GRADE 11 NOVEMBER 2015 LIFE SCIENCES P1...NATIONAL SENIOR CERTIFICATE GRADE 11 NOVEMBER 2015 LIFE...

NATIONAL SENIOR CERTIFICATE

GRADE 11

NOVEMBER 2015

LIFE SCIENCES P1

MARKS: 150 TIME: 2½ hours

This question paper consists of 14 pages.

2 LIFE SCIENCES P1 (EC/NOVEMBER 2015)

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1. Answer ALL the questions in the ANSWER BOOK. 2. Start EACH question on a NEW page. 3. Read ALL the questions correctly and answer only what is asked. 4. Number the answers correctly according to the numbering system used in

this question paper.

5. Non-programmable calculators may be used. 6. Show ALL your calculations, including units and formula, where applicable. 7. Write neatly and legibly.

(EC/NOVEMBER 2015) LIFE SCIENCES P1 3


SECTION A QUESTION 1 1.1 Various options are provided as possible answers to the following

questions. Choose the correct answer and write only the letter (A to D) next to the question numbers (1.1.1–1.1.10) in the ANSWER BOOK, for example 1.1.11 A.

1.1.1 If a drop in the pH of the blood occurs, the kidneys will … A increase the absorption of urea. B decrease the absorption of sodium ions. C decrease the secretion of hydrogen ions. D increase the re-absorption of bicarbonate ions. 1.1.2 Which of the following will cause the kidneys to reabsorb more

sodium ions? A A decrease in blood pressure B An increase in the volume of blood C Constriction of the afferent arterioles D A decrease in the amount of ADH secreted 1.1.3 Cilia are found lining which of the following structures? A Larynx B Alveoli C Trachea D Pleural membranes 1.1.4 Which of the following takes place in the cytoplasm of a plant cell

but not in the mitochondria? A Oxidative phosphorylation B Krebs cycle C Glycolysis D Light dependent reactions of photosynthesis 1.1.5 The conversion of pyruvic acid into lactic acid occurs during ... A photolysis. B glycolysis. C anaerobic respiration. D oxidation of glucose.



1.1.6 Which of the following substances can be absorbed by blood

without further digestion? A Fats B Proteins C Starch D Glucose 1.1.7 Which of the following survival curves represents a troop of

baboons?

1.1.8 Fecundity is... A the average number of children born in one generation per

female of child bearing age. B the actual number of children born in one generation per

female of child bearing age. C the average number of children born per 10 000 females of

child bearing age. D the average number of children born in one generation per

females aged between 45 and 55 years. 1.1.9 The resource partitioning observed in an ecosystem effectively

reduces ... A the ability of closely related species to interbreed. B competition between closely related species by reducing

overlap of ecological niches. C predatory instinct of related species. D the wastage of food resources. 1.1.10 Which of the following represents the characteristic feature of

developing Countries such as Ethiopia, Mexico and Thailand? A Highly industrialised B High birth rates C Longer life expectancy D Low infant mortality rates (10 x 2) (20)



1.2 Give the correct biological term for each of the following descriptions.

Write only the term next to the question number (1.2.1–1.2.6) in the ANSWER BOOK.

1.2.1 The pigment which is responsible for absorbing radiant energy

during photosynthesis 1.2.2 Expected colour change of diluted iodine solution when the

presence of starch in leaf is confirmed 1.2.3 Genetic material found in the mitochondrial matrix 1.2.4 The gas which is essential for the Kreb’s cycle to occur 1.2.5 Folded structures found on the inner membrane of a mitochondria 1.2.6 Stage of aerobic respiration that releases carbon dioxide (6 x 1) (6) 1.3 Indicate whether each of the statements in COLUMN Ι applies to A only,

B only, both A and B or none of the items in COLUMN ΙΙ. Write A only, B only, both A and B, or none next to the question number (1.3.1–1.3.6) in the ANSWER BOOK.

COLUMN Ι COLUMN ΙΙ 1.3.1 Molecule that stores energy A. ATP

B. ADP 1.3.2 The fuel required for cellular respiration A. Glycogen

B. Glucagon 1.3.3 Products of anaerobic respiration in yeast A. Alcohol

B. CO2 1.3.4 The organelle in which photosynthesis takes

place A. Mitochondria B. Chloroplast

1.3.5 Storage of chlorophyll A. Grana B. Lamella

1.3.6 Acid secreted in the stomach during digestion

A. HCl B. Fatty acid

(6 x 2) (12)



1.4 Study the longitudinal section through the human kidney and answer the

questions that follow.

