openingB. oval opening and arterial ductC. pulmonary vein and arterial ductD. umbilical artery and pulmonary vein

- 10 -

26. The lymphatic system consists of

A. vessels and valves.B. AV and semilunar valves.C. the pulmonary artery and the arterial duct.D. the umbilical artery and the pulmonary vein.


27. What is the name of the blood components shown in the diagram?

A. plateletsB. red blood cellsC. plasma proteinsD. white blood cells

OVER- 11 -


V

W

XY

Z

28. In which of the labelled structures would the highest blood pressure be measured?

A. VB. WC. XD. Y

29. Which of the following correctly identifies structure Z in the diagram above and thecomposition of blood it contains?

StructureZ

Compositionof Blood

A. vein high concentration of oxyhemoglobin

B. vein low concentration of oxyhemoglobin

C. artery high concentration of reduced hemoglobin

D. artery low concentration of reduced hemoglobin

________________________________________________

30. As the blood moves through capillary beds from arteriole to venule, the osmotic pressurein the blood D E L E T E D

A. increases.B. decreases.C. is lost entirely.D. stays the same.

- 12 -

31. Which of the following surrounds the lungs and the thoracic cavity and functions to reducefriction during inhalation and exhalation?

A. ciliaB. alveoliC. diaphragmD. pleural membranes


W

X

Y

Z

32. The bronchus is labelled

A. W.B. X.C. Y.D. Z.

33. The structure labelled Z functions to

A. filter dust from the air.B. exchange oxygen and carbon dioxide.C. move blood into the inferior vena cava.D. change the volume of the thoracic cavity.

OVER- 13 -

Use the following information to answer question 34.

1. The diaphragm flattens.

2. The rib cage moves down and in.

3. The volume of the thoracic cavity increases.

4. The medulla oblongata signals the rib muscles to contract.

34. Which sequence correctly shows the order of events during breathing?

A. 1, 2, 4, 3B. 2, 4, 3, 1C. 3, 1, 2, 4D. 4, 1, 3, 2

________________________________________________

35. A small amount of carbon dioxide is transported in the pulmonary artery as

A. bicarbonate ion.B. carbonic anhydrase.C. reduced hemoglobin.D. carbaminohemoglobin.

36. Which of the following carries a nerve impulse toward the spinal cord?

A. interneuronB. synaptic cleftC. motor neuronD. sensory neuron

- 14 -


membrane potential(millivolts)

time (milliseconds)

0

40+

65–

X Y

37. Which of the following events is causing the change within the neuron betweentime X and time Y?

A. Sodium ions are moving into the axon.B. Sodium ions are moving out of the axon.C. Potassium ions are moving out of the axon.D. Large, organic, negative ions are moving into the axon.

________________________________________________

38. Movement of which of the following ions causes depolarization?

A. sodiumB. calciumC. hydrogenD. potassium

39. Which substance causes the microfilaments to contract and pull the synaptic vesicles to thepresynaptic membrane?

A. sodium ionsB. calcium ionsC. noradrenalinD. acetylcholine

OVER- 15 -


YX


A. pituitary.B. cerebellum.C. hypothalamus.D. medulla oblongata.

41. Increased activity in structures X and Y is associated with which of the following?

A. rebuilding of the endometriumB. decreased coordination of skeletal muscleC. contraction of smooth muscle in the intestinesD. reabsorption of neurotransmitters in the synaptic cleft

________________________________________________

42. What is the pathway for urine leaving the body?

A. collecting duct → renal pelvis → bladder → ureterB. collecting duct → renal pelvis → ureter → bladderC. renal pelvis → collecting duct → ureter → bladderD. renal pelvis → bladder → ureter → collecting duct

- 16 -

43. Which of the following is less concentrated in blood plasma than it is in urine?

A. ureaB. insulinC. glucoseD. carbon dioxide


Water lost from the body (mL per day)on two different days

From Day 1 Day 2

Evaporation 900 1 200

Urine 1 500 1 200

Feces 100 100

44. Homeostasis is maintained on day 2 by a hormone that is produced in the

A. hypothalamus and acts on the collecting duct.B. adrenal cortex and acts on the collecting duct.C. posterior pituitary and acts on the loop of Henle.D. anterior pituitary and acts on the distal convoluted tubule.

________________________________________________

45. What is the function of the mid-piece of the sperm?

A. to propel the spermB. to protect the spermC. to produce ATP energyD. to carry genetic material

OVER- 17 -


Z

X

Y

W

46. Structure W contains the

A. cervix.B. oviduct.C. endometrium.D. corpus luteum.

47. At which of the labelled structures is human chorionic gonadotropin (HCG) released?

A. WB. XC. YD. Z

________________________________________________

48. Which hormone is released by the anterior pituitary that triggers the production ofegg or sperm cells?

A. estrogenB. progesteroneC. luteinizing hormone (LH)D. follicle-stimulating hormone (FSH)

- 18 -

49. On which day of a typical 28-day menstrual cycle will luteinizing hormone (LH) be thehighest?

A. day 2B. day 7C. day 13D. day 28

50. Which of the following substances stimulates uterine contractions?

A. estrogen and calciumB. oxytocin and prostaglandinsC. progesterone and human chorionic gonadotropin (HCG)D. acrosomal enzymes and follicle-stimulating hormone (FSH)


OVER- 19 -







- 20 -


C

OH

H

NH

H

C

R

OX

Y

1. a) Identify each of the following parts of the molecule. (2 marks: 1 mark each)

Part X:

Part Y:

b) State two different polymers that are synthesized from the molecule and give afunction of each. (4 marks: 1 mark each for polymer; 1 mark each for function)

Polymer Function

OVER- 21 -

2. Describe how the following are related in terms of their function in protein synthesis.

DNA and mRNA: (2 marks)

tRNA and ribosomes: (2 marks)

- 22 -

3. The cells of the thyroid gland are able to take in iodine atoms and may contain iodineconcentrations up to 25 times that of the surrounding tissue fluid. In an experiment designed tostudy factors affecting the rate of iodine intake, thyroid cells were cultured and placed in a mediumcontaining normal blood concentrations of iodine. Temperature and glucose concentrations werevaried and the effects recorded. The results of the study are shown in the table below.

A

B

0.20

0.01

0.20

38

38

60

22

12

8

SampleGlucose

Concentration(%)

Temperature(°C)

Increase in IodineConcentration

(X)

normal conditions

a) Explain the observed results for sample A. (2 marks)

b) Explain the observed results for sample B. (2 marks)

c) Explain how the movement of amino acids into the cells would be affected by theconditions in sample B. (2 marks)

OVER- 23 -

4. Describe the pH in each of the following regions along the digestive tract. Identify thesecretion which determines the pH of the region and give the source of the secretion.

stomach: (3 marks)

pH:

secretion:

source of secretion:

small intestine: (3 marks)

pH:

secretion:

source of secretion:

- 24 -

5. For each of the following processes, describe how the small intestine functions todigest food and absorb nutrients.

digestion: (3 marks)

absorption: (2 marks)

OVER- 25 -


6. a) Identify the type of blood vessel shown in the diagram. (1 mark)

b) State two functions of the blood vessel in the diagram. (2 marks)

i)

ii)

- 26 -

7. Place the correct number for each of the following characteristics in the appropriatebox at the locations in the diagram. (Only put one number per box. Not all ofthe characteristics will be used.) (4 marks)

1. has stretch receptors2. prevents collapse of the lungs3. filters, warms and moistens air4. stops food from entering the lungs5. allows food and air to pass through6. has cilia, cartilaginous rings and mucous membranes

OVER- 27 -

8. a) In what type of situation does the sympathetic nervous system respond? (1 mark)

b) What division is the sympathetic system part of? (1 mark)

c) State four effects on the body when the sympathetic nervous system is active. (4 marks)

i)

ii)

iii)

iv)

- 28 -

Use the following diagram to answer question 9 a) and b).

X

Y

Z

9. a) Identify the following structures. (2 marks: 1 mark each)

Structure X:

Structure Z:

b) In an experiment, fluids were removed at point X and at point Y and the compositionof each sample was analyzed. Describe three ways in which the fluid obtained atpoint X is different from the fluid obtained at point Y. (3 marks)

i)

ii)

iii)

OVER- 29 -

c) Explain how an increase in blood pressure from 120/80 to 160/100 would increasethe volume of urine produced. (2 marks)

- 30 -

10. Give one function for each of the following substances found in seminal fluid.(3 marks: 1 mark each)

fructose

prostaglandins

alkaline (basic) fluid

Substance Function

END OF EXAMINATION

MINISTRY USE ONLY



MINISTRY USE ONLY


MINISTRY USE ONLY

Biology 12

JANUARY 2002

Course Code = BI








Question 1:

1. .

(4)

Question 2:

2. .

(4)

Question 3:

3. .

(6)

Question 4:

4. .

(6)

Question 5:

5. .

(6)

Question 6:

6. .

(4)

Question 7:

7. .

(5)

Question 8:

8. .

(2)

Question 9:

9. .

(7)

Question 10:

10. .

(6)

BIOLOGY 12

JANUARY 2002

COURSE CODE = BI


ValueSuggested





OVER- 1 -





W

X

Y

Z

1. A protein being packaged and modified for export would be found in

A. W.B. X.C. Y.D. Z.

- 2 -


X

2. Structure X is composed of molecules produced by the

A. nucleus.B. vesicles.C. nucleolus.D. lysosomes.

________________________________________________

3. Consider the functions of the following:

heart muscle cells

sperm

cells lining the proximalconvoluted tubules

heart muscle cells

In order for these metabolically active cells to carry out their functions effectively, they requirelarge numbers of which organelle?

A. ribosomesB. lysosomesC. Golgi bodiesD. mitochondria

OVER- 3 -


• solvent• catalyst• lubricant• temperature regulator

4. How many of the above are roles of water in the body?

A. 1B. 2C. 3D. 4


synthesis+H N C

O

OH H

H H

N C C

O

OHRR

H H

+ H2OH N C C N C C

C

OHR R

H H O H H

C

5. At which of the following organelles would the reaction shown take place?

A. nucleusB. ribosomeC. lysosomeD. smooth endoplasmic reticulum

________________________________________________

6. Which of the following types of molecules does not have to be digested before being absorbed?

A. maltoseB. peptidesC. amino acidsD. nucleic acid

- 4 -

7. Which of the following is the empirical formula for glucose?

A. CHO

B. CH2O

C. CH2O2

D. C2HO2


OOO

O

O OOO

OO

OO

OO

OO

OO

O

8. The molecule above would likely be found in a

A. vacuole.B. liver cell.C. mitochondria.D. plant cell wall.

________________________________________________

9. Hemoglobin and antibodies are all composed of

A. lipids.B. proteins.C. carbohydrates.D. polysaccharides.

10. Which of the following statements correctly describes DNA?

A. Guanine bonds to cytosine and adenine bonds to uracil.B. Peptide bonds are found between guanine and cytosine.C. Hydrogen bonds are found between thymine and guanine.D. Nucleotides are composed of a sugar, a phosphate and a base.

OVER- 5 -

11. DNA replication produces

A. two different strands of RNA.B. two identical molecules of DNA.C. an mRNA strand that has copied a gene.D. a parent DNA strand and a daughter tRNA strand.

12. Which term refers to cells which grow and reproduce in a disorganized anduncontrolled manner?

A. anaplasiaB. metastasisC. promotionD. vascularization

13. A portion of DNA which has been changed by an initiator becomes

A. vascularized.B. an oncogene.C. undifferentiated.D. a proto-oncogene.


site 1 site 2 site 3 site 4

a segment of anormal DNA strand T A C A T G C A T G G A C A C C A T G A G C A

resultingoncogene A T G G A C C A T T A A G C A

a virus carries thissegment of DNA C C A T T A A G

14. At which site in the normal DNA strand can the viral strand be inserted to initiatecarcinogenesis?

A. site 1B. site 2C. site 3D. site 4

- 6 -


X

energy

15. What is a function of the structure labelled X in the process shown above?

A. to engulf bacteria by phagocytosisB. to transport lipid-soluble moleculesC. to pump sodium ions out of neuronsD. to increase the rate of diffusion of carbon dioxide

________________________________________________

16. The reactant in an enzyme-catalyzed reaction can also be called

A. a complex.B. a substrate.C. an enzyme.D. a coenzyme.

17. Overall metabolic rate would increase with increased secretion of

A. trypsin.B. thyroxin.C. nuclease.D. acetylcholine.

OVER- 7 -

18. Which of the following can be used to determine the rate of enzyme-catalyzed reactions?

A. increase in activation energyB. increase in product over timeC. increase in enzyme over timeD. increase in coenzyme over time

19. When the active site of an enzyme is denatured,

A. substrates cannot be formed.B. a quaternary structure is achieved.C. the activation energy is decreased.D. an enzyme-substrate complex cannot be formed.

20. Vitamins function as

A. enzymes.B. coenzymes.C. emulsifiers.D. competitive inhibitors.

- 8 -


X


A. pharynx.B. epiglottis.C. esophagus.D. duodenum.

________________________________________________

22. A bacterial infection inhibits the absorption of water in the digestive system leading todehydration. The infection is located in the

A. liver.B. stomach.C. duodenum.D. large intestine.

OVER- 9 -

23. Which of the following organs is malfunctioning when the concentration of nitrogenous wastesin the blood increases?

A. kidneyB. stomachC. pancreasD. small intestine

24. Insulin secretion is increased when the level of

A. sodium in the blood is low.B. sodium in the blood is high.C. glucose in the blood is low.D. glucose in the blood is high.

25. Bile acts as an emulsifier by

A. increasing the surface area of lipids.B. removing hydrogen atoms from lipids.C. breaking the bonds between fatty acids and glycerol.D. converting unsaturated fatty acids to saturated fatty acids.

26. The liver makes blood plasma hypertonic to the fluid surrounding tissues by

A. breaking down hemoglobin.B. storing glucose as glycogen.C. making plasma proteins from amino acids.D. detoxifying and removing poisonous substances.

- 10 -


X

27. The structure above is found in the

A. liver.B. stomach.C. renal medulla.D. small intestine.

28. Structure X is specialized to

A. absorb fats.B. repackage glucose.C. transport amino acids.D. secrete hydrochloric acid.

OVER- 11 -


29. The blood vessel shown in the diagram is classified as

A. a vein.B. an artery.C. a capillary.D. an arteriole.

- 12 -


X

30. The artery labelled X is the

A. aorta.B. carotid.C. coronary.D. subclavian.

________________________________________________

31. A blood clot forms in the hepatic vein but breaks off and lodges in the next capillary bed itencounters. Where would it be found?

A. liverB. brainC. lungsD. small intestine

OVER- 13 -


32. The stages in the cardiac cycle shown by the diagrams are

A. atrial systole followed by ventricular systole.B. atrial systole followed by ventricular diastole.C. atrial diastole followed by ventricular systole.D. atrial diastole followed by ventricular diastole.

________________________________________________

33. Which of the following trap particles and move them up the trachea?

A. villi and mucusB. mucus and ciliaC. alveoli and villiD. cilia and alveoli

34. Speech sounds are made when air moves through the

A. cilia.B. larynx.C. pharynx.D. diaphragm.

35. What occurs when the diaphragm relaxes and becomes dome shaped?

A. The rib muscles relax, thoracic cavity volume increases and exhalation occurs.B. The rib muscles relax, thoracic cavity volume decreases and exhalation occurs.C. The rib muscles contract, thoracic cavity volume increases and inhalation occurs.D. The rib muscles contract, thoracic cavity volume decreases and inhalation occurs.

- 14 -

36. During external respiration, the concentration of which of the following increases in the blood?

A. ATPB. hemoglobinC. oxyhemoglobinD. reduced hemoglobin

37. Which substance is transported as reduced hemoglobin in the blood?

A. waterB. oxygenC. hydrogen ionsD. carbon dioxide

38. Hemoglobin in the umbilical artery carries less of which substance thanhemoglobin in the umbilical vein?

A. oxygenB. hydrogen ionsC. carbon dioxideD. bicarbonate ions

OVER- 15 -

Use the following graph to answer questions 39 and 40.

Y


time(milliseconds)

–65

0

+40

W X

39. The time period between W and X is called

A. repolarization.B. depolarization.C. the recovery period.D. the resting potential.

40. Which of the following are characteristics of the neuron at time Y? D E L E T E D

A. positively charged axoplasm and diffusion of sodium ions into the axoplasmB. positively charged axoplasm and diffusion of potassium ions into the axoplasmC. negatively charged axoplasm and diffusion of sodium ions out of the axoplasmD. negatively charged axoplasm and diffusion of potassium ions out of the axoplasm

________________________________________________

41. If a person’s ability to integrate information from both hemispheres of the brain is impaired,the portion of the brain most likely affected is the

A. pituitary.B. thalamus.C. cerebellum.D. corpus callosum.

- 16 -

42. The collecting ducts are located in which of the following structures?

A. ureterB. urethraC. renal pelvisD. renal medulla

43. Active transport of glucose into the blood occurs in the

A. glomerulus.B. collecting duct.C. Bowman’s capsule.D. proximal convoluted tubule.

44. Damage to the glomerulus could lead to the presence of

A. excess glucose in the urine.B. red blood cells in the filtrate.C. an increase of urea in the renal cortex.D. a decrease of nitrogenous waste in the filtrate.

45. Which of the following structures responds to low sodium levels in the blood?

A. liverB. thyroidC. adrenalD. pancreas

46. Spermatogenesis occurs in the

A. interstitial cells.B. seminal vesicles.C. seminiferous tubules.D. ductus (vas) deferens.

OVER- 17 -

47. Which part of a sperm cell contains the enzymes that aid the penetration of an ovum?

A. tailB. headC. acrosomeD. mid-piece

48. Which hormone is responsible for increased musculature and body hair?

A. estrogenB. testosteroneC. follicle-stimulating hormone (FSH)D. human chorionic gonadotropin (HCG)


W

X

Y

Z

49. Which letter indicates the uterus?

A. WB. XC. YD. Z

- 18 -

Use the following graphs to answer question 50.

hormone levelsin plasma

days into cycle

1 14 28

hormone levelsin plasma

days into cycle

1 14 28

ovarianhormone levels

pituitaryhormone levels

W

X

Y

Z

50. Which letter represents levels of follicle-stimulating hormone during the ovarian anduterine cycles?

A. WB. XC. YD. Z


OVER- 19 -







1. a) Define recombinant DNA. (1 mark)

b) Give two uses of recombinant DNA. (2 marks)

i)

ii)

c) In which organelle of a human cell would recombinant DNA be found? (1 mark)

- 20 -


OVER- 21 -

2. Give a role of each of the following nucleic acids in the production of an enzyme.(4 marks: 1 mark each)

DNA:

mRNA:

rRNA:

tRNA:

- 22 -

3. In an experiment, 10 cubes of potato each weighing 10 grams and cut from the same potatowere placed in 10 different numbered beakers. Each beaker contained a different concentrationof sucrose solution as shown in the table below. After 24 hours, the potato cubes wereremoved, blotted dry and their weights entered into the data table.

BeakerConcentration

of Sucrose(%)

Weight ofPotato Cube

After 24 Hours(grams)

PercentChangein Mass

(%)

1 0.0 13.4 34

2 0.5 12.5 25

3 1.0 11.2 12

4 1.5 10.3 3

5 2.0 9.2 –8

6 2.5 8.5 –15

7 3.0 8.0 –20

8 3.5 7.7 –23

9 4.0 7.5 –25

10 4.5 7.4 –26

a) Why were all the pieces cut from the same potato? (1 mark)

OVER- 23 -

b) Graph the data that compares the concentration of sucrose to the percent change in mass.(2 marks: 1 mark for plotting points; 1 mark for drawing line)

10

20

30

0

–10

–20

–30

concentration of sucrose(%)

changein mass

(%)1 2 3 4 5

c) Use your graph to estimate at what point the concentration of sucrose in the potatois equal to the sucrose concentration in the beaker. (1 mark)

d) Explain why some of the potato cubes gained mass. (2 marks)

- 24 -

4. For each of the following, indicate whether the optimum pH is acidic, basic or neutral andexplain why that pH is needed for normal functions.

(6 marks: 1 mark each for optimum pH; 1 mark each for explanation)

stomach:

Optimum pH:

Explanation:

small intestine:

Optimum pH:

Explanation:

seminal fluid:

Optimum pH:

Explanation:

OVER- 25 -

5. Complete the following table describing components of the blood. (6 marks: 1 mark each)

RedBlood Cells Platelets

StructuralDescription

Function

Site of Production

- 26 -

6. When people are involved in an exercise program, changes in the circulatory system occur.

a) Explain why the number of capillaries in the skeletal muscle tissue increases. (2 marks)

b) Explain why the maximum heart rate is lower for the same amount of exercise. (2 marks)

OVER- 27 -


X

Y

Z

7. a) Identify each of the following structures. (2 marks: 1 mark each)

Structure X:

Structure Y:

b) Identify the substance stored and released by structure Z and describe its function.(2 marks: 1 mark for substance; 1 mark for function)

Substance:

Function:

c) Draw an arrow on the diagram above to indicate the direction of the nerve impulse.(1 mark)

- 28 -


OVER- 29 -


Y

X

8. a) Identify structure X. (1 mark)

b) What is the function of structure Y? (1 mark)

- 30 -

9. a) Write the names of the structures indicated by each of the arrows in the boxes provided.(3 marks)

OVER- 31 -

b) Give a function of each of the following in the excretory system.(4 marks: 1 mark each)

carrier proteins:

peritubular capillary network:

sodium bicarbonate:

aldosterone:

- 32 -

10. Identify three components of seminal fluid and give one function of each component.(6 marks: 1 mark each for name; 1 mark each for function)

Component Function

END OF EXAMINATION

MINISTRY USE ONLY



MINISTRY USE ONLY


MINISTRY USE ONLY

Biology 12

NOVEMBER 2002

Course Code = BI








Question 1:

1. .

(6)

Question 2:

2. .

(3)

Question 3:

3. .

(4)

Question 4:

4. .

(4)

Question 5:

5. .

(9)

Question 6:

6. .

(5)

Question 7:

7. .

(3)

Question 8:

8. .

(3)

Question 9:

9. .

(6)

Question 10:

10. .

(3)

Question 11:

11. .

(4)

BIOLOGY 12

NOVEMBER 2002

COURSE CODE = BI


ValueSuggested





OVER- 1 -



INSTRUCTIONS: For each question select the best answer and record your choice on the ResponseForm provided. Using an HB pencil, completely fill in the circle that has the lettercorresponding to your answer.

Use the following diagram to answer questions 1, 2 and 3.

W

V

Y

U

X

Z

1. What occurs at the site of the structure labelled V?

A. translationB. ATP formationC. rRNA synthesisD. DNA replication

2. Drugs are detoxified at which structure?

A. WB. XC. YD. Z

3. Which of the following is the correct sequence of organelles required in the production andexport of amylase?

A. V → W → XB. V → X → ZC. V → Z → UD. W → V → U

- 2 -


4. The organelle above is abundant in cells involved in

A. active transport.B. diffusion of oxygen.C. transport of hemoglobin.D. transport of lipid-soluble molecules.


+

–+

+

–+

+

–+

X

5. The bonding indicated by X occurs because

A. the molecules are polar.B. each molecule has a similar pH.C. the molecules have similar charges.D. the structures are unit molecules of a polymer.

OVER- 3 -

6. Which of the following has the greatest concentration of hydrogen ions?

A. saltB. acidC. baseD. water


+

H

HO

CH2OH

H

H

OH

O

OH

H

H

OH

H

HO

CH2OH

H

H

OH

O

OH

H

H

OH

H

HC

CH2OH

H

H

OH

O

OH

H

H H

HO

CH2OH

H

H

OH

O

OH

H

H

OH

O + H2O

7. The diagram illustrates a reaction that would take place during the

A. digestion of starch.B. formation of glycogen.C. hydrolysis of a protein.D. synthesis of a saturated fat.

________________________________________________

8. Which of the following molecules makes up plant cell walls and cannot be digested byhuman enzymes?

A. starchB. maltoseC. celluloseD. glycogen

- 4 -


1. complementary nitrogenous basesjoin by hydrogen bonding

2. the sugar of one nucleotide joins to thephosphate of the adjacent nucleotide

3. hydrogen bonds break to expose bothstrands of DNA

4. two identical molecules of DNA areformed

9. Which of the following is the correct sequence to describe DNA replication?

A. 1→ 2 → 3 → 4B. 2 → 3 → 4 → 1C. 3 → 1→ 2 → 4D. 4 → 3 → 2 → 1

________________________________________________

10. Which of the following is a characteristic of cancerous tissue?

A. controlled growthB. increased vascularizationC. increased contact inhibitionD. specialization of structure and function

11. Which of the following is not one of the seven known danger signals associated withthe presence of cancer?

A. a persistent headacheB. a sore that does not healC. unusual bleeding or dischargeD. an obvious change in a wart or mole

OVER- 5 -


• viruses• antibodies• tobacco smoke• ultraviolet radiation

12. How many of the factors above may act as initiators?

A. 1B. 2C. 3D. 4


X

W

Y

Z

13. The fluid nature of the cell membrane is dependent on which labelled molecule?

A. WB. XC. YD. Z

________________________________________________

14. Which type of molecules move sodium ions through the cell membrane?

A. proteinsB. cholesterolC. phospholipidsD. carbohydrates

- 6 -


1% glucose2% sucrose

5% glucose4% sucrose

15. The bag in the beaker above is only permeable to water. What will happento the concentration of glucose and sucrose in the solution in the beaker after 24 hours?

Glucose Sucrose

A. decrease increase

B. increase increase

C. increase decrease

D. decrease decrease

16. Which of the following processes occurs during the 24 hours?

A. osmosisB. pinocytosisC. active transportD. facilitated transport

17. Initially, the solution in the bag will be

A. hypertonic to the solution in the beaker, and becomes isotonic after 24 hours.B. hypertonic to the solution in the beaker, and becomes hypotonic after 24 hours.C. hypotonic to the solution in the beaker, and becomes isotonic after 24 hours.D. hypotonic to the solution in the beaker, and becomes hypertonic after 24 hours.

OVER- 7 -

18. What conditions would decrease the ability of lipase to form an enzyme-substrate complex?

A. a pH of 8.5B. the addition of lipidsC. the addition of lead ionsD. an increase in the amount of bile available

19. An experiment was set up to measure the effect of temperature on catalase, an enzyme foundin the liver that breaks down hydrogen peroxide into water and oxygen gas. Four labelledtest tubes, each containing similar amounts of catalase and 2 mL of hydrogen peroxide, wereincubated at different temperatures.

W X Y Z

Which of the following matches the test tube with its correct temperature?

W X Y Z

A. 70°C 37°C 20°C 5°C

B. 5°C 20°C 37°C 70°C

C. 70°C 5°C 20°C 37°C

D. 5°C 70°C 37°C 20°C

- 8 -


Reaction rate versussubstrate concentration

in an enzyme-catalyzed reaction

reactionrate

substrate concentration

reactionrate

20. In the graph above, the curve levels off due to the

A. addition of a strong acid.B. addition of a competitive inhibitor.C. conversion of all of the substrate into product.D. substrate temporarily occupying all the active sites.

________________________________________________

21. A disease of which structure could cause a high concentration of glucose in the urine?

A. pancreasB. gall bladderC. lymph nodesD. thyroid gland

OVER- 9 -


X

Y


A. arterial ductB. venous ductC. oval openingD. umbilical artery

23. Which of the following would result if structure Y remains functional after birth?

A. higher than normal levels of oxyhemoglobin in the aortaB. higher than normal levels of bicarbonate ions in the aortaC lower than normal levels of reduced hemoglobin in the aortaD. lower than normal levels of carbaminohemoglobin in the aorta

- 10 -

24. Which of the following correctly describes the structure and function of a red blood cell?

Structure Function

A. cell fragment initiates clotting

B. has a nucleus fights infection

C. biconcave produces antibodies

D. no nucleus transports hydrogen ions

25. What occurs at the venous end of a capillary bed?

A. Urea and ammonia exit into the tissues.B. Carbon dioxide and glucose enter the bloodstream.C. Blood pressure forces water to exit into the tissues.D. Osmotic pressure causes water to move into the blood.

26. When the left ventricle contracts, blood moves through

A. a semilunar valve into the aorta.B. a semilunar valve into the left atrium.C. an AV valve into the pulmonary artery.D. the arterial opening into the right ventricle.

27. Which part of the heart controls the rhythmic beat of the atria?

A. Purkinje fibresB. semilunar valveC. SA (sinoatrial) nodeD. AV (atrioventricular) node

28. During inspiration, which structure receives air after the bronchiole?

A. larynxB. tracheaC. alveolusD. bronchus

OVER- 11 -

29. Rings of cartilage strengthen which of the following structures?

A. tracheaB. alveolusC. diaphragmD. thoracic cavity


30. Which of the following pairs of reactions occurs most frequently in the blood surroundingthe structure shown?

A. Hb + O HbO HHb Hb + H2 2+→ →and

B. HbO Hb + O Hb + H HHb2 2+→ →and

C. H + Hb HHb H CO HCO + H+2 3 3

+→ → −and

D. CO + H O H CO H CO HCO + H2 2 2 3 2 3 3+→ → −and

________________________________________________

31. Within the respiratory system, debris is trapped by mucus in the

A. alveoli.B. trachea.C. bronchioles.D. pleural membranes.

- 12 -


1. medulla oblongata responds toincreased CO2 concentration

2. air rushes into the lungs

3. chest cavity volume increases

4. diaphragm relaxes

32. Which of the following is a correct sequence of events in breathing?

A. 4 → 1 → 3 → 2B. 3 → 2 → 1 → 4C. 3 → 4 → 1 → 2D. 4 → 2 → 3 → 1


X

33. Which of the following is a function of structure X?

A. to produce neurotransmittersB. to speed conduction of the nerve impulseC. to provide energy for nerve impulse conductionD. to receive stimulation for production of the nerve impulse

34. What type of cell is shown above?

A. a dendriteB. an interneuronC. a motor neuronD. a sensory neuron

OVER- 13 -


– – – – – – – – – + + + + + – – – – – – – –

– – – – – – – – – + + + + + – – – – – – – –

Na+

Na+

K+

K+

+ + + + + + + + + – – – – – + + + + + + +

+ + + + + + + + + – – – – – + + + + + + +

AreaX

AreaY

direction ofnerve impulse

35. What would occur in Area X when the event shown there later occurs in Area Y?

A. depolarizationB. K+ would enter the axonC. generation of a new impulseD. the membrane potential would approach –65 mV

________________________________________________

36. Which of the following inhibits the contraction of muscles which move food through thedigestive system?

A. cerebellumB. somatic nervous systemC. sympathetic nervous systemD. parasympathetic nervous system

- 14 -

Use the following list of hormones to answer question 37.

• thyroxin• estrogen• oxytocin• aldosterone• antidiuretic hormone• follicle-stimulating hormone

37. How many of the hormones above are released by the pituitary gland?

A. 2B. 3C. 4D. 5


X


A. renal pelvis.B. renal cortex.C. renal medulla.D. urinary bladder.

OVER- 15 -


X

Y

39. Which of the following occurs between X and Y?

A. tubular excretionB. pressure filtrationC. selective reabsorptionD. counter-current exchange

________________________________________________

40. Tubular excretion occurs when molecules move from the

A. loop of Henle to the renal medulla.B. Bowman’s capsule into the glomerulus.C. proximal tubule into the peritubular capillary network.D. peritubular capillary network into the distal convoluted tubule.

- 16 -


blood flow in

X

Y

blood flow out

41. Compared to structure Y, structure X contains

A. a higher concentration of urea.B. a higher concentration of glucose.C. a lower concentration of uric acid.D. a lower concentration of carbaminohemoglobin.

________________________________________________

42. In which structure is activity increased by raised concentrations of urea and salts in the blood?

A. pancreasB. adrenal cortexC. anterior pituitaryD. posterior pituitary

43. Aldosterone causes sodium to be reabsorbed by which part of the nephron?

A. loop of HenleB. collecting ductC. proximal tubuleD. distal convoluted tubule.

OVER- 17 -

44. All of the following have a similar function except for the

A. prostate gland.B. Cowper’s gland.C. seminal vesicles.D. seminiferous tubules.

45. Which of the following is the correct order of structures through which sperm pass as theyleave the body?

A. epididymis → urethra → vas deferens → seminiferous tubulesB. epididymis → urethra → seminiferous tubules → vas deferensC. seminiferous tubules → urethra → vas deferens → epididymisD. seminiferous tubules → epididymis → vas deferens → urethra


X

W

Y

Z

46. Which of the following provides energy to propel the sperm?

A. WB. XC. YD. Z

- 18 -

47. Higher levels of a hormone released from which of the following structures results in anincrease in muscle mass at puberty?

A. thyroidB. interstitial cellsC. adrenal medullaD. seminiferous tubules

48. Testosterone secretion is controlled through negative feedback due to increased amountsof which hormone?

A. oxytocinB. testosteroneC. progesteroneD. follicle-stimulating hormone (FSH)


X

49. What is the function of the structure labelled X?

A. It stores urine.B. It matures ova before ovulation.C. It receives the penis during copulation.D. It is the site of embryonic development.

OVER- 19 -

50. During birth, the concentration of a particular hormone in the mother’s blood was measuredat various times. Which of the following describes the feedback mechanism and the hormoneinvolved?

Type ofFeedback Hormone

A. positive oxytocin

B. negative oxytocin

C. positive progesterone

D. negative progesterone


- 20 -






1. Give two functions of each of the following.

water: (2 marks)

i)

ii)

lipids: (2 marks)

i)

ii)

lysosome: (2 marks)

i)

ii)

OVER- 21 -

2. Complete the table below by giving three differences between DNA and RNA.(3 marks: 1 mark for each contrasting pair)

DNA RNA

- 22 -

3. Describe the structure and function of each of the following molecules.(4 marks: 1 mark each for structure; 1 mark each for function)

mRNA:

structure:

function:

tRNA:

structure:

function:

OVER- 23 -

4. Explain how enzymes catalyze reactions in cells. (4 marks)

- 24 -

5. a) Describe how carbohydrates are digested and absorbed in the human digestive system.(6 marks)

b) Describe the role of the pancreas and the liver in maintaining blood sugar levels.(3 marks)

OVER- 25 -

6. In an effort to improve fitness level, an adult participates in a tennis program for five months.The following data were collected over this time period.

April August

resting pulse rate (beats/min) 75 65

pulse rate during exercise (beats/min) 140 110

time for pulse to return toresting rate after exercising (min) 13 2

resting blood pressure (mm Hg) 125/89 120/80

resting breathing rate (breaths/min) 17 15

breathing rate during exercise (breaths/min) 35 25

a) In August the person’s resting blood pressure is 120/80. Explain how the numbers120 and 80 relate to heart function. (2 marks)

b) Explain why the pulse rate during exercise went down between April and August. (1 mark)

c) Explain the change in breathing rate from resting to exercise. (2 marks)

- 26 -

7. Explain how the lymphatic and circulatory systems respond to a viral infection. (3 marks)

OVER- 27 -

8. Using the following table, distinguish between the chemical composition of the bloodin the arterial end and the venous end of a capillary bed in a muscle. (3 marks)

Arterial End Venous End

- 28 -


Y

XZ

9. Identify structures X, Y and Z and give one function of each.(6 marks: 1 mark each for name; 1 mark each for function)

structure X:

name:

function:

structure Y:

name:

function:

structure Z:

name:

function:

OVER- 29 -

10. Give one function of each of the following. (3 marks: 1 mark each)

renal pelvis:

proximal convoluted tubule:

ureter:

- 30 -

11. a) Complete the table for a typical 28-day ovarian cycle. (2 marks)

DaysPituitary Hormone Responsible

for Changes in the Ovary

1–12

15–28

b) Describe the hormonal changes that occur as a result of implantation. (2 marks)

END OF EXAMINATION

MINISTRY USE ONLY



MINISTRY USE ONLY


MINISTRY USE ONLY

Biology 12

AUGUST 2003

Course Code = BI

Student Instructions1. Place the stickers with your Personal

Education Number (PEN) in the allottedspaces above. Under no circumstance isyour name or identification, other thanyour Personal Education Number, toappear on this booklet.




*END OF EXAMINATION* .


Question 1:

1. .

(4)

Question 2:

2. .

(3)

Question 3:

3. .

(4)

Question 4:

4. .

(7)

Question 5:

5. .

(4)

Question 6:

6. .

(4)

Question 7:

7. .

(3)

Question 8:

8. .

(4)

Question 9:

9. .

(5)

Question 10:

10. .

(6)

Question 11:

11. .

(4)

Question 12:

12. .

(2)

BIOLOGY 12

AUGUST 2003COURSE CODE = BI



2. All multiple-choice answers must be entered on the Response Form using anHB pencil. Multiple-choice answers entered in this examination booklet willnot be marked.


4. Ensure that you use language and content appropriate to the purpose andaudience of this examination. Failure to comply may result in your paperbeing awarded a zero.



ValueSuggested


PART A: 50 multiple-choice questions 50 marks 45 minutes

PART B: 12 written-response questions 50 marks 75 minutes


OVER- 1 -



INSTRUCTIONS: For each question select the best answer and record your choice on the ResponseForm provided. Using an HB pencil, completely fill in the circle on the ResponseForm that has the letter corresponding to your answer.

1. What organelle contains enzymes that hydrolyze proteins?

A. ribosomesB. lysosomesC. rough endoplasmic reticulumD. smooth endoplasmic reticulum


X

W

Y

Z

2. Which labelled structure modifies polypeptides produced at the rough endoplasmic reticulum?

A. WB. XC. YD. Z

- 2 -

3. Which of the following increases in concentration when amino acids are dissolved in water?

A. H+

B. OH−

C. HCO3−

D. COOH

4. What is the empirical formula of a carbohydrate?

A. CH4

B. CHO

C. CH O2

D. C H O6 12 6

5. Which of the following would function as a structural component of plant cell walls?

A. OO

O

B. O

O

O

O

O

O OO

O

O

O

C.

O

O O OO

OO

O

O O OO

OO O

O

O

CH2

D.

O

O O OO

OO

O

O O OO

OO O

O

CH2

O

OO

O OO

O

O

O

O

O OO

O

O

O O

CH2

CH2

CH2

OVER- 3 -

6. What accounts for the secondary structure of a protein molecule?

A. hydrolysisB. denaturationC. ionic bondingD. hydrogen bonding

7. Which of the following is an example of complementary base pairing?

A. guanine—uracilB. adenine—cytosineC. cytosine—thymineD. cytosine—guanine

8. Which of the following is a characteristic of replication?

A. Sugar joins to phosphate groups, producing new DNA.B. Anticodons bond to codons by complementary base pairing, producing proteins.C. Adenine bonds with thymine and cytosine bonds with guanine, producing mRNA.D. Adenine bonds with uracil and cytosine bonds with guanine, producing new DNA.