1.4.1 Label parts A, B and C. (3) 1.4.2 Which labelled part becomes a site of obstruction to the flow of

urine when a pellet of renal stone is dislodged? (1) 1.4.3 State the NAME and LETTER of the blood vessel that contain

higher percentage of waste products. (2) 1.4.4 Which one of the labelled blood vessels has the lowest blood

pressure? (1) 1.5 Study the following passage on obesity and answer questions. Obesity can be described as an imbalance between energy intake and

expenditure such that excess energy is stored in fat cells, which enlarge or increase in number. In a sample of 7 726 South African women aged 15–95 years old, black women had the highest prevalence of overweight and obesity (58,5%), followed by women of mixed ancestry (52%), white women (49,2%) and then Indian women (48,9%). A different pattern was seen in men. In a sample of 5 401 South African men aged 15–95 years, the prevalence of overweight and obesity was highest in white men (54,5%), followed by Indian men (32,7%) and men of mixed ancestry (31%), with the lowest prevalence in African men (25%). Some of the health risks associated with obesity are diabetes, coronary heart disease, hypertension, cancer and psychological ill health.

Source: http://www.mrc.ac.za/chronic/cdlchapter7.pdf 1.5.1 What is main cause for obesity? (2) 1.5.2 What is the total number of people sampled during this survey? (1) 1.5.3 What could be the possible reason for the different prevalence of

obesity between men and women? (1) 1.5.4 Name ONE of the health risks mentioned in the extract that has the

potential of causing stroke. (1) TOTAL SECTION A: 50

A

B

C

D

E

http://www.mrc.ac.za/chronic/cdlchapter7.pdf



SECTION B QUESTION 2 2.1 Study the Age-gender pyramids representing two different countries and

answer the questions that follow.

2.1.1 Name the source of information required to plot the above graph. (1) 2.1.2 Which population pyramid (A or B) shows an increasing

population? (1) 2.1.3 Explain your response to QUESTION 2.1.2. (4) 2.1.4 Describe the trend of population growth in Graph A. (3) 2.1.5 Does graph A represent increasing, declining or stable population? (1)



2.2 Learners at a certain school conducted an investigation to study the

communal interaction between two different species in a particular ecological niche.

The investigation was set up as follows: x Populations of two different species of Tribolium (a flour beetle) were

kept in six different bottles of flour numbered 1–6 as shown in the diagram below. (The bottles of flour served as food and habitat).

x Each bottle contained approximately 100 beetles of each species. x Each bottle was kept under different temperatures and humidity

conditions:

x After a period of time the number of each species surviving in each of

the bottles was determined and the results were recorded. The results are shown below:

Bottle Temperature (°C)

Relative humidity

(in %)

No: of T. castaneum

surviving

No. of T. confusum

surviving 1 34 70 100 0 2 34 30 10 90 3 29 70 86 14 4 29 30 13 87 5 24 70 29 70 6 24 30 0 100 2.2.1 Define the following terms: (a) Community (2) (b) Ecological niche (2) 2.2.2 Which one of the species is more tolerant to low temperature and

low humidity? State a reason for your answer. (2) 2.2.3 Are the factors being investigated density-dependent or density

independent? (1) 2.2.4 From the above results, what deduction can be made with regards

to the type of competition which has occurred? (1)



2.3 Study the graph showing the growth of human population and answer

questions:

2.3.1 What kind of growth form is followed by the humans? (1) 2.3.2 Which phase of growth form mentioned in the above question is

represented from 1930 to 1999? (1) 2.3.3 Explain why the stage of population growth depicted from 1930 to

1999 has occurred. (4) 2.3.4 Give any TWO reasons for the slow population growth from 1999 to

2015. (2) 2.3.5 Read the extract below and answer questions Current global population of over 7 billion is already two to three

times higher than the sustainable level. Several recent studies show that Earth’s resources are enough to sustain only about 2 billion people at a European standard of living.

http://www.worldpopulationbalance.org/3_times_sustainable (a) Predict the fate of humans if the current trend of population

growth is sustained without check. (1) (b) Suggest a practical solution to reduce the accelerated growth

of human population. (1)