9. What is meant by the term “unzipping” as it occurs during replication?

A. denaturing of the DNA moleculeB. formation of temporary bonds between mRNA and tRNAC. breaking the bonds between the bases of DNA nucleotidesD. breaking the bonds between the sugar and phosphate molecules

- 4 -


W X Y

Z

10. Which of the following correctly identifies the parts labelled W, X, Y and Z?

W X Y Z

A. phosphate ribose cytosine guanine

B. thymine uracil ribose phosphate

C. adenine thymine phosphate ribose

D. adenine thymine deoxyribose phosphate

________________________________________________


11. What are two characteristics of the cells shown in the diagram?

A. rapid growth and low metabolic rateB. contact inhibition and abnormal nucleiC. lack of contact inhibition and disorganized growthD. contact inhibition and the inability to cause vascularization

OVER- 5 -

12. When asbestos dust causes normal genes to become cancer-causing genes it is acting as

A. a promoter.B. an initiator.C. an inhibitor.D. an oncogene.

13. Which of the following does not affect the rate of an enzyme-catalyzed reaction?

A. pHB. temperatureC. osmotic pressureD. substrate concentration

14. Vitamins act as which of the following in biochemical reactions?

A. buffersB. enzymesC. substratesD. coenzymes

15. What structure prevents food from entering the trachea?

A. the tongueB. the pharynxC. the epiglottisD. the cardiac sphincter

16. Which is a function of the large intestine?

A. the secretion of bileB. the absorption of vitaminsC. the production of glycogenD. the release of sodium bicarbonate

- 6 -


blood amino acidconcentration in

hepatic portal vein(mg/100 ml)

50

timeX

17. What enzyme is responsible for the change at time X?

A. lipaseB. amylaseC. nucleaseD. peptidase

________________________________________________

18. Which of the following is a reactant in the chemical digestion of food?

A. waterB. enzymesC. hormonesD. heavy metals

19. Which enzyme functions optimally in a low pH?

A. lipaseB. pepsinC. trypsinD. amylase

20. What would result if insulin was injected into a healthy person?

A. Blood glucose levels would increase.B. The liver would convert glycogen into glucose.C. Glucose concentration in body cells would increase.D. The cell membrane would become less permeable to glucose.

OVER- 7 -

21. The removal of the gall bladder would affect the rate of digestion of which of the following?

A. lipidsB. proteinsC. nucleotidesD. carbohydrates

22. Which of the following results in an increase in the surface area of food?

A. lipase digesting starchB. peristalsis in the stomachC. synthesis of glycogen in the liverD. absorption of water in the large intestine

Use the following table to answer question 23.

Bloodvessel

Average blood pressure(mm Hg)

Total cross-sectional area( cm2 )

W 100 2.5

X 1 8

Y 20 2500

Z 60 40

23. Through which vessel would blood move most slowly?

A. WB. XC. YD. Z

________________________________________________

24. What two vessels carry blood to the anterior vena cava?

A. the jugular vein and the iliac veinB. the jugular vein and the subclavian veinC. the hepatic portal vein and the renal veinD. the coronary vein and the pulmonary vein

- 8 -

25. Which of the following maintains the osmotic pressure of the blood?

A. ureaB. proteinC. glycogenD. phospholipids


W

X Y

Z

26. Which of the labelled structures prevents blood from re-entering the right atrium from theright ventricle?

A. WB. XC. YD. Z

________________________________________________

27. Through how many heart valves must a blood cell pass as it moves from the brain tothe lungs?

A. 2B. 4C. 6D. 8

OVER- 9 -

28. What is the effect of acetylcholine on the body?

A. It decreases the heart rate.B. It increases the blood pressure.C. It decreases the blood flow to the skin.D. It decreases the blood flow to the digestive system.

29. Cilia in the trachea sweep debris toward which of the following structures?

A. the alveoliB. the bronchiC. the pharynxD. the bronchioles

30. What structure, composed of thin-walled epithelial cells that secrete lipoproteins, allows thediffusion of gases?

A. the alveolusB. the bronchioleC. the diaphragmD. the pleural membrane

31. Which of the following occurs during exhalation?

A. The diaphragm flattens.B. The rib muscles contract.C. Air pressure increases in the lungs.D. The thoracic cavity increases in volume.

- 10 -


X

Y

Z

32. Which of the following occurs if the neuron is stimulated at Y?

A. The nerve impulse will travel to X and then to the brain.B. The nerve impulse will travel to a sensory receptor located at Z.C. The nerve impulse will travel to Z and then stimulate an effector.D. The nerve impulse will travel to X and stimulate the release of neurotransmitters.

________________________________________________

33. Which of the following events causes the polarity to change from –65mV to +40mVacross the membrane of the axon?

A. the diffusion of sodium ions into the axonB. the diffusion of potassium ions into the axonC. the active transport of sodium ions out of the axonD. the active transport of potassium ions out of the axon

34. Which of the following would initiate an action potential?

A. the release of neurotransmitters from the postsynaptic membraneB. the exit of potassium ions from the axon during the refractory periodC. the depolarization of the dendrite when the threshold level is reachedD. the decreased permeability of the presynaptic membrane to calcium ions

35. What is the function of hydrolytic enzymes in the synaptic cleft?

A. to increase the threshold levelB. to break down neurotransmittersC. to stimulate contractile proteins in the synaptic endingD. to increase the permeability of the presynaptic membrane to calcium ions

OVER- 11 -

36. Which of the following causes nerve impulses to move more quickly along the neuron?

A. the presence of the myelin sheathB. an increased intensity of the action potentialC. the stimulation of the parasympathetic nervous systemD. the action of hydrolytic enzymes present in the synaptic gap


X

37. The structure labelled X is located in what part of the kidney?

A. the renal arteryB. the renal pelvisC. the renal cortexD. the renal medulla

________________________________________________

38. Where does active transport play an important role in urine formation?

A. in the glomerulusB. in the renal arteryC. in the Bowman’s capsuleD. in the distal convoluted tubule

- 12 -

39. Urine enters the bladder through which structure?

A. the ureterB. the kidneyC. the urethraD. the collecting duct


X

WY

Z

40. Which labelled structure receives the contents of the collecting ducts?

A. WB. XC. YD. Z

________________________________________________

41. Upon what is filtration of blood in the glomerulus dependent?

A. blood pressureB. decreased blood volumeC. parasympathetic stimulationD. increased waste concentration in the blood

42. What structure secretes aldosterone?

A. the adrenal glandB. the hypothalamusC. the pituitary glandD. the medulla oblongata

OVER- 13 -

Use the following diagram to answer questions 43, 44, 45 and 46.

S

V

T

U

W

X

Y

Z

43. Which of the following correctly describes the pathway sperm follow from their formation totheir exit from the body?

A. U → Y → W → TB. S → Z → W → XC. S → Z → X → YD. S → Z → V → T

44. Which of the following is a function of the secretions from the structure labelled S?

A. to buffer the pH of the semenB. to cause beard growth at pubertyC. to cause rhythmic contractions of the uterusD. to cause increased secretion of releasing hormones

45. Structure X refers to which of the following?

A. the testesB. the epididymisC. the vas deferensD. the seminal vesicles

46. Which labelled structure transfers semen to the female?

A. XB. YC. ZD. U

- 14 -

47. Which of the following structures secretes testosterone?

A. the prostateB. the epididymisC. the vas deferensD. the interstitial cells


Z

Y

WX

48. Where does fertilization of an egg usually occur?

A. WB. XC. YD. Z

________________________________________________

49. What occurs when hormones are released by the corpus luteum?

A. Menstruation begins.B. The uterine lining thickens.C. The secretion of releasing hormones increases.D. The production of human chorionic gonadotropin (HCG) decreases.

OVER- 15 -

50. What effect would decreasing levels of estrogen and progesterone have on the femalereproductive system?

A. Ovulation would occur.B. The corpus luteum would degenerate.C. The endometrium would break down.D. The uterine lining would become secretory.


- 16 -


OVER- 17 -







XY

1. Name structures X and Y and explain how each functions in protein synthesis.(4 marks: 1 mark each for structure; 1 mark each for function)

structure X:

name:

function:

structure Y:

name:

function:

- 18 -

2. Draw a diagram showing the bonding between water molecules and explain how the structureof the water molecules allows these bonds to form. (You may use a pencil for your diagram.)

(3 marks: 1 mark for diagram; 2 marks for explanation)

explanation:

OVER- 19 -

3. Describe how each of the following contributes to the production of a protein. (4 marks)

DNA:

codon:

tRNA:

ribosome:

- 20 -


membrane

15% salt distilledwater

side A side B

4. An experiment was carried out to study the movement of molecules through a membrane.Two solutions were placed into a container on either side of a membrane which is permeableto salt and water. The temperature was maintained at 40 C° .

a) Describe what happens to the volume of the solution on both side A and side B afterfive hours. Explain your answer. (2 marks)

b) Describe what happens to the solute concentration on side B. Explain your answer.(3 marks)

OVER- 21 -

c) If the temperature at the beginning of the experiment was at 5 C° , describe howthe results obtained at 5 C° would be different from the results obtained at 40 C° .Explain your answer. (2 marks)

- 22 -

Use the following symbols to answer question 5.

products

enzyme

substrate

5. Using all of the symbols above as often as necessary, produce a diagram to illustratehow enzymes function. Explain your diagram. (You may use a pencil for your diagram.)

(4 marks: 2 marks for diagram; 2 marks for explanation)

explanation:

OVER- 23 -

6. Explain how the small intestine is specialized for the absorption of nutrients. (4 marks)

7. Describe three roles of the lymphatic system. (3 marks)

i)

ii)

iii)

- 24 -

8. Complete the following table.(4 marks: 1 mark each for location; 1 mark each for function)

Structure Location in the heart Function

Sinoatrial (SA) node

Purkinje fibres

OVER- 25 -

9. a) Compare the pH and temperature of the blood in the lung capillaries with the bloodin the capillaries of other body tissues. (2 marks)

b) How does the pH and temperature of the blood in the body tissues affect the ability ofoxygen to bind to hemoglobin? (1 mark)

c) How would the conditions of the blood in the body tissues change during strenuousexercise? (2 marks)

- 26 -

10. a) Identify the division of the autonomic nervous system that is involved in the“fight or flight” response. (1 mark)

b) Identify the hormone involved in the “fight or flight” response, name its source gland, andgive three effects that the hormone has on the body.

(5 marks: 1 mark for hormone; 1 mark for source gland; 3 marks for effects)

hormone:

source gland:

effects:

i)

ii)

iii)

OVER- 27 -

11. Describe how the secretion of each of the following will affect the composition of blood.(4 marks: 2 marks each)

aldosterone:

antidiuretic hormone:

- 28 -

12. Explain what happens to the uterine lining during the first five days of the uterinecycle and explain why this occurs. (2 marks)

END OF EXAMINATION

MINISTRY USE ONLY



MINISTRY USE ONLY


MINISTRY USE ONLY

Biology 12

JUNE 2003

Course Code = BI








Question 1:

1. .

(3)

Question 2:

2. .

(3)

Question 3:

3. .

(2)

Question 4:

4. .

(4)

Question 5:

5. .

(3)

Question 6:

6. .

(6)

Question 7:

7. .

(6)

Question 8:

8. .

(2)

Question 9:

9. .

(4)

Question 10:

10. .

(4)

Question 11:

11. .

(4)

Question 12:

12. .

(4)

Question 13:

13. .

(2)

Question 14:

14. .

(3)

BIOLOGY 12

JUNE 2003COURSE CODE = BI





4. Ensure that you use language and content appropriate to the purpose and audienceof this examination. Failure to comply may result in your paper being awardeda zero.



ValueSuggested





OVER- 1 -




1. Which of the following cells could produce the greatest amount of lipase?

A. B.

C. D.

- 2 -

2. Phagocytosis involves the infolding of what structure?

A. the nucleolusB. the mitochondriaC. the cell membraneD. the smooth endoplasmic reticulum


H

OH

3. The polarity of the molecule above accounts for which of the following characteristics?

A. an acidic pHB. low density as a liquidC. its ability to act as a solventD. its ability to buffer reactions

OVER- 3 -


X

Z

Y Y

4. What does the molecule labelled Y represent?

A. ATPB. waterC. oxygenD. carbon dioxide

5. If the molecules at X represent amino acids, then what does the molecule at Z represent?

A. insulinB. glycerolC. glycogenD. messenger RNA


H

HOOH

H

H

OH

CH2OH

HO H

O

H

OH

H

H

OH

CH2OH

HO H

OH

6. What is the molecule illustrated above?

A. glycogenB. a nucleotideC. an amino acidD. a disaccharide

- 4 -


+

7. Where in the cell does this process take place?

A. in the nucleusB. in the ribosomeC. in the Golgi bodyD. in the rough endoplasmic reticulum

________________________________________________

8. Which of the following are characteristics of DNA but not of RNA?

A. single stranded contains adenine translates

B. double stranded contains guanine replicates

C. single stranded contains thymine replicates

D. double stranded contains uracil translates

OVER- 5 -


MoleculeX

Y Z

9. What process produces molecule X?

A. translationB. replicationC. denaturationD. transcription

10. What type of bond joins the structure in box Y with the structure in box Z?

A. ionicB. peptideC. covalentD. hydrogen

11. What two components are part of the structure shown in box Y?

A. ribose and guanineB. ribose and cytosineC. deoxyribose and uracilD. deoxyribose and adenine

- 6 -

12. What is produced during translation?

A. messenger RNAB. steroid hormonesC. a polypeptide chainD. new DNA molecules

13. What molecules act as carriers of glucose in the cell membrane?

A. proteinsB. nucleic acidsC. phospholipidsD. carbohydrates

14. Which of the following describes active transport?

A. Water moves across the cell membrane.B. Small molecules are pushed into the tissue fluid by blood pressure.C. Molecules are moved against the concentration gradient using energy.D. Molecules are moved with the concentration gradient without using energy.


• temperature

• shape of molecule

• concentration gradient

15. How many of the conditions above would affect the rate of diffusion acrossa semipermeable membrane?

A. 0B. 1C. 2D. 3

OVER- 7 -


time

white blood cell

bacterium

16. What is the next step in the process shown above?

A. Water is drawn into the cell.B. Enclosed substances leave the cell.C. A lysosome fuses with the vacuole.D. A vesicle fuses with the cell membrane.

________________________________________________

17. The appendix is attached to which of the following structures?

A. the colonB. the stomachC. the gall bladderD. the small intestine

18. Which of the following compares the blood glucose concentration in the hepatic portal vein tothat of the hepatic vein after the digestion of carbohydrate-rich food?

A. Blood glucose concentration is higher in the hepatic vein due to the actionsof insulin.

B. Blood glucose concentration is higher in the hepatic vein because the liver storesexcess glucose.

C. Blood glucose concentration is similar in each vein because glucose remains in thebloodstream.

D. Blood glucose concentration is lower in the hepatic vein because glucose is convertedto glycogen.

- 8 -


Vessel YVessel X Vessel Z

19. The diagrams above illustrate cross-sectional views of three different types of blood vessels.Which of the following correctly describes the characteristics of each blood vessel?

Vessel X Vessel Y Vessel Z

A. carries bloodto the heart

containsone-way valves

contraction ofskeletal muscleaids blood flow

B. blood velocityis highest in this

type of vessel

carries bloodtoward the heart

exchanges gases,nutrients and wastes

with tissue fluids

C. smooth muscleallows for contraction

carries bloodfrom the heart

carries bloodtoward the heart

D. contraction ofskeletal muscle aids blood flow

smooth muscleallows for contraction

blood velocityis lowest in thistype of vessel

OVER- 9 -

20. Which of the following graphs illustrates the changes in the blood pressure between thepulmonary trunk and the left atrium?

A.

bloodpressure(mm Hg)

pulmonarycapillaries

pulmonarytrunk

leftatrium

B.



pulmonarytrunk

leftatrium

C.



pulmonarytrunk

leftatrium

D.



pulmonarytrunk

leftatrium

________________________________________________

21. Which of the following statements is true?

A. Arteries have thinner walls than veins.B. Veins have greater elasticity than arteries.C. Arteries have one-way valves and veins do not.D. Veins have a larger internal diameter than arteries.

22. What blood vessel carries oxygen and nutrients to the heart muscle?

A. the aortaB. the carotid arteryC. the coronary arteryD. the pulmonary artery

- 10 -


W

Z

Y

X

23. Which labelled blood vessel would contain the highest concentrations of oxygen and nutrients?

A. WB. XC. YD. Z

OVER- 11 -

24. What structures are responsible for collecting excess tissue fluids in the body?

A. the venulesB. the lymph nodesC. the blood arteriolesD. the lymph capillaries

25. Which of the following is found in greater amounts in the blood of a person witha viral infection?

A. ureaB. plateletsC. antibodiesD. red blood cells

26. Which of the following describes the net movement of water at the arterial end of acapillary bed?

A. net movement of water into the tissues because blood pressure is less than the osmoticpressure of the blood

B. net movement of water into the tissues because blood pressure is greater than the osmoticpressure of the blood

C. net movement of water into the capillaries because blood pressure is less than the osmoticpressure of the blood

D. net movement of water into the capillaries because blood pressure is greater than the osmoticpressure of the blood

27. The secretion of which of the following would lead to a decrease in blood pressure?

A. adrenalineB. aldosteroneC. acetylcholineD. antidiuretic hormone

- 12 -


X

Y

Z

W

28. Which arrow indicates the location of the vocal cords?

A. WB. XC. YD. Z

________________________________________________

29. What structure prevents food from entering the trachea?

A. the pharynxB. the epiglottisC. the diaphragmD. the bronchioles

30. Which of the following events occurs during exhalation?

A. The diaphragm flattens and the rib muscles relax.B. The diaphragm flattens and the rib muscles contract.C. The diaphragm becomes dome shaped and the rib cage moves up and out.D. The diaphragm becomes dome shaped and the rib cage moves down and in.

OVER- 13 -

31. High blood concentrations of which of the following substances increases the rate anddepth of breathing?

A. acetylcholineB. hydrogen ionsC. oxyhemoglobinD. carbonic anhydrase

32. What structure in a neuron contains the nucleus?

A. the axonB. the vesicleC. the dendriteD. the cell body

33. What event occurs during repolarization?

A. the sodium gates openB. the potassium gates openC. the net movement of sodium ions into the axonD. the net movement of potassium ions into the axon

34. To which structure does a nerve impulse travel after leaving the axon of an interneuron?

A. a receptorB. an effectorC. an axon of a sensory neuronD. a dendrite of a motor neuron

35. Which of the following is a function of the hormone produced by the adrenal medulla?

A. to increase the heart rateB. to decrease blood pressureC. to stimulate the actions of the digestive systemD. to stimulate the parasympathetic nervous system

- 14 -

36. If damage to the brain leads to difficulties in voluntary muscle response and speech, what areaof the brain is most likely affected?

A. the cerebrumB. the hypothalamusC. the pituitary glandD. the medulla oblongata


V

X

ZY

W

37. Which of the following are functions of X?

A. to regulate heart rate and breathing rateB. to control temperature and water balanceC. to control muscle co-ordination and balanceD. to integrate sensory information and act as a relay station

38. Which structures act as the neuro-endocrine control centre?

A. V and XB. V and ZC. W and XD. W and Y

OVER- 15 -

39. Which of the following correctly compares the relative concentrations of the given substancesin urine and blood in the renal vein?

Urine Blood in the renal vein

UreaHydrogen

ions Glucose UreaHydrogen

ions Glucose

A. high low high high low high

B. high high low low low high

C. low high low low low high

D. low low high high high low

40. How does the composition of blood in the renal vein change if ADH is secreted?

A. It contains more water.B. It contains more glucose.C. It contains more aldosterone.D. It contains more bicarbonate ions.

41. Which part of the nephron re-absorbs the majority of nutrients?

A. the glomerulusB. the loop of HenleC. the distal convoluted tubuleD. the proximal convoluted tubule

- 16 -


X

Z

W

Y

42. The cells of which labelled structure respond to aldosterone?

A. WB. XC. YD. Z

________________________________________________

43. What substance is increasingly re-absorbed as blood pH decreases?

A. ureaB. ammonia (NH3 )C. bicarbonate ions (HCO3

− )D. antidiuretic hormone (ADH)

44. The secretion of which of the following affects blood volume?

A. ADHB. thyroxinC. ammoniaD. bicarbonate ions

OVER- 17 -

45. Which of the following is not a function of seminal fluid?

A. to cause uterine contractionsB. to neutralize acidic pH of the vaginaC. to provide fructose for ATP productionD. to stimulate the ovaries to release an egg


X

Y

ZW

46. Which structure contains high numbers of mitochondria?

A. WB. XC. YD. Z

________________________________________________

47. Which of the following secrete female reproductive hormones?

A. the vagina and the cervixB. the uterus and the clitorisC. the follicle and the corpus luteumD. the fallopian tubes and the urethra

- 18 -

48. Which of the following is an effect of estrogen?

A. maturation of the corpus luteumB. decreased levels of LH secretionsC. increased levels of FSH secretionsD. increased thickness of the uterine lining

49. Which of the following describes the hormonal levels on day 13 of a 28-day uterine cycle?

Follicle-stimulatinghormone

Luteinizing hormone

A. low high

B. high high

C. low low

D. high low

50. What structure secretes luteinizing hormone?

A. the ovaryB. the placentaC. the corpus luteumD. the anterior pituitary


OVER- 19 -






1. Describe how the function of the cell membrane, vacuoles and lysosomes are related.(3 marks)

2. Describe three ways that water is important to living organisms. (3 marks)

i)

ii)

iii)

- 20 -


SP

P

PP

P

P

P

P

P P

P

P

P

PP

P

P

P

P

P

P

P

P

P

P

P

P

PS

S

SS

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S S

S

S

S

S

S

S

S

S

S

SP

SubstanceX

SubstanceY

3. A radioactive molecule is added to a cell culture where the process shown in the diagram istaking place. Upon analysis, it is found that substance Y is radioactive but substance X is not.Give a possible identity for the radioactive molecule which was added and explain why it isonly in substance Y. (2 marks: 1 mark for molecule; 1 mark for explanation)

molecule:

explanation:

OVER- 21 -

4. Each of the following diagrams illustrates an event in the growth and development of cancerin the body.

Event X Event Y

X ray

Event Z

a) Place the events in the correct order from the start of carcinogenesis. (1 mark)

b) Explain what is occurring in each of the events. (3 marks: 1 mark each)

event X:

event Y:

event Z:

- 22 -

5. Compare the process of facilitated transport with that of active transport. (3 marks)

OVER- 23 -

6. Explain how each of the following affects the rate of an enzyme-catalyzed reaction thatoccurs in the mouth. (6 marks: 2 marks each)

adding more enzyme:

changing the pH from 7.2 to 12:

lowering the temperature from 37 C° to 10 C° :

- 24 -


6 a.m. 7 a.m. 8 a.m. 9 a.m. 10 a.m. 11 a.m. 12 p.m. 1 p.m.

85

130

time of day

blood glucoseconcentration(mg/100 mL)

Blood Glucose Concentration vs. Time of Day

7. A person eats a well-balanced meal at 7 a.m. and again at 12 p.m. Explain the changes thatoccur in blood glucose concentration at each of the times indicated below.

(6 marks: 2 marks each)

between 7 a.m. and 8 a.m.

between 8 a.m. and 9 a.m.

between 11 a.m. and 12 p.m.

OVER- 25 -

8. a) Name the substance which emulsifies fat in the digestive system. (1 mark)

b) Explain how emulsification assists in the chemical digestion of fat. (1 mark)

9. a) What is the name of the pacemaker of the heart and where in the heart is it located?(2 marks)

name:

location:

b) Explain how the Purkinje fibres function to control heartbeat. (2 marks)

- 26 -

10. a) State three functions of hemoglobin. (3 marks)

i)

ii)

iii)

b) How does the hemoglobin found in the pulmonary artery differ from the hemoglobinfound in the pulmonary vein? (1 mark)

OVER- 27 -

11. Compare the structural similarities and differences of motor and sensory neurons.(4 marks: 2 marks for similarities; 2 marks for differences)

similarities:

differences:

- 28 -


X

W

Y

Z

12. Identify each of the labelled regions or structures. (4 marks)

region W:

region X:

structure Y:

structure Z:

- 29 -

13. Identify the source of follicle-stimulating hormone (FSH) in males and describe its effecton the testes. (2 marks)

source:

effect:

14. Give one function of each of the following hormones. (3 marks: 1 mark each)

testosterone:

progesterone:

oxytocin:

END OF EXAMINATION

MINISTRY USE ONLY



MINISTRY USE ONLY


MINISTRY USE ONLY

Biology 12

NOVEMBER 2003

Course Code = BI








Question 1:

1. .

(2)

Question 2:

2. .

(2)

Question 3:

3. .

(5)

Question 4:

4. .

(4)

Question 5:

5. .

(4)

Question 6:

6. .

(4)

Question 7:

7. .

(2)

BIOLOGY 12

NOVEMBER 2003COURSE CODE = BI


ValueSuggested





OVER- 1 -





X

Y

1. Which of the following best describes the function of the structure labelled X?

A. It produces ATP.B. It produces lipids.C. It produces ribosomal RNA.D. It stores hydrolytic enzymes.

2. Which of the following could be produced at the structure labelled Y?

A. rRNAB. tRNAC. testosteroneD. hemoglobin

________________________________________________

3. What is the function of the nucleolus?

A. It produces mRNA.B. It produces ribosomal subunits.C. It provides a site for transcription.D. It provides a site for ATP production.

- 2 -


H N C C

H H

ROH

O

4. This unit molecule is a component of which of the following polymers?

A. proteinB. fatty acidC. nucleic acidD. polysaccharide


OO

O

5. What is the molecule above?

A. glucoseB. maltoseC. celluloseD. glycogen


P

W

X Y

Z

P P

6. What part of the molecule above allows it to serve as the “energy currency” of cells?

A. WB. XC. YD. Z

OVER- 3 -


O

O OO

O

OO

O

O

O

O

HH

H

H H

H

HH

N

N N

NN

NN

NN

NN

NN

C

CC

CC

CC

CC

C CC

C

CCCC

C C CC

CCC

7. What determines the level of protein structure in the molecule above?

A. dehydration synthesis of amino acidsB. hydrogen bonding between amino acidsC. two or more polypeptides forming the moleculeD. covalent bonding between the R-groups of amino acids


8. Which of the following molecules is a major structural component of the organelle above?

A. starchB. glucoseC. neutral fatD. phospholipid

________________________________________________

9. What property of water allows it to form hydrogen bonds?

A. It has a neutral pH.B. Its molecules are polar.C. It is an excellent solvent.D. Its molecules can dissociate.

- 4 -

10. What is the function of HCO3− (bicarbonate ion) when it helps to maintain the blood pH

at about 7.4?

A. to act as a baseB. to act as an acidC. to buffer the bloodD. to catalyze reactions

11. During which process would adenine bond with thymine but not uracil?

A. translationB. replicationC. transcriptionD. dehydration synthesis

12. Which of the following is found in RNA but not in DNA?

A. riboseB. adenineC. maltoseD. phosphate

13. What is the percentage of guanine in a DNA sample containing 20% thymine?

A. 10%B. 20%C. 30%D. 40%


+

14. In which organelle does the above process occur?

A. nucleusB. nucleolusC. rough endoplasmic reticulumD. smooth endoplasmic reticulum

OVER- 5 -

15. Consider the following portion of an mRNA strand:

U A C G G G A U A

What are the anticodons that will be paired to this strand?

A. A T G C C C T A TB. A T A G G G T A CC. A U G C C C U A UD. U A C G G G A U A

16. During transcription, hydrogen bonds form between which of the following?

A. amino acid pairsB. mRNA and DNAC. mRNA and ribosomesD. sugar and phosphate molecules

17. Which of the following describes the fluid-mosaic model of a cell membrane?

A. phospholipids floating in a layer of glycoproteinsB. cholesterol embedded between a double layer of proteinC. a layer of protein molecules between two layers of celluloseD. protein molecules embedded in a double layer of phospholipids

18. Which of the following is an example of osmosis?

A. the absorption of water by the large intestineB. the absorption of amino acids by the small intestineC. the movement of carbon dioxide into the blood from the tissuesD. the movement of fluids from the glomerulus to Bowman’s capsule

19. Which of the following processes results in the production of ADP and phosphate?

A. the absorption of water by the large intestineB. the absorption of oxygen into the blood by the alveoliC. the movement of carbon dioxide from the tissues to the bloodD. the re-absorption of glucose by the proximal convoluted tubule

- 6 -

20. What process allows chloride ions to move into a cell without the use of energy?

A. osmosisB. endocytosisC. active transportD. facilitated transport


X


A. a vesicleB. a glycoproteinC. a phospholipidD. a channel protein

________________________________________________

22. What occurs when a cell is placed in a solution that has a higher concentration of solutethan its cytoplasm?

A. The volume of the cell increases.B. More solute diffuses out of the cell.C. More water leaves the cell than enters the cell.D. The concentration of solute in the cell decreases.

23. How do enzymes increase the rate of a reaction?

A. They produce energy.B. They become denatured.C. They produce coenzymes.D. They decrease the energy of activation.

OVER- 7 -

24. Why does maltase hydrolyze maltose but not starch?

A. Maltose is a vitamin.B. Starch denatures the tertiary structure of maltase.C. The active site of maltase is complementary to maltose.D. Maltose provides activation energy and starch does not.

25. How are coenzymes involved in enzymatic reactions?

A. They provide atoms for the reaction.B. They increase enzyme concentration.C. They provide energy for the reaction.D. They increase substrate concentration.

26. What is the function of thyroxin?

A. to cause ovulationB. to increase metabolic rateC. to decrease the rate of digestionD. to control the concentration of sodium ions in the blood


Reaction rate

Progress of reaction

X Y

reaction rate

27. The graph shows changes in the reaction rate of an enzyme-catalyzed reaction. What accountsfor the shape of the graph between X and Y?

A. There is not enough substrate.B. All the active sites are occupied.C. More coenzyme has been added.D. Heavy metal ions have been added.

- 8 -


E1 to E7 are enzymesS to Z are substrates

Y ZE6 E7

S T U V W XE1 E2 E3 E4 E5

28. In an experiment, substrate S was added to a beaker containing equal amounts of enzymesE1 to E7. The metabolic pathway in the diagram shows the reactions that occurred. After15 minutes a competitive inhibitor for E3 is added to the beaker and the reactions continue tocompletion. What would occur?

A. The rate of production of T would increase.B. The rate of production of Z would increase.C. The rate of production of X would increase.D. The rate of production of E4 would decrease.

________________________________________________

29. What two structures produce chemicals that digest proteins?

A. the liver and the pancreasB. the salivary and intestinal glandsC. the gastric glands and the pancreasD. the gastric glands and the gall bladder


• emulsification by bile• chewing in the mouth• churning in the stomach• nucleic acid digestion by nuclease• production of vitamins by bacteria

30. How many of the above are examples of physical digestion?

A. 2B. 3C. 4D. 5

OVER- 9 -

31. Which of the following is not produced in the liver?

A. bileB. ureaC. lipaseD. glycogen

32. When the liver is unable to break down red blood cells, which of the following would beproduced in decreased amounts?

A. maltoseB. peptidesC. fat dropletsD. nucleotides


W

X

YZ

33. Which of the labelled structures is the anterior vena cava?

A. WB. XC. YD. Z

- 10 -

34. What blood vessel supplies blood directly to the heart muscle?

A. the aortaB. the carotid arteryC. the coronary arteryD. the pulmonary artery

35. Where does lymphatic fluid enter the bloodstream?

A. the aortaB. the jugular veinC. the subclavian veinD. the pulmonary vein

36. Which vessel contains blood with the lowest concentration of dissolved carbon dioxide?

A. the aortaB. the carotid arteryC. the pulmonary veinD. the inferior vena cava

Use the following diagram and list of substances to answer question 37.

capillary

ureaoxygenglucoseamino acidscarbon dioxide

substances

X Y

bloodflow

37. How many of the substances would be found in relatively higher concentrations at point Ywhen compared to point X?

A. 1B. 2C. 3D. 4

OVER- 11 -

38. What structure does blood flow through immediately after leaving the right ventricle?

A. the aortaB. the AV valveC. the pulmonary veinD. the pulmonary trunk


0

40

80

120

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

Time (sec.)

Pressure(mm Hg)

X

39. What accounts for the blood pressure recorded at X?

A. The AV valves are opening.B. The ventricles are in diastole.C. The ventricles are contracting.D. Blood is entering the ventricles.

- 12 -

40. Which of the following graphs illustrates how blood pressure changes during sympatheticnervous system stimulation?

A.

Time

140

130

120

110

100

90

80

BloodPressure

B.

Time

140

130

120

110

100

90

80

BloodPressure

C.

Time

140

130

120

110

100

90

80

BloodPressure

D.

Time

140

130

120

110

100

90

80

BloodPressure


1. atria contract

2. Purkinje fibres conduct

3. SA node stimulates

4. AV node stimulates

5. ventricles contract

41. Which of the following describes a correct sequence?

A. 1 → 4 → 2 → 5B. 2 → 5 → 4 → 1C. 3 → 5 → 4 → 1D. 4 → 1 → 2 → 5

OVER- 13 -


X


A. the tracheaB. a bronchusC. the pharynxD. a bronchiole

________________________________________________

43. Which of the following directs mucus towards the pharynx?

A. cilia in the tracheaB. cartilage in the bronchiC. elastic fibres in the larynxD. lipoprotein layer in the alveoli

- 14 -


• Air rushes into the lungs.• The rib cage moves up and out.• The thoracic cavity increases in volume.• The diaphragm becomes dome shaped.• Pressure in the thoracic cavity decreases.

44. How many of the events listed occur during inhalation?

A. 2B. 3C. 4D. 5

________________________________________________

45. Which reaction occurs at the pulmonary capillaries and alveoli?

A. H Hb HHb+ + →

B. HbO O Hb2 2→ +

C. CO Hb HbCO2 2+ →

D. H HCO CO H O3 2 2+ −+ → +

46. Which of the following structures is found only in the central nervous system?

A. the axon of an interneuronB. the axon of a motor neuronC. the dendrite of a sensory neuronD. the cell body of a sensory neuron

OVER- 15 -


Membrane potential(millivolts)

Time(milliseconds)

–65

0

+40

X Y


47. Which of the following occurs between time X and time Y?

A. repolarizationB. depolarizationC. resting potentialD. refractory period

________________________________________________

48. What does the term “threshold” refer to during synaptic transmission?

A. the number of impulses in a given unit of timeB. the amount of stimulus required to cause depolarizationC. the maximum number of sodium ions that can exit the axonD. the maximum time neurotransmitters spend in the synaptic cleft

49. What process ensures that a greater concentration of sodium ions is maintained outside theaxon relative to the inside of the axon?

A. diffusion through sodium channelsB. transport by carriers and the use of ATPC. exocytosis due to infolding of the membraneD. facilitated transport by sodium-potassium carriers

- 16 -

50. What structure insulates nerve fibres and speeds up the conduction of a nerve impulse?

A. the cell bodyB. the dendritesC. the myelin sheathD. the nodes of Ranvier


X

Y

51. What is the function of the structure labelled X?

A. It produces ATP.B. It produces thyroxin.C. It carries sodium and potassium ions to the receptors.D. It carries neurotransmitters to the presynaptic membrane.

52. What does structure Y represent?

A. a sodium-potassium pump at an axonB. a receptor on a postsynaptic membraneC. a binding site for neurotransmitters on an axonD. an attachment site for calcium ions at a dendrite

OVER- 17 -

53. The autonomic nervous system includes

A. the brain and spinal cord.B. the somatic nervous system.C. the cerebellum and the medulla oblongata.D. the sympathetic and parasympathetic divisions.


W

X

Z

Y

54. Reflex actions, such as sneezing and vomiting, are controlled by which labelled region?

A. WB. XC. YD. Z

55. Which labelled region is responsible for fine motor co-ordination and balance?

A. WB. XC. YD. Z

- 18 -

56. Where is the loop of Henle located?

A. in the renal cortexB. in the renal medullaC. in the collecting ductD. in the Bowman’s capsule


W

X

Y

Z

57. At which labelled point would the concentration of glucose in the filtrate be highest?

A. WB. XC. YD. Z

58. Which labelled structure is affected by antidiuretic hormone (ADH)?

A. WB. XC. YD. Z

OVER- 19 -

59. Which of the following correctly compares the relative concentrations of the given substancesin the loop of Henle and the collecting duct?

Loop of Henle Collecting duct

Amino acids Histamine Amino acids Histamine

A. low low low high

B. high low low high

C. high high low low

D. low high high low

60. Where do large amounts of Na+and Cl− enter into the renal medulla?

A. at the loop of HenleB. at the collecting ductC. at the Bowman’s capsuleD. at the proximal convoluted tubule

61. What structure transfers sperm to the female?

A. penisB. testesC. prostateD. epididymis

62. What substance causes the secretion of both testosterone and progesterone?

A. luteinizing hormoneB. antidiuretic hormoneC. follicle-stimulating hormoneD. human chorionic gonadotropic hormone

- 20 -


X

63. What is the effect of secretions produced by structure X during days 15 to 28 ofthe uterine cycle?

A. The endometrium disintegrates and blood vessels rupture.B. The follicle matures producing large amounts of estrogen.C. A sudden rise in luteinizing hormone causes the follicle to release an egg.D. Increased amounts of progesterone are produced causing the endometrium to

become secretory.


X

64. What do secretions from the structure labelled X cause?

A. menstruation and follicle maturationB. ovulation and genital growth at pubertyC. thickening of the endometrium and breast developmentD. development of the corpus luteum and contraction of the uterus

OVER- 21 -

65. What are days 5 to 13 of the uterine cycle called?

A. the luteal phaseB. the follicular phaseC. the secretory phaseD. the proliferation phase

66. What is an effect of oxytocin?

A. release of an eggB. development of breastsC. loss of the endometriumD. contraction of the uterus

67. What is a function of estrogen on the female reproductive system?

A. rupturing of the follicleB. thickening of the uterine liningC. maturation of the corpus luteumD. degeneration of the endometrium


- 22 -







1. Name the product of this organelle that is required in the transport of materials acrossa cell membrane. Explain the product’s role in this process. (2 marks)

product:

explanation:

OVER- 23 -

Use the following chart of mRNA codons to answer question 2.