0500

100015002000250030003500400045005000550060006500700075008000

1650 1850 1930 1975 1999 2015

Popu

latio

n si

ze in

mill

ions

Time in years

Growth of human population from 1650 to 2015

http://www.worldpopulationbalance.org/3_times_sustainable

http://www.worldpopulationbalance.org/3_times_sustainable



2.4 An experiment was conducted to determine whether light is necessary for

photosynthesis. The procedure followed was given below: x A geranium potted-plant was destarched

x A cross-shaped light-slit was cut out on an aluminium foil x The aluminium foil stencil was then clipped on to one of the destarched

leaves as shown in the diagram below x The potted plant was exposed to bright sunlight for 4–5 hours x After 5 hours, the aluminium foil stencil was removed and the leaf was

tested for starch

2.4.1 How was the plant de-starched? (1) 2.4.2 Explain why all the starch have disappeared during the process

mentioned in QUESTION 2.4.1. (4) 2.4.3 Describe various steps that were followed during a starch test in

the correct sequence. (4) 2.4.4 Draw a labelled diagram of leaf showing the result of the

investigation. Use a lead pencil and shade the parts which tested positive for starch. (3)

[40]



QUESTION 3 3.1 The diagram shows a plant propagator in which scientists can control

temperature, light intensity and carbon dioxide concentration:

x The scientists set different temperature, CO2-concentration and light

intensity for four lettuce plants. x The graphical of illustration of the results are given below. x Mean mass of lettuce plants serves as an indication of rate of

photosynthesis. Study the results given below and answer the following questions: Results of the investigation



3.1.1 What is the influence of light intensity on mean mass of lettuce

plants? (2) 3.1.2 Name the TWO limiting factors that influence the photosynthesis as

the light intensity increases. (2) 3.1.3 How did the scientists able to increase the rate of photosynthesis to

the maximum level? (3) 3.1.4 What would happen to the rate of photosynthesis if the temperature

is raised beyond 35 °C? Give a reason for your answer. (2) 3.2 The diagram below shows parts of human digestive system. Study the

diagram and answer questions.

3.2.1 Label parts labelled A, B and D. (3) 3.2.2 State the name and letter of a gland that secretes digestive juice

containing no enzymes. (2) 3.2.3 State any FOUR functions of the digestive juice released from part

labelled D. (4) 3.2.4 Name the chronic health risk caused by the malfunctioning of part

labelled B. (1) 3.2.5 Briefly describe the homeostatic role of part labelled B when the

blood sugar level rises in the human body. (8)



3.3 The diagram below shows the structure of a malpighian corpuscle. Study

the diagram and answer the questions that follow.

3.3.1 Name parts labelled A, B and C. (3) 3.3.2 Which physiological process takes place in the diagram shown in

the above diagram? (1) 3.3.3 Explain how the difference in diameter of the parts labelled A and

B is responsible for the process that occurs in the malpighian body. (6)

3.3.4 Name the specialised cells found at D. (1) 3.3.5 Describe how these cells mentioned in QUESTION 3.3.4 are

structurally suited for their function. (2) [40] TOTAL SECTION B: 80



SECTION C QUESTION 4 Describe the mechanism of the breathing process and explain how the correct level of respiratory gases are restored soon after running a 100 m sprint.

Content: 17 Synthesis: 3

TOTAL SECTION C: 20 GRAND TOTAL: 150

NATIONAL SENIOR CERTIFICATE

GRADE 11

NOVEMBER 2015

LIFE SCIENCES P1 MEMORANDUM

MARKS: 150

This memorandum consists of 7 pages.



SECTION A QUESTION 1 1.1 1.1.1 D 33 1.1.2 A 33 1.1.3 C 33 1.1.4 C 33 1.1.5 C 33 1.1.6 D 33 1.1.7 D 33 1.1.8 A 33 1.1.9 B 33 1.1.10 B 33 (10 x 2) (20) 1.2 1.2.1 Chlorophyll 3 1.2.2 Blue-black 3 1.2.3 Deoxyribonucleic acid/DNA 3 1.2.4 Oxygen 3 1.2.5 Cristae 3 1.2.6 Kreb’s cycle 3 (6 x 1) (6) 1.3 1.3.1 A only 33 1.3.2 None 33 1.3.3 Both A and B 33 1.3.4 B only 33 1.3.5 Both A and B 33 1.3.6 A only 33 (6 x 2) (12) 1.4 1.4.1 A - Renal capsule 3 B - Collecting tubules 3 C - Ureter 3 (3) 1.4.2 Ureter/C 3 (1) 1.4.3 Renal artery 3 - D3 (2) 1.4.4 E or Renal vein 3 (1) 1.5 1.5.1 Obesity is an imbalance between energy intake and

expenditure 3 such that excess energy is stored in fat cells which enlarge/ increase in number 3 (2)