Three-letter codons of messenger RNA and the amino acids specified by the codons

AAUAAC

AAAAAG

Asparagine

Lysine

CAUCAC

CAACAG

Histidine

Glutamine

GAUGAC

GAAGAG

Asparatic acid

Glutamate

UAUUAC

UAAUAG

Tyrosine

Stop

AGUAGC

AGAAGG

Serine

Arginine

UGUUGC

UGAUGG

Cysteine

StopTryptophan

AUUAUCAUA

AUG

Isoleucine

Methionine

UUUUUC

UUAUUG

Phenylalanine

Leucine

ACUACCACAACG

Threonine

CCUCCCCCACCG

Proline

GCUGCCGCAGCG

Alanine

UCUUCCUCAUCG

Serine

CGUCGCCGACGG

Arginine

GGUGGCGGAGGG

Glycine

CUUCUCCUACUG

Leucine

GUUGUCGUAGUG

Valine

2. Consider the following DNA base sequence read from left to right:

C C A G G A A T A C C T

Determine the amino acid sequence that results from this DNA strand. (2 marks)

- 24 -

3. The following procedure demonstrates the effect of pH on the activity of the enzyme trypsin.

• 10 ml of a protein solution is added to each of five numberedtest tubes, each of which is buffered at a different pH.

• The pH of each of the test tubes is maintained.• An equal amount of a trypsin solution is added to each test tube.• The temperature is maintained at 37 C° .• Each test tube is analyzed after three hours.

The results are recorded in the table below:

Test Tube

1

2

3

4

5

pH

2.0

3.5

7.0

8.5

10.0

Amount of product(g)

0.3

0.8

1.7

3.5

2.1

a) Use the data from the table to produce a line graph which illustrates the“Amount of product vs. pH” (plot the pH on the x-axis). (2 marks)

OVER- 25 -

b) Name the chemical product found in each test tube. (1 mark)

c) Explain why less product is found in test tubes 1 and 2 than in the others. (1 mark)

d) Name an enzyme that could further digest the product found in each of the test tubes.(1 mark)

- 26 -

4. Compare the chemical composition of the blood in the right atrium of a fetus to the bloodin the right atrium of an adult. Give reasons for these differences.

(4 marks: 2 marks for the comparisons; 2 marks for the reasons)

5. Describe the process of exhalation. (4 marks)

- 27 -

6. Many substances are moved by active transport in the nephron. Using four examples,explain how active transport is involved in urine production. (4 marks)

7. Describe how the hypothalamus increases testosterone levels in the blood. (2 marks)

END OF EXAMINATION

MINISTRY USE ONLY



MINISTRY USE ONLY


MINISTRY USE ONLY

Biology 12

JANUARY 2003

Course Code = BI








Question 1:

1. .

(3)

Question 2:

2. .

(4)

Question 3:

3. .

(3)

Question 4:

4. .

(3)

Question 5:

5. .

(2)

Question 6:

6. .

(3)

Question 7:

7. .

(2)

Question 8:

8. .

(7)

Question 9:

9. .

(3)

Question 10:

10. .

(5)

Question 11:

11. .

(3)

Question 12:

12. .

(4)

Question 13:

13. .

(2)

Question 14:

14. .

(6)

10/20/00

BIOLOGY 12

JANUARY 2003COURSE CODE = BI


ValueSuggested





OVER- 1 -



INSTRUCTIONS: For each question select the best answer and record your choice on the ResponseForm provided. Using an HB pencil, completely fill in the circle that has the lettercorresponding to your answer.


YU

W

VX

Z

1. Which labelled organelle produces most of the ATP in the cell?

A. VB. WC. YD. Z

2. Which labelled organelle has a bilayer of phospholipids and pores through whichmRNA passes?

A. UB. VC. XD. Y

- 2 -

3. What could be produced by a cell with a large amount of smooth endoplasmic reticulum?

A. enzymesB. antibodiesC. hemoglobinD. testosterone


HO

H

HO

H

X

4. What type of bond is represented by X?


________________________________________________

5. Gastric juice contains a high concentration of which of the following?

A. H+

B. bileC. OH−

D. NaHCO3

6. Which of the following are lipids?

A. ATPB. DNAC. steroidsD. glycogen

OVER- 3 -


P

W

X Y

Z

P P

7. Which labelled part of the molecule is associated with energy storage?

A. WB. XC. YD. Z

________________________________________________

8. What is found in RNA but not in DNA?

A. uracilB. thymineC. deoxyriboseD. sugar-phosphate backbone

9. During what process are polypeptides assembled at the ribosomes?

A. hydrolysisB. translationC. replicationD. transcription

10. What does metastasis refer to?

A. mutation leading to a cancer-causing geneB. differentiated cells becoming undifferentiatedC. the formation of new blood vessels in a tumourD. the spread of cancerous cells throughout the body

- 4 -

11. What process occurs during the development of cancer which allows a growing tumour toeliminate carbon dioxide and metabolic wastes?

A. anaplasiaB. metastasisC. carcinogenesisD. vascularization

12. A substance that causes the expression of cancer-causing genes is acting as

A. an initiator.B. a promoter.C. an oncogene.D. a proto-oncogene.

13. What process does not require the use of ATP?

A. exocytosisB. pinocytosisC. active transportD. facilitated transport

14. Which of the following is an example of pinocytosis?

A. Transport vesicles are formed at the Golgi bodies.B. Small particles move because of osmotic pressure.C. Large molecules are engulfed and brought into the cell.D. A white blood cell forms a vacuole around a bacterium.

15. What will happen to an animal cell when it is placed into a concentrated salt solution?

A. It will excrete salt.B. Its volume will decrease.C. It will absorb more water.D. Its volume will remain the same.

OVER- 5 -


X

time

16. What could the structure labelled X contain?

A. bacteriaB. glycogenC. white blood cellsD. protein molecules

________________________________________________

17. Increased secretion by the thyroid gland results in which of the following?

A. increased use of oxygenB. decreased body temperatureC. increased synthesis of glycogenD. decreased carbon dioxide production

18. What could be added to an enzyme-catalyzed reaction to decrease its rate?

A. enzymesB. substrateC. lead ionsD. coenzymes

- 6 -


X

reaction rate

progress of reaction

19. What would cause the change in the rate of the enzyme-catalyzed reaction at X?

A. an increase in enzyme concentrationB. an increase in the temperature to 3 C7°C. a decrease in the substrate concentrationD. a decrease in the competitive inhibitor concentration


X Y

ZW

20. The absorption of water is the main function of which labelled structure?

A. WB. XC. YD. Z

OVER- 7 -

21. Which of the following is not a component of pancreatic juice?

A. lipaseB. amylaseC. hydrochloric acidD. sodium bicarbonate


W

Y

Z

X

22. Which labelled structure produces a substance which aids in the physical digestion of food?

A. WB. XC. YD. Z

________________________________________________

23. What part of the digestive tract has the greatest surface area?

A. the stomachB. the esophagusC. the large intestineD. the small intestine

24. Which of the following combinations will produce the most product in the presence of water?

A. amylase and fat at pH 7.4B. lipase and starch at pH 8.0C. trypsin and protein at pH 8.0D. nuclease and nucleic acid at pH 3.0

- 8 -


H N C

HH

R

C

O

OH

++ H2OH N C C N C C

H OH

H

R OH

OR

N C CH

R OH

OH

H

25. What enzyme catalyzes this reaction?

A. lipaseB. maltaseC. nucleaseD. peptidase

________________________________________________

26. Which enzyme is most effective at pH 2.5?

A. lipaseB. pepsinC. nucleaseD. salivary amylase

27. What is absorbed into the lacteals?

A. lipidsB. glucoseC. nucleotidesD. amino acids

28. Which of the following correctly compares the blood in the pulmonary arteries to the blood inthe aorta?

A. The blood in both vessels has low concentrations of oxyhemoglobin.B. The blood in both vessels has a high concentration of oxyhemoglobin.C. The blood in the pulmonary arteries has less oxyhemoglobin than the blood in the aorta.D. The blood in the pulmonary arteries has more oxyhemoglobin than the blood in the aorta.

OVER- 9 -

29. What is produced by white blood cells that inactivates bacteria or viruses?

A. antigensB. plateletsC. antibodiesD. hemoglobin

30. The chordae tendineae of the heart help to prevent the backflow of blood from the

A. atria into the ventricles.B. ventricles into the atria.C. ventricles into the aorta and pulmonary trunk.D. aorta and pulmonary trunk into the ventricles.

31. What valve opens when the heart chamber producing the highest blood pressure contracts?

A. the aortic semi-lunar valveB. the pulmonary semi-lunar valveC. the left atrioventricular valveD. the right atrioventricular valve

32. What vessel carries blood away from the right ventricle?

A. the aortaB. the vena cavaC. the pulmonary veinD. the pulmonary trunk

33. During exhalation, what structure does air pass through immediately after leaving thebronchioles?

A. the alveoliB. the bronchiC. the tracheaD. the pharynx

- 10 -


W

X

Y

Z

34. Which labelled structure maintains negative pressure in the thoracic cavity?

A. WB. XC. YD. Z

________________________________________________

35. What is a function of mucus in the respiratory tract?

A. to trap dust and debrisB. to activate carbonic anhydraseC. to decrease the pH in the lungsD. to increase the pressure in the lungs

OVER- 11 -

36. Which of the following events occurs during inhalation?

A. The rib muscles relax.B. The diaphragm flattens.C. The thoracic volume decreases.D. The rib cage moves down and in.

37. What occurs at the alveoli and pulmonary capillaries?

A. internal respirationB. external respirationC. the binding of hydrogen to hemoglobinD. the release of oxygen from hemoglobin

38. Which of the following substances formed during internal respiration counteracts a decrease inblood pH?

A. oxyhemoglobinB. carbonic anhydraseC. reduced hemoglobinD. carbaminohemoglobin

39. Which of the following conditions favours the release of oxygen from hemoglobinat the tissues?

A. increased levels of carbon dioxide and increased pHB. decreased pH and increased levels of carbaminohemoglobinC. increased levels of hydrogen ions and increased temperatureD. decreased levels of carbon dioxide and decreased temperature

40. What is a function of the parasympathetic nervous system?

A. It causes the pupils to dilate.B. It increases the breathing rate.C. It increases blood flow to the digestive system.D. It is responsible for the “fight or flight” reactions.

- 12 -

41. What structure in the brain regulates the heartbeat and contains reflex centres for swallowing?

A. the thalamusB. the cerebellumC. the corpus callosumD. the medulla oblongata


W

X

Y

Z

42. Which of the labelled arrows points to the renal cortex?

A. WB. XC. YD. Z

________________________________________________

43. Where does selective reabsorption occur?

A. in a collecting ductB. in the renal medullaC. in a Bowman’s capsuleD. in a proximal convoluted tubule

44. The function of which of the following is most dependent upon adequate blood pressure?

A. the glomerulusB. the loop of HenleC. the collecting ductD. the proximal convoluted tubule

OVER- 13 -


Z

Y

XW

45. Which labelled structure is the efferent arteriole?

A. WB. XC. YD. Z

________________________________________________

46. In what structure is the corpus luteum found?

A. the uterusB. the ovaryC. the clitorisD. the oviduct

47. What would be an effect of high estrogen concentrations in the female?

A. The placenta would begin to develop.B. The follicle would increase the release of its secretions.C. The corpus luteum would reduce the release of progesterone.D. The anterior pituitary would reduce the release of follicle-stimulating hormone.

- 14 -


Z

Y

WX

48. What is represented by the structure labelled W?

A. the ovaryB. the uterusC. the vaginaD. the oviduct

49. Which labelled structure secretes hormones that cause the changes that occur in the femalebody during puberty?

A. WB. XC. YD. Z

50. What will occur at X as a result of a reduction in the secretion of GnRH(gonadotropin-releasing hormone)?

A. The follicle will not mature.B. The secretion of estrogen will increase.C. The secretion of progesterone will increase.D. The corpus luteum will secrete human chorionic gonadotropin.


OVER- 15 -







1. a) Name an organ whose cells contain large amounts of the organelle shown in the diagram.(1 mark)

b) Describe two functions of the organelle. (2 marks)

i)

ii)

- 16 -

2. In an experiment investigating conditions in the digestive tract, the concentration of hydrogenions was measured in three areas, A, B and C. The following graph shows the results.

concentrationof hydrogen ions

area of digestive tract

A

C

B

Identify areas A and B and explain how the conditions there contribute to proper digestion.(4 marks: 1 mark each for name; 1 mark each for explanation)

area A:

name:

explanation:

area B:

name:

explanation:

OVER- 17 -


3. List three structural components of the unit molecule that form the polymer shown.(3 marks)

i)

ii)

iii)

- 18 -


MoleculeX

MoleculeY

4. Describe three ways in which molecule X differs from molecule Y. (3 marks)

i)

ii)

iii)

OVER- 19 -


Y

X

5. a) Identify molecule X. (1 mark)

b) Give one function of the molecules labelled Y. (1 mark)

- 20 -


reaction rate

progress of reaction

X Y

A

B

C

6. The graph shows the change in the rate of an enzyme-catalyzed reaction over time.

a) Explain why the rate became constant at time X. (1 mark)

b) Which labelled line correctly illustrates what would occur if more enzyme was addedat time Y. Explain your answer. (2 marks)

________________________________________________

7. Name the organ that produces an enzyme which chemically digests fats and identifythe enzyme it produces. (2 marks)

organ:

enzyme:

OVER- 21 -


blood pressure(mm Hg)

heart capillaries

X

Y

8. a) Name and explain what is occurring in the heart to cause the conditions shown onthe graph at point X and point Y. (4 marks)

point X:

explanation:

point Y:

explanation:

b) Explain why blood pressure decreases as blood flows from the arteries to the capillaries.(1 mark)

c) Why is it important that blood flows very slowly in the capillaries? (1 mark)

d) Explain why blood velocity increases slightly as it moves from the capillaries to the veins.(1 mark)

- 22 -


76543210

25

50

75

100

125

150

average of systolicand diastolic blood pressure

(mm Hg)

time (min.)

time X

average of systolicand diastolic blood pressure

(mm Hg)

9. a) Describe the mechanisms at work in the body which led to the changes that occurredbetween minute two and minute three. (2 marks)

i)

ii)

b) If acetylcholine was administered at time X, describe the effect on the body. (1 mark)

OVER- 23 -

10. a) Describe the events that occur between the time a nerve impulse reaches the end ofan axon and the release of the neurotransmitters. (3 marks)

b) What happens to neurotransmitters after they are released into the synaptic cleft?(2 marks)

- 24 -


U

V

WX

Z

Y

11. Write the letter indicating the part of the brain with the following functions.(3 marks: 1 mark each)

Function Letter

the neuroendocrine control centre

ensures that skeletal muscle movesin a smooth and coordinated manner

allows nerve impulses to passbetween cerebral hemispheres

OVER- 25 -

12. List the structures, in the correct order, through which a glucose molecule passes as ittravels through the tubule from the renal artery to the renal vein.

(4 marks: 3 marks for structures; 1 mark for correct order)

- 26 -


gland X

13. How does gland X function to regulate sodium ion concentration in the blood? (2 marks)

- 27 -


day

1 14 287 21

relative levelsof hormones

hormoneX

hormoneY

14. a) Identify each of the following. (2 marks: 1 mark each)

hormone X:

hormone Y:

b) Describe the effect of hormone X on the female reproductive system duringdays 15 to 28 of a 28-day cycle. (2 marks)

c) What would occur during days 1 to 13 of the ovarian cycle if follicle-stimulatinghormone (FSH) was not secreted? (2 marks)

END OF EXAMINATION

MINISTRY USE ONLY



MINISTRY USE ONLY


MINISTRY USE ONLY

Biology 12

JUNE 2004

Course Code = BI






END OF EXAMINATION.


85966176

Question 1

0 1 2 3 (5) NR.

Question 4

0 1 2 3 4 (5) NR.

Question 5

0 1 2 3 4 (5) NR5 6 .

Question 6

0 1 2 3 4 (5) NR.

Question 2

0 1 (5) NR.2

Question 3

0 1 (5) NR.2 3 4

BIOLOGY 12

JUNE 2004COURSE CODE = BI


ValueSuggested





OVER- 1 -




1. Lipids are synthesized by which of the following cell structures?

A. nucleolusB. ribosomesC. Golgi bodiesD. smooth endoplasmic reticulum

2. Which organelle is present in large numbers in the interstitial cells of the testes?

A. lysosomeB. nucleolusC. rough endoplasmic reticulumD. smooth endoplasmic reticulum

3. What is the function of a buffer?

A. to prevent large changes in pHB. to act as a competitive inhibitorC. to decrease the energy of activationD. to increase the uptake of glucose into cells

- 2 -

4. Which of the following is a unit molecule of glycogen?

A.

NH2

R1 O

OHH

C C

B.

H

HO

OHH

C C

H

H

C

H

C

H

C

H

H

C

H

H

C

C.

C

H

HO

C

H

OH

C O

CH2OH

C C

OHH

OH H

H

D.

O

O

O

P O CH2

H

O

H H

HH

N N

OH

OCH3

H

H

________________________________________________

5. Which process can produce maltose?

A. the addition of water during the hydrolysis of a disaccharideB. the bonding of two saturated fatty acids and the addition of glycerolC. the bonding of two amino acids and the removal of one water moleculeD. the bonding of two monosaccharides and the removal of one water molecule

OVER- 3 -


CH

H

O C

O

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

HH C O C

O

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

C

H H

C O P

O

O C

H

H

C

H

H

+N

CH3

CH3

H

H O–

C

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

HC

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

HH

CH3

6. What is the molecule illustrated above?

A. ATPB. glycogenC. neutral fatD. phospholipid

________________________________________________

7. Which of the following polymers has the empirical formula CH O2 ?

A. DNAB. celluloseC. cholesterolD. saturated fat

- 4 -


O

O OO

O

OO

O

O

O

O

HH

H

H H

H

HH

N

N N

NN

NN

NN

NN

NN

C

CC

CC

CC

CC

C CC

C

CCCC

C C CC

CCC

8. What is the unit molecule of the polymer above?

A. glucoseB. fatty acidsC. nucleotidesD. amino acids

________________________________________________

9. Which of the following is a possible use for recombinant DNA?

A. producing steroid hormonesB. producing insulin using bacteriaC. cloning tissue cells for transplantD. encouraging nerve cells to regenerate

10. Which of the following is a definition of transcription?

A. the production of rRNA from tRNAB. the production of mRNA from DNAC. the production of protein by ribosomesD. the production of new DNA before cell division

OVER- 5 -


X

mRNA

11. Where is structure X produced?

A. in the nucleusB. in the nucleolusC. in the ribosomesD. in the endoplasmic reticulum

________________________________________________

12. Which of the following carries amino acids to the ribosome?

A. DNAB. tRNAC. rRNAD. mRNA

13. What is the anticodon which corresponds to the DNA base sequence G A C ?

A. C T GB. C U GC. G A CD. G U C

- 6 -

Use the following chart to answer question 14.


AAUAAC

AAAAAG

Asparagine

Lysine

CAUCAC

CAACAG

Histidine

Glutamine

GAUGAC

GAAGAG

Aspartic acid

Glutamate

UAUUAC

UAAUAG

Tyrosine

Stop

AGUAGC

AGAAGG

Serine

Arginine

UGUUGC

UGAUGG

Cysteine

StopTryptophan

AUUAUCAUA

AUG

Isoleucine

Methionine

UUUUUC

UUAUUG

Phenylalanine

Leucine

ACUACCACAACG

Threonine

CCUCCCCCACCG

Proline

GCUGCCGCAGCG

Alanine

UCUUCCUCAUCG

Serine

CGUCGCCGACGG

Arginine

GGUGGCGGAGGG

Glycine

CUUCUCCUACUG

Leucine

GUUGUCGUAGUG

Valine

14. The DNA strand C G A T G C G A C A T T undergoes a mutation in which the sectioncoding for the amino acid threonine is lost. Which of the following would be the correctcodons after this mutation?

A. A C G C U G U A AB. G C U A C G C U GC. G C U C U G U A AD. G C U A C G U A A

________________________________________________

15. Which molecule accounts for a cell membrane’s flexible and fluid nature?

A. proteinB. glycogenC. glycolipidD. phospholipid

OVER- 7 -


Y

Z

X

W

16. Which molecule allows cells to be recognized as foreign?

A. WB. XC. YD. Z

________________________________________________

17. For which of the following processes is ATP not required?

A. osmosisB. exocytosisC. pinocytosisD. active transport

- 8 -


% Change incell mass

% Solute

200 5 10 15 25

....................%Solu te

–20

–10

0

10

20

30

40

18. The data displayed on the graph above were collected in an experiment studying the effect ofchanges in solute concentration on the mass of tissue cells. What solute concentration isisotonic to the cells?

A. 0%B. 15%C. 23%D. 35%

________________________________________________

19. Which of the following characteristics facilitates an increase in the rate at which metabolicwastes leave the cell?

A. a large nucleusB. a spherical shapeC. an irregularly shaped surfaceD. a small surface area to volume ratio

20. Which of the following is a model used to describe enzymatic action?

A. translationB. transcriptionC. lock and keyD. dehydration synthesis

OVER- 9 -

21. Which of the following substances will cause an enzyme to be denatured?

A. vitaminsB. a substrateC. an inhibitorD. heavy metal ions


X

22. What is structure X?

A. the aortaB. the tracheaC. the esophagusD. the cardiac sphincter

- 10 -


X

Y

23. What structure is found between organ X and organ Y?

A. the appendixB. the epiglottisC. the pyloric sphincterD. the cardiac sphincter

24. What substance aids in the digestion of proteins in structure X?

A. lipaseB. pepsinC. trypsinD. amylase

OVER- 11 -


U

V

W

X

Y

Z

25. Which structures produce secretions which digest starch?

A. U, YB. V, WC. W, ZD. X, Z

________________________________________________

26. Which of the following is an effect of gastric secretions on digestion?

A. Trypsin breaks maltose down to glucose.B. An emulsifier increases the surface area of fats.C. Sodium bicarbonate increases pH facilitating the action of lipase.D. Hydrochloric acid maintains a low pH facilitating the action of pepsin.

27. What is peristalsis?

A. physical breakdown of fats by bileB. breakdown of food products by enzymesC. storage and compacting of feces in the rectumD. muscle contractions that assist the movement of food

- 12 -

28. How would decreased secretions by the liver affect digestion?

A. by decreasing chemical breakdown of fatsB. by decreasing physical digestion of proteinsC. by increasing absorption of materials into the lymph systemD. by increasing absorption of materials into the intestinal capillaries

Use the following diagrams to answer questions 29 and 30.

Vessel Y

Vessel X

Vessel Z

Vessel W

29. Which blood vessel carries oxygen and nutrients from the aorta to the heart muscle?

A. WB. XC. YD. Z

30. Which blood vessel exchanges nutrients and wastes with the tissues?

A. WB. XC. YD. Z

OVER- 13 -

31. What circulatory pathway carries blood to the lungs?

A. renalB. hepaticC. systemicD. pulmonary

32. What structure takes up tissue fluids not absorbed by the blood capillaries?

A. lymph vesselB. subclavian arteryC. hepatic portal veinD. posterior vena cava

33. What heart structure prevents the AV valves from inverting (turning inside out)?

A. SA nodeB. AV nodeC. Purkinje fibresD. chordae tendineae

34. Contraction of which heart chamber forces blood into the aorta?

A. left atriumB. right atriumC. left ventricleD. right ventricle

Use the following list of events to answer question 35.

• secretion of ADH• dilation of blood vessels• secretion of acetylcholine• sympathetic nervous system stimulation

35. How many of the events could cause a blood pressure reading of 160/100?

A. 1B. 2C. 3D. 4

- 14 -

36. Breathing rate is controlled by which of the following?

A. the alveoliB. the cerebral cortexC. the anterior pituitaryD. the medulla oblongata

37. What condition initiates exhalation?

A. high oxygen levels in the bloodB. low air pressure in the thoracic cavityC. low carbon dioxide levels in the bloodD. increased stimulation of the stretch receptors of the alveoli


Location inthe body

Amount ofO2 in the blood

(partial pressuremmHg)

Amount ofCO2 in the blood(partial pressure

mmHg)

W 40 45

X 42 42

Y 104 40

Z 40 104

38. The data table indicates the amounts of O2 and CO2 (partial pressure) in the blood at fourdifferent locations in the body. At which location is the blood leaving the lungs?

A. WB. XC. YD. Z

________________________________________________

39. Where are interneurons found?

A. within the pacemakerB. attached to muscle cellsC. between a stretch receptor and a motor neuronD. between the hypothalamus and the anterior pituitary

OVER- 15 -

40. Which of the following refers to the “threshold” of nerve transmission?

A. the frequency of action potentials which occur down a neuronB. the action potential created when potassium ions leave the neuronC. the total polarity change across the membrane during an action potentialD. the minimum level of stimulus necessary for an action potential to occur


X Y Z

direction of action potential

41. The diagram illustrates a section of an axon as an action potential proceeds from X to Z. If theaction potential has proceeded to Y, what prevents it from reversing direction?

A. Depolarization occurs at Z.B. Potassium gates are still open at X.C. The sodium-potassium pump stops working at X.D. Negatively charged ions have moved out of the axon at X.

- 16 -


Membrane potential(millivolts)

Time(milliseconds)

0

40+

65–

W X Y Z


42. The graph illustrates changes in membrane potential during the transmission of an actionpotential. What point on the graph corresponds to the time when repolarization begins?

A. WB. XC. YD. Z

________________________________________________

43. Which of the following illustrates the “all-or-none” response of a neuron?

A. repolarization will or will not occurB. depolarization will or will not occurC. all sodium ions inside the neuron will or will not cross the membraneD. all potassium ions inside the neuron will or will not cross the membrane

OVER- 17 -


X

YZ

W

44. Where in the myelinated axon would an action potential occur?

A. WB. XC. YD. Z

________________________________________________

45. The absorption of what ion begins the process which moves synaptic vesicles towardthe presynaptic membrane?

A. calciumB. chlorineC. potassiumD. bicarbonate

46. What is the advantage of reflex arcs?

A. They stop the sensation of pain in the brain.B. They provide a quick response to a stimulus.C. They take place independently of any nerve function.D. They allow us to think about an appropriate response to a stimulus.

47. What type of cells carry information to the central nervous system?

A. receptorsB. interneuronsC. motor neuronsD. sensory neurons

- 18 -


TimeHeart rate

(beats/minute)Breathing rate

(breaths/minute)

X 120 25

Y 65 12

48. The data table indicates the change in heart rate and breathing rate of a person who was understress. Which of the following could be responsible for the changes shown between time X andtime Y?

A. Adrenalin is released by the adrenal medulla.B. Noradrenalin is released by the sympathetic nervous system.C. Noradrenalin is released by the parasympathetic nervous system.D. Acetylcholine is released by the parasympathetic nervous system.

________________________________________________

49. What part of the brain is responsible for memory and thinking?

A. the thalamusB. the cerebrumC. the cerebellumD. the medulla oblongata

50. What structure transports urine from the bladder to the outside of the body?

A. the ureterB. the urethraC. the collecting ductD. the distal convoluted tubule

51. Which region of the kidney contains the glomeruli?

A. the renal cortexB. the renal medullaC. the adrenal cortexD. the adrenal medulla

OVER- 19 -

52. In addition to water, which of the following substances are the main components of urine?

A. urea and saltsB. ammonia and bileC. amino acids and fatty acidsD. hydrochloric acid and uric acid


X

53. Which of the following molecules is not normally found at X?

A. ureaB. waterC. glucoseD. hemoglobin

- 20 -

54. In which of the following does pressure filtration occur?

A. the glomerulusB. the afferent arterioleC. the efferent arterioleD. the peritubular capillaries

55. Which of the following conditions would lead to an increase in the amount of fluidentering the Bowman’s capsule?

A. dehydrationB. a decrease in systolic blood pressureC. constriction of the efferent arteriolesD. a decrease in the secretion of aldosterone

56. What area of the nephron is the site of hydrogen ion (H+) excretion?

A. the loop of HenleB. the collecting ductC. the distal convoluted tubuleD. the proximal convoluted tubule

57. Which of the following would result from the inhibition of ADH secretion?

A. a decrease in urine volumeB. an increase in the excretion of glucoseC. an increase in the concentration of urineD. a decrease in the amount of water re-absorbed

58. What structure secretes a hormone to regulate the concentration of sodium and potassiumin the blood?

A. the adrenal glandB. the thyroid glandC. the hypothalamusD. the pituitary gland

OVER- 21 -

Use the following list of structures to answer question 59.

• testes• urethra• vas deferens• prostate gland• Cowper’s gland

59. How many of the structures listed above contribute to the production of semen?

A. 2B. 3C. 4D. 5


W

X Z

Y

60. Which structure is a target of follicle-stimulating hormone (FSH)?

A. WB. XC. YD. Z

- 22 -


W

X

Y

Z

61. Which part of the cell uses ATP most rapidly?

A. WB. XC. YD. Z

________________________________________________

62. Which of the following would occur if the concentration of testosterone in the bloodwas too low?

A. The hypothalamus would produce more GnRH.B. The testes would produce less luteinizing hormone.C. The anterior pituitary gland would produce more testosterone.D. The hypothalamus would produce less follicle-stimulating hormone.

63. Through what structure does the egg travel in order to reach the uterus?

A. the ovaryB. the cervixC. the vaginaD. the oviduct

OVER- 23 -

64. Where are the hormones produced which cause the endometrium to become secretory duringthe uterine cycle?

A. in the uterusB. in the hypothalamusC. in the corpus luteumD. in the posterior pituitary

65. What is the result of increased luteinizing hormone secretion on day 14 ofthe ovarian cycle?

A. ovulationB. implantationC. menstruationD. degeneration of the corpus luteum

66. The onset of uterine contractions results in which of the following?

A. the secretion of less GnRHB. the secretion of more oxytocinC. the secretion of less progesteroneD. the secretion of more human chorionic gonadotropin

67. Implantation results in the secretion of what hormone?

A. progesteroneB. luteinizing hormoneC. follicle-stimulating hormoneD. human chorionic gonadotropin


- 24 -






1. Describe three cellular processes which make use of vesicles. (3 marks)

OVER- 25 -

2. Describe two ways in which enzymes are used during DNA replication. (2 marks)

- 26 -

3. Two digestive enzymes produced by two different glands act on the same substrate. Bothenzymes function optimally at a pH of 7.1 to 8.4 and a temperature of 37 C° .

a) Describe the similarity of the enzymes’ structures and explain why this affectstheir ability to act on the same substrate. (2 marks)

b) What would happen to the rate of the reaction above if the pH was changed to 3.0?Explain your answer. (2 marks)

OVER- 27 -

4. Describe two digestive reactions which occur as a result of pancreatic secretions. (4 marks)

- 28 -

5. Describe the location of each of the following fetal structures and explain their functionin fetal circulation. (6 marks: 2 marks each)

oval opening:

venous duct:

umbilical arteries:

- 29 -

6. Describe the events that lead to inhalation after stimulation by the respiratory centre. (4 marks)

END OF EXAMINATION

MINISTRY USE ONLY



MINISTRY USE ONLY


MINISTRY USE ONLY

Biology 12

AUGUST 2004

Course Code = BI






END OF EXAMINATION.


Question 4

0 1 2 3 4 (5) NR.

Question 5

0 1 2 (5) NR.

Question 6

0 1 2 3 (5) NR.

85966176

Question 7

0 1 2 3 (5) NR.

Question 3

0 1 2 3 4 (5) NR5 .

Question 2

0 1 2 (5) NR.

Question 1

0 1 2 3 4 (5) NR.

BIOLOGY 12

AUGUST 2004COURSE CODE = BI


ValueSuggested





OVER- 1 -




1. Which organelles produce molecules for cell recognition?

A. the ribosomesB. the lysosomesC. the Golgi bodiesD. the mitochondria


Diagram 1

V

Diagram 2

X Y

ZW

2. The structure labelled V in diagram 1 produces a substance that is a part of which cellularstructure in diagram 2?

A. WB. XC. YD. Z

- 2 -

3. What molecules are produced during the hydrolysis of dipeptides?

A. nucleotidesB. amino acidsC. fatty acids and glycerolD. glucose molecules and water

4. During what type of reaction do glucose molecules bond together to form starch?

A. synthesisB. hydrolysisC. translationD. transcription


CH

H

OHCH

OHCH

OHCH

H

HO

HO

HO

+

+

+

C

C

C

O

O

C

H

H

C C C C H

H H H H

HH

C

H

H

C C C C H

H H H H

HHH H

C

H

H

O

C C C H

H H H

HHH

C

H

H

Ï Ô Ô Ì Ô Ô Ó Ï Ô Ô Ô Ô Ì Ô Ô Ô Ô Ó

X Y

C

C

C

O

O

C

H

H

C C C C H

H H H H

HH

C

H

H

C C C C H

H H H H

HHH H

C

H

H

O

C C C H

H H H

HHH

C

H

H

CH

H

OCH

OCH

OCH

H

H2O

H2O

H2O

+

+

+

5. What are the structures labelled X and Y?

X Y

A. starch glycogen

B. amino acid tripeptide

C. glycerol fatty acid

D. glycogen ATP

OVER- 3 -

6. How are carbohydrates, lipids, proteins and nucleic acids similar?

A. They act as catalysts.B. They are made up of carbon atoms.C. They have a tertiary shape held together by hydrogen bonds.D. They form part of the phospholipid bilayer in the cell membrane.


CH2OHO

H

OH

OHH

OHHO

H H

H

7. Which polymer is formed by the monomer shown in the diagram?

A. lipidB. proteinC. sucroseD. glycogen

________________________________________________

8. Which element is present in proteins but not in most carbohydrates?

A. carbonB. oxygenC. nitrogenD. hydrogen

- 4 -


XÏÔÌÔÓ

9. Which of the following molecules is a component of X?

A. glucoseB. fatty acidsC. nucleotidesD. amino acids


P P P

X

10. What occurs when the bond labelled X is broken?

A. Energy is released.B. Water is produced.C. The molecule is denatured.D. Carbon dioxide is produced.

OVER- 5 -


X


A. uracilB. riboseC. proteinD. phosphate

________________________________________________

12. Which of the following is a product of the hydrolysis of DNA?

A. waterB. riboseC. nucleotidesD. an amine group

13. What type of chemical bond is broken during the first step of replication?


14. What is the production of mRNA called?

A. mutationB. translationC. replicationD. transcription

- 6 -



AAUAAC

AAAAAG

Asparagine

Lysine

CAUCAC

CAACAG

Histidine

Glutamine

GAUGAC

GAAGAG

Aspartic acid

Glutamate

UAUUAC

UAAUAG

Tyrosine

Stop

AGUAGC

AGAAGG

Serine

Arginine

UGUUGC

UGAUGG

Cysteine

StopTryptophan

AUUAUCAUA

AUG

Isoleucine

Methionine

UUUUUC

UUAUUG

Phenylalanine

Leucine

ACUACCACAACG

Threonine

CCUCCCCCACCG

Proline

GCUGCCGCAGCG

Alanine

UCUUCCUCAUCG

Serine

CGUCGCCGACGG

Arginine

GGUGGCGGAGGG

Glycine

CUUCUCCUACUG

Leucine

GUUGUCGUAGUG

Valine

15. What is a base sequence for a section of DNA which codes for the amino acids serineand arginine?

A. A G C A G AB. A G T G C TC. A G U A G AD. U C A U C U

________________________________________________

16. What molecule does the word “mosaic” refer to in the fluid-mosaic model of cell-membranestructure?

A. proteinB. glycogenC. cholesterolD. phospholipid

17. What is the diffusion of water across a selectively-permeable membrane called?

A. osmosisB. pinocytosisC. endocytosisD. active transport

OVER- 7 -

18. Which of the following would result in the greatest rate of diffusion of particlesacross a membrane?

A. small particles at 10 C∞B. large particles at 20 C∞C. large particles at 30 C∞D. small particles at 40 C∞


19. What is the process illustrated in the diagram above?

A. hydrolysisB. exocytosisC. pinocytosisD. phagocytosis

________________________________________________

20. What happens to an animal cell when it is placed in a hypertonic solution?

A. lysisB. crenationC. plasmolysisD. increased turgor

21. The secretion of thyroxin would trigger which of the following effects?

A. an increase in ATP productionB. a decrease in the speed of nerve impulse transmissionC. an increase in the amount of glycogen present in the liverD. a decrease in the amount of sodium re-absorbed into the blood

- 8 -


Temperature( ∞C) pH Substrate

W 37 2.0 protein

X 37 8.0 starch

Y 70 7.4 dipeptides

Z 15 2.0 protein

22. During which of the conditions above would pepsin function optimally?

A. WB. XC. YD. Z

________________________________________________

23. Which structure is not part of the pathway that food follows on its way through thedigestive tract?

A. pharynxB. duodenumC. gall bladderD. cardiac sphincter

OVER- 9 -


X

24. What is a function of the secretions produced by structure X?

A. to increase the surface area of fatsB. to decrease the pH of the stomachC. to break down proteins to peptidesD. to break down glycogen to maltose

- 10 -


UV

W

X

Y

Z

25. Which structures produce secretions which aid in the digestion of proteins?

A. U, YB. V, WC. Y, ZD. X, V

26. Which structures produce secretions which aid in the digestion of carbohydrates?

A. U, VB. U, YC. W, VD. X, Z

________________________________________________

27. How would digestion be affected if liver secretions were unable to enter the duodenum?

A. The rate of emulsification would increase.B. The breakdown of maltose would increase.C. There would be less amino acid production.D. The rate of fatty acid production would decrease.

OVER- 11 -

28. Which of the following is a result of the low pH of the stomach?

A. the production of vitamin KB. the activation of trypsinogenC. the break down of starch to maltoseD. the conversion of pepsinogen to pepsin


W

X

Y

Z

29. Where does the absorption of amino acids take place?

A. WB. XC. YD. Z

________________________________________________

30. Which characteristics of the digestive system increase its surface area?

A. E. coli, bile and villiB. villi, ridges/folds and lengthC. sphincters, peristalsis and epiglottisD. intestinal glands, gastric glands and ridges/folds

- 12 -

31. Which blood vessels carry blood to and from the legs?

A. iliac arteries and veinsB. renal arteries and veinsC. hepatic vein and posterior vena cavaD. mesenteric arteries and hepatic portal vein


X

32. What is the function of structure X?

A. to carry oxygenated blood to the body from the heartB. to return oxygenated blood to the heart from the lungsC. to carry deoxygenated blood to the lungs from the heartD. to return deoxygenated blood to the heart from the body

33. Which blood vessel is not shown in the diagram?

A. the aortaB. the coronary arteryC. the anterior vena cavaD. the posterior vena cava

OVER- 13 -


X

34. What is the blood vessel labelled X?

A. the renal veinB. the hepatic veinC. the mesenteric arteryD. the hepatic portal vein

- 14 -


Y

ZX

35. What would be a result of structure Y remaining functional after birth?

A. Blood would flow from the left ventricle to the right ventricle.B. The levels of oxygen in structure Z would be lower than normal.C. The levels of carbon dioxide in structure X would be lower than normal.D. Blood in the left atrium would have higher concentrations of oxygen than

blood in the right atrium.

36. What are the functions of each type of cell shown?

A. to carry oxygen to carry carbon dioxide

B. to fight infection to engulf bacteria

C. to make antibodies to fight infection

D. to transport hydrogen ions to engulf bacteria

OVER- 15 -

37. What causes materials to move from the blood to the tissues at the arterial end of thecapillary bed?

A. osmosisB. blood pressureC. active transportD. facilitated transport

38. What is the last heart chamber that blood passes through on its way to the systemic system?

A. left atriumB. right atriumC. left ventricleD. right ventricle

39. Which heart structure is not functioning properly if an electrical device is needed to stimulatethe atria to contract?

A. septumB. SA nodeC. AV nodeD. chordae tendineae

40. What is the function of the Purkinje fibres?

A. to cause atrial contractionB. to act as a pacemaker and initiate the heartbeatC. to prevent the valves from inverting during heartbeatD. to conduct impulses from the AV node to the ventricles

41. Where are the pleural membranes found?

A. in both bronchiB. inside the alveoliC. surrounding all cellsD. lining the thoracic cavity

- 16 -


Z

W

X

Y

42. Which structure is capable of constricting and dilating as a result of the contraction of thesurrounding smooth muscle?

A. WB. XC. YD. Z

OVER- 17 -


W

X

Y

Z

43. Which of the following indicates the site of external respiration?

A. WB. XC. YD. Z

- 18 -


Lung volume

Time

Change in lung volume over time

lung volume(ml)

W X Y Z

44. When does the diaphragm contract during breathing?

A. W Æ XB. X Æ ZC. X Æ YD. Y Æ Z

________________________________________________

45. Which structure has rings of cartilage?

A. the tracheaB. the epiglottisC. the diaphragmD. the bronchioles

OVER- 19 -

46. Which graph shows the changes that occur in oxygen and carbon dioxide concentrations in theblood during external respiration?

A.

Bloodconcentrationat the alveoli

Time

O2

CO2

B.


Time

CO2

O2

C.


Time

CO2

O2

D.


Time

O2

CO2

- 20 -

47. How does a neuron respond to a strong stimulus?

A. It produces a larger action potential.B. It causes more action potentials in a given period of time.C. It causes action potentials to be conducted down the neuron at a faster rate.D. It causes more ions to cross the neuron membrane during the action potential.

48. What is the pathway of an impulse in a reflex arc?

A. from the brain to the interneuron, then to the sensory neuronB. from the motor neuron to the brain, then to the sensory neuronC. from the motor neuron to the interneuron, then to the sensory neuronD. from the sensory neuron to the interneuron, then to the motor neuron

49. What type of cell is found only in the central nervous system?

A. receptorB. interneuronC. motor neuronD. sensory neuron

50. Which part of the nervous system functions to lower blood pressure and heart rate after afrightening experience?

A. a reflex arcB. the somatic systemC. the sympathetic systemD. the parasympathetic system

51. Which of the following occurs during increased acetylcholine secretion?

A. bronchioles dilateB. increase in blood pressureC. decrease in intestinal activityD. conversion of glucose to glycogen

OVER- 21 -


X

W

Y

Z

52. Which labelled structure is responsible for smooth and coordinated movement in the body?

A. WB. XC. YD. Z

53. Which of the following is a function of structure W?

A. solving a mathematical problemB. sweating to cool the body on a hot dayC. waking up to music from an alarm clockD. sneezing when an irritant enters the nose

________________________________________________

54. How does the hypothalamus control the secretion of hormones from the anterior pituitary?

A. It sends impulses to the anterior pituitary by way of nerve cells.B. It sends neurotransmitter chemicals along axons to the anterior pituitary.C. It produces releasing hormones which are delivered to the anterior pituitary along axons.D. It produces releasing hormones that are transported to the anterior pituitary through the blood.

- 22 -

55. What structure stores urine?

A. the ureterB. the urethraC. the renal medullaD. the urinary bladder

56. What organ removes urea from the blood and reabsorbs glucose and amino acids?

A. the liverB. the kidneyC. the pancreasD. the adrenal gland

Use the following list of substances to answer question 57.

waterureaglucoseuric acidlarge proteinshydrogen ionsred blood cells

57. How many of these substances are normally found in urine?

A. 3B. 4C. 5D. 6

________________________________________________

58. What part of the kidney filters blood plasma, selectively re-absorbs salt and excretespotassium ions?

A. the nephronB. the glomerulusC. the renal pelvisD. the renal medulla

OVER- 23 -

59. Which of the following surrounds the glomerulus?

A. the afferent arterioleB. the Bowman’s capsuleC. the peritubular capillariesD. the proximal convoluted tubule

60. Inhibition of sodium reabsorption could lead to an increase in the excretion of whichof the following?

A. waterB. glucoseC. proteinsD. red blood cells

61. Through which structure do sperm travel after leaving the vas deferens?

A. the urethraB. the epididymisC. the prostate glandD. the seminiferous tubules

62. Which of the following is a function of the seminal vesicles?

A. to carry semen to the urethraB. to produce releasing hormonesC. to add secretions to the seminal fluidD. to provide a place for sperm to mature

- 24 -


X

Y

ZW

63. Which structure contains many mitochondria which provide energy for the cell to move?

A. WB. XC. YD. Z

________________________________________________

64. Secretions from which of the following controls the production of testosterone?

A. the prostate glandB. the seminiferous tubulesC. the anterior pituitary glandD. the posterior pituitary gland

OVER- 25 -


Time

X

65. Which substance causes the development of structure X?

A. estrogenB. luteinizing hormoneC. follicle-stimulating hormoneD. human chorionic gonadotropin

________________________________________________

66. The secretory phase of the uterine cycle is primarily the result of increased secretions by the

A. follicle.B. endometrium.C. corpus luteum.D. posterior pituitary.

67. Which of the following would be a result of increased levels of HCG in the blood?

A. Menstruation would occur.B. Ovulation would not occur.C. There would be a decrease in the amount of progesterone secreted.D. There would be an increase in the concentration of follicle-stimulating hormone in the blood.


- 26 -






1. Describe four different functions of proteins found in the cell membrane. (4 marks)

OVER- 27 -

2. Explain how the following are involved in protein synthesis. (2 marks: 1 mark each)

nucleolus:

enzymes:

- 28 -

Use the following data to answer question 3.

0.3

0.9

1.3

2.4

0.3

0.9

1.3

1.3

Amount ofsubstrate

(g)

Rate of productproduction

(g/min)

3.5 1.3

3. In an enzyme-catalyzed reaction, the amount of substrate was measured and compared tothe rate of product production. The data is shown above.

a) Graph the data. (Plot the amount of substrate [independent variable] on the x-axis.)(2 marks)

Rate of product production vs. Amount of substrate

OVER- 29 -

b) Explain the observed results. (2 marks)

c) Suggest a way to increase the rate of product production for substrate amountsgreater than 3.5 grams. (1 mark)

- 30 -

4. Explain how a damaged AV valve on the left side of the heart could cause fluids to build upin the lung tissues. (4 marks)

OVER- 31 -

5. a) Explain why the knee-jerk reflex still functions in a person with a severed spinal cord.(1 mark)

b) Why is there is no sensation of the stimulus? (1 mark)

- 32 -

6. Explain how ADH secretion affects the composition of the blood. (3 marks)

- 33 -

7. Describe how the secretion of testosterone is regulated in males. (3 marks)

END OF EXAMINATION

MINISTRY USE ONLY



MINISTRY USE ONLY


MINISTRY USE ONLY

Biology 12

JANUARY 2004

Course Code = BI






END OF EXAMINATION.


Question 1:

1. .

(3)

Question 2:

2. .

(4)

Question 3:

3. .

(4)

Question 4:

4. .

(4)

Question 5:

5. .

(5)

Question 6:

6. .

(3)

BIOLOGY 12

JANUARY 2004COURSE CODE = BI


ValueSuggested





OVER- 1 -




1. Which of the following structures is composed of DNA and protein?

A. ribosomesB. Golgi bodiesC. chromosomesD. smooth endoplasmic reticulum

2. Which of the following structures is attached to the nuclear envelope?

A. Golgi bodyB. mitochondrionC. cell membraneD. endoplasmic reticulum

3. Where are the structures that distinguish rough endoplasmic reticulum from smoothendoplasmic reticulum produced?

A. in the nucleolusB. in the Golgi bodiesC. in the mitochondriaD. in the cell membrane


unit molecules

polymer

H2O +

4. Which cell structure stores substances that could produce the reaction illustrated above?

A. nucleusB. vacuolesC. lysosomesD. ribosomes

- 2 -

5. What characteristic of a water molecule accounts for its polarity?

A. its cohesivenessB. its ability to act as a solventC. its unequal sharing of electronsD. the hydrogen bonding to neighbouring water molecules

6. What is the function of a buffer?

A. to carry oxygenB. to release energyC. to catalyze a reactionD. to maintain a constant pH


WX

Y

Z

7. What structure produces substances that result in a low pH?

A. WB. XC. YD. Z

OVER- 3 -

8. What substance deactivates antigens?

A. lipidsB. proteinsC. nucleic acidsD. carbohydrates


P P P

9. What is the function of this molecule?

A. to carry codons that are complementary to DNAB. long term energy storage in the liver and musclesC. to form the main component of the phospholipid bilayerD. to release energy when the bonds between the phosphate

groups are broken


P

P

S

S

P

P

S

S

P

P

S

S

P

P

S

SAT

AT

G C

GC

X

10. Which of the following is indicated by X?

A. RNAB. a codonC. a nucleotideD. an amino acid

- 4 -

11. Which of the following is a definition of recombinant DNA?

A. plasmidsB. bacterial DNAC. DNA which has been clonedD. DNA from more than one source

12. In an experiment to determine the identity of an unknown substance, it is determined that thesample contains 12% adenine, 12% thymine, 38% cytosine and 38% guanine. What is theunknown substance?

A. ATPB. DNAC. mRNAD. nuclease

13. Which of the following differentiates DNA from RNA?

A. DNA is linear and RNA is a double helix.B. DNA has deoxyribose and RNA has ribose.C. DNA is single-stranded and RNA is double-stranded.D. DNA is produced during transcription and RNA is produced

during replication.

OVER- 5 -

Use the following chart to answer questions 14 and 15.


AAUAAC

AAAAAG

Asparagine

Lysine

CAUCAC

CAACAG

Histidine

Glutamine

GAUGAC

GAAGAG

Asparatic acid

Glutamate

UAUUAC

UAAUAG

Tyrosine

Stop

AGUAGC

AGAAGG

Serine

Arginine

UGUUGC

UGAUGG

Cysteine

StopTryptophan

AUUAUCAUA

AUG

Isoleucine

Methionine

UUUUUC

UUAUUG

Phenylalanine

Leucine

ACUACCACAACG

Threonine

CCUCCCCCACCG

Proline

GCUGCCGCAGCG

Alanine

UCUUCCUCAUCG

Serine

CGUCGCCGACGG

Arginine

GGUGGCGGAGGG

Glycine

CUUCUCCUACUG

Leucine

GUUGUCGUAGUG

Valine

14. The following is a sequence of mRNA bases:

G C U U C U C C U

What sequence of amino acids results after translation occurs?

A. arginine, serine, stopB. alanine, arginine, stopC. alanine, serine, prolineD. arginine, arginine, glycine

15. Which of the following is an anticodon of a molecule of tRNA carrying isoleucine?

A. A T AB. A U UC. T A AD. U A U

- 6 -

16. How many ribosomes are needed for the production of one polypeptide containing30 amino acids?

A. 1B. 3C. 10D. 30

17. Water molecules passing through the cell membrane is an example of which of the following?

A. osmosisB. exocytosisC. active transportD. facilitated transport

18. Which of the following would decrease the rate of diffusion of molecules across asemi-permeable membrane?

A. increasing the temperatureB. decreasing the size of the moleculesC. decreasing the concentration gradientD. increasing the size of the pores in the membrane

19. What is the role of maltase when it acts as a catalyst?

A. It denatures maltose.B. It breaks down high energy phosphate bonds.C. It increases the energy of activation required in the reaction.D. It speeds up the reaction rate without being used in the reaction.

20. How do vitamins function in cells?

A. They act as coenzymes.B. They catalyze reactions.C. They provide energy for reactions.D. They act as substrates in hydrolysis.

OVER- 7 -


A B C DE1 E2 E3

21. What would occur if a competitive inhibitor for enzyme E2 was added to the metabolicpathway above?

A. Less of D would be produced.B. Enzyme 1 would be denatured.C. There would be a decrease in B.D. There would be an increase in C.


W

XY

Z

22. What is structure Z?

A. the colonB. the stomachC. the pancreasD. the duodenum

23. What structure absorbs the products of protein digestion?

A. WB. XC. YD. Z

- 8 -

24. Which of the following is a cause of the watery feces characteristic of diarrhea?

A. increased gastric secretionsB. decreased activity of the cardiac sphincterC. decreased movement of chyme into the small intestineD. high solute concentration of the fecal material in the colon


Diagram A

X

Diagram B

25. If structure X in diagram A was not functioning properly, how would the processes in thestructure shown in diagram B be affected?

A. The absorption of fats would decrease.B. The production of lipase would increase.C. The digestion of proteins would decrease.D. The absorption of glucose would increase.

________________________________________________

26. What substance is digested by secretions released by both the salivary glands and the pancreas?

A. fatB. starchC. proteinD. maltose

OVER- 9 -

27. What is a result of increased peristalsis in the duodenum?

A. decreased production of bileB. decreased pH in the small intestineC. decreased absorption of amino acidsD. increased hydrochloric acid secretion in the stomach


Y

Z W

X

28. Where are the enzymes that break down maltose and peptides produced?

A. WB. XC. YD. Z

- 10 -


29. What is a purpose of the structure shown?

A. to store and compact fecesB. to secrete enzymes that break down starchC. to increase surface area of the small intestineD. to secrete substances that physically digest fat

________________________________________________

30. Which of the following are characteristics of the blood vessel that carries blood from thearterioles to the venules?

A. thin walls with valvesB. thin walls, one cell layer thickC. thick walls to withstand pressureD. a thick middle layer of elastic tissue

OVER- 11 -


Y

W

X

Z

31. Which structure carries oxygenated blood from the mother to the fetus?

A. WB. XC. YD. Z

32. Which structure allows blood to bypass the lungs?

A. WB. XC. YD. Z

- 12 -


ZY

X

W

33. What is the blood vessel labelled W?

A. renal veinB. iliac arteryC. carotid arteryD. hepatic portal vein

34. What is the blood vessel labelled Z?

A. aortaB. carotid arteryC. subclavian veinD. posterior vena cava

35. Which blood vessel originates from the left ventricle of the heart?

A. WB. XC. YD. Z

OVER- 13 -


36. What structures are shown in the diagram?

A. platelets and red blood cellsB. platelets and white blood cellsC. red blood cells and white blood cellsD. white blood cells and plasma proteins

________________________________________________

37. What would result if the SA node received increased stimulation by the sympatheticnervous system?

A. Heart rate and blood pressure would decrease.B. Mesenteric arteries and arterioles would dilate.C. Blood pressure and blood velocity would increase.D. Production of red blood cells and platelets would increase.

38. Which of the following describes the location and function of valves found in thecirculatory system?

A. found in capillary beds and regulate the diameter of venulesB. found in blood vessels that have low blood pressure and prevent backflow of blood

in the heartC. found in blood vessels where blood is moving the fastest and control blood entering

the capillary bedsD. found in blood vessels carrying blood away from the heart and limit high blood pressure

in tissues

- 14 -


X


A. the larynxB. the bronchusC. the epiglottisD. the bronchioles

________________________________________________

40. What would occur if the cilia in the respiratory tract were damaged?

A. Mucus would accumulate.B. The larynx would stop functioning.C. Air would become trapped in the lungs.D. The diaphragm would increase thoracic volume.

41. Which of the following occurs during internal respiration?

A. ATP is produced.B. Oxygen enters the bloodstream.C. Carbon dioxide leaves the bloodstream.D. HCO3

− (bicarbonate ions) are produced.

OVER- 15 -


capillary network of one alveolus

blood flow

blood flow

Y

Z

X

W

42. Which labelled structure contains the highest concentrations of HCO3− (bicarbonate ions)?

A. WB. XC. YD. Z

________________________________________________

43. What is transported in the blood as carbaminohemoglobin?

A. oxygenB. amino acidsC. hydrogen ionsD. carbon dioxide

44. Which of the following occurs during inhalation?

A. The rib muscles relax.B. The diaphragm contracts.C. The diaphragm becomes dome-shaped.D. Pressure in the thoracic cavity increases.

- 16 -

45. How does the formation of reduced hemoglobin have a buffering effect in the body?

A. It absorbs oxygen in the lungs.B. It forms carbaminohemoglobin in the blood.C. It forms carbaminohemoglobin in the tissue fluids.D. It reduces the concentration of hydrogen ions in the blood.

46. Why would a neuron be unable to conduct impulses if, after the passage of an action potential,the sodium-potassium pump no longer functioned?

A. Sodium ions would remain concentrated inside the axon; the outside of the axon wouldbe positive compared to the inside.

B. Potassium ions would remain concentrated inside the axon; the outside of the axon wouldbe negative compared to the inside.

C. Sodium ions would remain concentrated outside the axon; the outside of the axon wouldbe positive compared to the inside.

D. Potassium ions would remain concentrated outside the axon; the outside of the axon wouldbe negative compared to the inside.

47. How does the presence of the myelin sheath around a neuron increase the speed of impulseconduction?

A. It prevents ion exchange except at the nodes.B. It transfers ions down the length of the neuron.C. It acts as an enzyme to speed the reactions of the action potential.D. It helps to carry ions across the cell membrane during the action potential.

OVER- 17 -


XY

ZW

48. Which of the following describes the role of calcium ions during synaptic transmission?

A. They cause Y to become inactivated.B. They act as carriers to move Y toward Z.C. They cause Y to undergo endocytosis at W.D. They initiate the process that results in X moving toward W.

________________________________________________

49. Which branch of the nervous system does not have nerves which directly connect to the heart?

A. the central nervous systemB. the peripheral nervous systemC. the sympathetic nervous systemD. the parasympathetic nervous system

50. What part of the brain controls the release of hormones from the pituitary gland?

A. the thalamusB. the cerebellumC. the hypothalamusD. the medulla oblongata

- 18 -


X

W

Y

Z

51. Which part of the brain allows the sharing of sensory information from both sides of the body?

A. WB. XC. YD. Z

Use the following chart to answer questions 52 and 53.

Substances in the blood

SubstanceAmount of the

substancefiltered/day

Re-absorbed bynephron

(%)

Amount of thesubstance in the

urine/day

W 170 g 100% 0 g

X 150 L 99% 1.5 L

Y 50 g 40% 30 g

Z 700 g 98% 15 g

52. What is substance W?

A. saltB. ureaC. waterD. glucose

53. What is substance Y?

A. ureaB. waterC. glucoseD. penicillin

OVER- 19 -

54. Which of the following are located in the renal cortex?

A. the efferent arteriole and the ureterB. the Bowman’s capsule and the glomerulusC. the distal convoluted tubule and the loop of HenleD. the collecting tubule and the proximal convoluted tubule

55. Which of the following is produced by the liver as a result of the metabolism ofnitrogenous wastes?

A. ureaB. uric acidC. ammoniaD. amino acids

56. What is a function of the collecting ducts?

A. pressure filtrationB. water re-absorptionC. tubular excretion of penicillinD. receptors for the hormone insulin

57. Tubular excretion involves the addition of substances into which of the following?

A. the loop of HenleB. the Bowman’s capsuleC. the distal convoluted tubuleD. the proximal convoluted tubule

58. Which of the following receives blood from the efferent arteriole?

A. the renal veinB. the glomerulusC. the afferent arterioleD. the peritubular capillaries

59. The cells of which structure contain relatively large numbers of mitochondria?

A. the glomerulusB. the afferent arterioleC. the Bowman’s capsuleD. the proximal convoluted tubule

- 20 -

60. Which of the following results from the secretion of ADH?

Urinevolume

Concentrationof urine

A. low low

B. low high

C. high high

D. high low

61. Which of the following is an effect of an increased secretion of aldosterone on the compositionof urine?

A. Urea decreases.B. Sodium ions increase.C. Potassium ions increase.D. Hydrogen ions decrease.

62. Where does sperm production occur?

A. in the epididymisB. in the vas deferensC. in the interstitial cellsD. in the seminiferous tubules

63. Which of the following would result if fructose was not present in seminal fluid?

A. Sperm would be less motile.B. Semen would become acidic.C. Less sperm would be produced.D. Less testosterone would be secreted.

64. Reduced secretions from which structure would result in decreased breast development?

A. the endometriumB. the interstitial cellsC. the anterior pituitaryD. the posterior pituitary

OVER- 21 -

65. Which of the following is a function of estrogen?

A. to initiate menstruationB. to stimulate the posterior pituitary glandC. to cause maturation of the corpus luteumD. to initiate the growth of the endometrium


Time

X

66. What would occur as a result of structure X releasing hormones?

A. Ovulation would occur.B. The follicle would mature.C. Estrogen secretion would increase.D. The endometrium would become secretory.

________________________________________________

67. Taking birth control pills that contain estrogen and progesterone results in which ofthe following?

A. the onset of menstruationB. an increased production of luteinizing hormoneC. a decreased production of follicle-stimulating hormoneD. an increased production of human chorionic gonadotropin


- 22 -








AAUAAC

AAAAAG

Asparagine

Lysine

CAUCAC

CAACAG

Histidine

Glutamine

GAUGAC

GAAGAG

Asparatic acid

Glutamate

UAUUAC

UAAUAG

Tyrosine

Stop

AGUAGC

AGAAGG

Serine

Arginine

UGUUGC

UGAUGG

Cysteine

StopTryptophan

AUUAUCAUA

AUG

Isoleucine

Methionine

UUUUUC

UUAUUG

Phenylalanine

Leucine

ACUACCACAACG

Threonine

CCUCCCCCACCG

Proline

GCUGCCGCAGCG

Alanine

UCUUCCUCAUCG

Serine

CGUCGCCGACGG

Arginine

GGUGGCGGAGGG

Glycine

CUUCUCCUACUG

Leucine

GUUGUCGUAGUG

Valine

1. The following is a DNA base sequence:

GCA CCT ATA GGA ACC

Explain what would occur during the translation of this gene if ATA underwent a mutationand was converted to A T T . (3 marks)

OVER- 23 -

2. Compare active transport and facilitated diffusion. (4 marks)

- 24 -

3. Describe two changes that could be made to an enzyme-catalyzed reaction whichwould result in a decrease in the rate of the reaction. Explain why these changes causethe reaction rate to decrease. (4 marks)

OVER- 25 -

4. Explain how nutrients and oxygen in the blood move first into the tissue fluids,and then into the cells. (4 marks)

- 26 -

5. Explain how an action potential is passed from one neuron to another. (5 marks)

- 27 -

6. Describe how positive feedback functions in the female reproductive system. (3 marks)

END OF EXAMINATION

Version 0508.1

Biology 12

Course Code = BI

58581

AUGUST 2005

MINISTRY USE ONLY


Biology 12

AUGUST 2005

Course Code = BI

Question 1

Question 2

Question 3

Question 4

Question 5

Question 6

Question 7

(.5)0 1 2 NR

(.5)0 1 2 3 NR

(.5)0 1 2 NR

(.5)0 1 2 3 NR

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Question 1

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4

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Version 0508.1

Biology 12

Course Code = BI

58581

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MINISTRY USE ONLY MINISTRY USE ONLY

Place Personal Education Number (PEN) here. Place Personal Education Number (PEN) here.

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Question 1

Question 2

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(.5)0 1 2 NR

(.5)0 1 2 3 NR

(.5)0 1 2 NR

(.5)0 1 2 3 NR

(.5)0 1 2 3 NR

(.5)0 1 2 3 NR

(.5)0 1 2 3 NR

Question 1

(.5)0 1 2 NR

Question 1

(.5)0 1 2 NR

4

4

3

4

1. Place the stickers with your Personal EducationNumber (PEN) in the allotted spaces above.Under no circumstance is your name oridentification, other than your PersonalEducation Number, to appear on this booklet.

2. Ensure that in addition to this examinationbooklet, you have an Examination ResponseForm. Follow the directions on the front of theResponse Form.

3. Disqualification from the examination will resultif you bring books, paper, notes or unauthorizedelectronic devices into the examination room.




3. For each of the written-response questions, write your answer in ink unless otherwiseinstructed in the space provided in this booklet.


5. This examination is designed to be completed in two hours. Students may, however,take up to 30 minutes of additional time to finish.


ValueSuggested





© 2005 Province of British Columbia. All rights reserved. Page 1




1. What organelle has saccules that produce vesicles?

A. a Golgi bodyB. the nucleolusC. a mitochondrionD. the rough endoplasmic reticulum

2. Which of the following breaks down old blood cells?

A. a lysosomeB. the nucleolusC. a chromosomeD. the smooth endoplasmic reticulum

3. Organelle X produces proteins. These proteins move through organelle Y toward organelle Zwhere they are packaged. What are X, Y and Z?

Organelle X Organelle Y Organelle Z

A. ribosome mitochondrion lysosome

B. ribosome rough endoplasmicreticulum Golgi body

C. nucleolus cell membrane Golgi body

D. chromosome nucleus smooth endoplasmicreticulum

© 2005 Province of British Columbia. All rights reserved.

4. What organelle produces steroid hormones?

A. a lysosomeB. a chloroplastC. the nucleolusD. the smooth endoplasmic reticulum


Structure X Structure Y

5. Which of the following is produced by structure X and becomes a part of structure Y?

A. ATPB. vesiclesC. celluloseD. lysosomes

________________________________________________

6. What type of molecule is adenosine triphosphate (ATP)?

A. a fatB. a steroidC. a proteinD. a nucleotide



Molecules• water• glucose• phospholipid

7. How many of the molecules above are polar?

A. 0B. 1C. 2D. 3

________________________________________________

8. Which molecular property allows water to act as a solvent?

A. the lack of ionic bonds within the moleculeB. the ability to donate electrons between its atomsC. the unequal sharing of electrons between its atomsD. the presence of covalent bonds within the molecule

9. Equal quantities of four different acids were placed in separate test tubes. OH- was added

until the pH in each test tube was 3.0. The graph shows the amount of OH- added to eachtest tube.

Amount ofOH

– needed

AcidW X Y Z

Which of the four acids had the highest initial pH?

A. WB. XC. YD. Z

bjonker

Cross-Out


10. Which of the following molecules is a monomer of lipids?

A. glycerolB. glycogenC. amino acidD. cholesterol

11. Which of the following is a formula for a carbohydrate?

A. C H O2 6 2

B. C H O3 3 6

C. C H O3 8 3

D. C H O5 10 5

12. Which of the following molecules functions as a hormone?

A.

O

CH3

CH3

OHB. O O

O

C.P

O

D.C

C

C

O

O

C

H

H

C C C C H

H H H H

HH

C

H

H

C C C C H

H H H H

HH

C

H

H

O

C C C H

H H H

HHH

C

H

H

CH

H

O

OCH

OCH

H



13. Which of the following is not found in this molecule?

A. uracilB. nitrogenC. phosphateD. deoxyribose

________________________________________________

14. Which of the following is the second step of replication?

A. the formation of two new DNA moleculesB. complementary base pairing of nitrogenous basesC. the breaking of hydrogen bonds between nitrogenous basesD. the joining of bonds between the sugar and phosphate backbone



W X Y Z

15. Which of the above illustrates the result of replication?

A. WB. XC. YD. Z

16. Where does this process take place?

A. the nucleusB. the ribosomeC. the nucleolusD. the Golgi body


17. Which of the following is a step in transcription?

A. Ribosomes move along mRNA.B. Amino acids are joined by peptide bonds.C. Adenine in DNA bonds to thymine in mRNA.D. Hydrogen bonds are broken to expose a section of the DNA helix.


AU

GG

G C A CC

AA

A G U A U C

UU U

CA

U

18. The process shown includes which of the following steps?

A. denaturing of tRNAB. codon-anticodon base pairingC. joining of adjacent nucleotidesD. formation of hydrogen bonds between amino acids

19. Where in the cell does this process take place?

A. the nucleusB. the nucleolusC. the Golgi bodiesD. the rough endoplasmic reticulum

________________________________________________

20. Ultraviolet light, which can alter DNA, is an example of which of the following?

A. a mutagenB. polymeraseC. an anticodonD. recombinant DNA


21. Which property of a neutral fat allows it to diffuse through the cell membrane?

A. the size of the moleculeB. the non-polar characteristic of the moleculeC. the presence of glycoproteins in the cell membraneD. the presence of protein carriers in the cell membrane


Time

X

22. Molecule X could be which of the following?

A. waterB. glucoseC. acetylcholineD. potassium ions

________________________________________________

23. Cholesterol molecules are synthesized in liver cells and packaged as LDLs (low-densitylipoproteins). The LDLs are released into the blood. Which of the following is the processby which LDLs re-enter body cells from the blood?

A. osmosisB. exocytosisC. endocytosisD. facilitated diffusion


Use the following experiment to answer questions 24 and 25.

Experiment

A student designs an experiment to determine the effect of sucroseconcentration on the mass of potato cells. The following procedure iscarried out:

• 6 equal-sized cubes are cut from the same potato.

• The initial mass of each of the cubes is measured.

• 6 test tubes are filled with different solutions (distilled water, 1%, 2%,3%, 4% and 5% sucrose solutions)

• A single cube of potato is added to each test tube.

• After one hour the cubes are removed, blotted dry with a paper towel,and the mass of each cube is recorded.

24. One of the solutions was found to be isotonic to the cytoplasm of the potato cells.Why was there no change in the mass of the potato cube in this isotonic solution?

A. There is an equal movement of water into and out of the cells.B. The water and sucrose do not move across the cell membrane.C. There is an equal movement of sucrose into and out of the cells.D. There is an equal movement of water and sucrose into and out of the cells.

25. What is the dependent variable in the experiment?

A. the size of the potato cubesB. the mass of the potato cubesC. the concentration of the solutionD. the time the cubes remain in the test tubes



10 minuteselapsed time

26. Red blood cells are added to a salt solution in a beaker. Which of the following explains thechanges that occurred to the red blood cells after 10 minutes?

A. The red blood cells were placed in an isotonic solution.B. The red blood cells were placed in a hypotonic solution.C. The red blood cells were placed in a hypertonic solution.D. The red blood cells were hypertonic to the solution in the beaker.

________________________________________________

27. Which of the following increases the rate of diffusion in cells?

A. increased surface area to volume ratioB. decreased folding of the cell membraneC. a decrease in the concentration gradientD. an increase in temperature from 40oC to 90oC

28. Which of the following attaches to a protein to catalyze a metabolic reaction?

A. an enzymeB. a coenzymeC. a heavy metalD. a competitive inhibitor


29. A chemical reaction occurs slowly at 37∞C. When molecule X is added, the reactionspeeds up. Which of the following is a monomer of molecule X?

A.

O

CCN

H

OHR

H

H B. CH2OH

H

OH

OHH

OHHO

H H

H

O

C.

NCCCCC

HO

O

H

HHH H

HHH H

D.P

O

________________________________________________

30. Which of the following decreases the rate of an enzyme-catalyzed reaction in the body?

A. adding more enzymeB. adding more substrateC. maintaining optimum pHD. changing the temperature from 37∞C to 10∞C

31. Which pair of structures produces amylase?

A. the liver and the duodenumB. the liver and the salivary glandsC. the pancreas and the small intestineD. the salivary glands and the pancreas

32. Which pair of structures produces enzymes that digest protein?

A. the colon and the pancreasB. the stomach and the pancreasC. the small intestine and the liverD. the stomach and the large intestine


33. Which of the following may be found in a person’s stomach after they have eaten a meal?

A. water, salts, maltase and bileB. starch, glycerol, amylase and trypsinC. protein, pepsin, hydrochloric acid and maltoseD. hydrochloric acid, peptides, bicarbonate ions and nuclease

34. Which of the following results from decreased secretions from the gall bladder?

A. increased gastric secretionsB. increased peristalsis in the digestive tractC. decreased absorption of water in the small intestineD. decreased production of glycerol in the small intestine

35. What substances are absorbed by the lacteals?

A. fatsB. peptidesC. nucleotidesD. carbohydrates

36. How are veins and lymph vessels similar?

A. both contain valvesB. both return blood to the heartC. both have large amounts of elastic tissueD. both carry blood with a low oxygen concentration

37. Where is blood velocity the slowest?

A. in a veinB. in a venuleC. in an arteryD. in a capillary



X

Y

Z

W

38. Which blood vessel can constrict to cause an increase in blood pressure?

A. WB. XC. YD. Z

39. Which vessel is a venule?

A. WB. XC. YD. Z

40. Which vessel contains blood with the highest concentration of bicarbonate ions and hasthe lowest pressure?

A. WB. XC. YD. Z


41. Where does lymph enter the circulatory system?

A. at the hepatic veinB. at the jugular veinsC. at the coronary veinsD. at the subclavian veins

42. Blood enters the iliac artery from which of the following vessels?

A. the aortaB. the renal arteryC. the carotid arteryD. the coronary artery

Use the following graph to answer questions 43 and 44.

Blood pressure(mm Hg) W

Y

Distance from the heart

X

Z

43. Which letter indicates the point at which the ventricles are in systole?

A. WB. XC. YD. Z

44. Which of the following occurs at W?

A. The semilunar valves are open.B. The ventricles are filling with blood.C. The atrioventricular valves are closed.D. The Purkinje fibres stimulate the atria to contract.



X

WV

Y

U

Z

45. In which area do voice sounds originate?

A. VB. WC. XD. Y

46. What is the structure labelled W?

A. the larynxB. the alveoliC. the tracheaD. the bronchi

47. What structure prevents food from entering the respiratory system?

A. UB. XC. YD. Z


48. What occurs as the pH of the blood in muscle capillaries decreases?

A. Concentration of oxyhemoglobin increases.B. Activity in the medulla oblongata decreases.C. Concentration of reduced hemoglobin decreases.D. Concentration of oxygen in the blood plasma increases.


S

V

X

Y

Z

T

UW

49. Which letter indicates the interneuron?

A. VB. XC. YD. Z

50. Which letter indicates the dendrite of the structure which carries impulses from a pain receptor?

A. SB. TC. UD. W

51. Which structure carries impulses away from the central nervous system?

A. UB. VC. WD. Z

bjonker

Cross-Out


52. What part of the brain controls the release of hormones from the pituitary gland?

A. the thalamusB. the cerebrumC. the hypothalamusD. the corpus callosum

53. Which of the following would require the greatest activity in the cerebellum?

A. recalling a memoryB. smelling freshly baked breadC. adding numbers in your headD. performing a gymnastics routine

54. What part of the brain receives sensory information and sends it to the appropriate areasof the cerebrum?

A. the thalamusB. the cerebellumC. the hypothalamusD. the corpus callosum

55. To what part of the kidney is the ureter attached?

A. the nephronB. the renal pelvisC. the renal cortexD. the renal medulla



W

Y

Z

X

56. What area of the kidney has the highest concentration of sodium ions and urea?

A. WB. XC. YD. Z


W

X

Y

Z

57. How many of the labelled structures allow water reabsorption?

A. 1B. 2C. 3D. 4


58. In what part of the nephron does glucose move from the filtrate to the surroundingblood vessels?

A. the loop of HenleB. the Bowman’s capsuleC. the distal convoluted tubuleD. the proximal convoluted tubule


• ions• water• lipids

• protein• blood cells• amino acids

59. How many of the above items pass from the bloodstream into Bowman’s capsule?

A. 2B. 3C. 4D. 5



W

Y

Z

X

60. Which gland releases a hormone that causes the reabsorption of sodium ions?

A. WB. XC. YD. Z

________________________________________________

61. Where do sperm become motile?

A. the epididymisB. the vas deferensC. the prostate glandD. the seminal vesicles



X

Y

62. Which of the following is a function of the substance produced at Y?

A. to fertilize the eggB. to neutralize the acidity of the vaginaC. to provide nourishment for the spermD. to increase muscular development at puberty

63. Where do the cells stored in X move to next?

A. the urethraB. the epididymisC. the vas deferensD. the seminal vesicles

________________________________________________

64. Which of the following is a function of seminal fluid?

A. to provide nutrition for the eggB. to cause contraction of the uterusC. to act as an acid to buffer the vaginaD. to develop secondary sexual characteristics


65. Which of the following hormones acts on the testes?

A. ADHB. GnRHC. luteinizing hormoneD. human chorionic gonadotropin

66. Which of the following is a consequence of increased secretions of progesterone?

A. the release of the ovaB. the maturation of the follicleC. a decrease in luteinizing hormoneD. an increase in follicle-stimulating hormone

67. Which of the following occurs during days 15–28 of the ovarian cycle?

A. The follicle undergoes maturation.B. A luteinizing hormone surge occurs.C. Progesterone is secreted by the corpus luteum.D. Secretion of follicle-stimulating hormone begins.








1. A person is diagnosed with hypothyroidism, a condition in which an insufficient amountof thyroxin is present in the bloodstream. Explain how the breathing rate is affectedby the decreased secretion of thyroxin. (2 marks)


2. Using two examples, explain why correct pH is important for the efficient functioningof digestive enzymes. (4 marks)

3. How does the chemical composition of the blood in the aorta differ from that of the blood inthe pulmonary trunk? (4 marks)


4. Explain three ways in which the alveoli are well suited to their function. (3 marks)

5. Describe the upswing and downswing of an action potential with respect to membranepolarity and movement of ions. (4 marks: 2 marks each)

upswing:

downswing:


6. Explain how the conditions in the renal medulla result in the production of urine which ishypertonic to blood. (3 marks)

7. Describe the events which initiate and control the secretion of oxytocin. (3 marks)

END OF EXAMINATION

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