1.5.2 13 127 3 (1) 1.5.3 Men are physically more active than women 3 (1) 1.5.4 Hypertension 3 (1) TOTAL SECTION A: 50



SECTION B QUESTION 2 2.1 2.1.1 Census 3 (1) 2.1.2 B 3 (1) 2.1.3 The base of the age pyramid is wide but it narrows towards the

top. 3 This indicates a high proportion of individuals in the younger age

group. 3 When they grow up and reproduce the population will increase in size. 3 The narrowing of the pyramid towards the top also indicates a high death rate with increasing age. 3 (4)

2.1.4 The population size at each of the age groups remains almost

equal. 3 This indicates that the birth and death rates are almost the same. 3 Therefore, the population will remain more or less the same. 3 (3)

2.1.5 Stable population 3 (1) 2.2 2.2.1 (a) Community

A community consists of populations of different species 3 that live and interact in the same place 3 at the same time. 3 (2)

(b) Ecological niche The ecological role of a species3 within the structure and function of a community. 3 (2)

2.2.2 Tribolium confusum 3

100 survived in bottle 6 when the temperature was 24 °C and the relative humidity was 30%. 3 (2)

2.2.3 Density independent factors 3 (1) 2.2.4 Since there are two different species involved it can be regarded

as an interspecific competition. 3 (1) 2.3 2.3.1 Exponential/Geometric/J-shape growth form 3 (1) 2.3.2 Accelerated/ exponential growth phase 3 (1) 2.3.3 x Increases in food production and distribution3

x Improvement in public health (water and sanitation)3 x Advancement in medical technology (antibiotics and

vaccines)3 x Education and awareness leading to more health conscious

population3 (4)



2.3.4 The human population has almost reached the carrying capacity

of the planet earth and therefore begin to experience environmental resistance such as: x Competition for food, water and living space leading to war

and crime rate escalate.3 x New diseases3 (e.g. HIV and Aids; Ebola, etc.) x Greater awareness and education 3 (Any 2 x 1) (2)

2.3.5 (a) Might lead to extinction of human species (1)

(b) x Educate and organise awareness programmes to highlight the consequences of unchecked population growth3

x Tax incentives for smaller families3 x Introduction of family planning programmes3(Any 1 x 1) (1)

2.4 2.4.1 The plant was placed in a dark box/darkroom for at least 48

hours. 3 (1) 2.4.2 x In the dark box, the potted plant was not exposed to sun

light 3 x and therefore, no photosynthesis takes place. 3 x In the absence of photosynthesis, no glucose will become

available as a source of energy. 3 x Therefore, the plant starts converting stored starch in to

glucose continuously until it is no longer present. 3 (4) 2.4.3 x Boil the leaf in water for 3–4 minutes. 3

x Boil the leaf in alcohol for about 2 minutes. 3 x Rinse the leaf in cold water. 3 x Spread the leaf on a tile and add few drops of diluted iodine

solution. 3 2.4.4

(3) [40]



QUESTION 3 3.1 3.1.1 The rate of photosynthesis increases 3 as the light intensity

increases 3 therefore, the mean mass of lettuce plants increase. 3 (Any 2 x 1) (2)

3.1.2 Carbon dioxide 3

Temperature 3 (2) 3.1.3 They raised the level of CO2 to an optimum level of 4% 3 and

temperature to 25 °C 3 as they increased the light intensity to 8 arbitrary units. 3 (3)

3.1.4 x The rate of photosynthesis will drop 3 drastically

x because at higher temperature the protein molecules of the enzymes become denatured 3

x and therefore, become functionless. 3 (2) 3.2 3.2.1 A Stomach3

B Pancreas 3 D Gall bladder 3 (3)

3.2.2 Name: Liver 3

Letter: C 3 (2) 3.2.3 x Neutralises the acidic chyme from the stomach 3

x Emulsifies fat 3 x Provides an alkaline pH for the functioning of enzymes

found in the pancreatic juice 3 x Acts an antiseptic and prevents decomposition of food 3 (4)

3.2.4 Diabetes mellitus 3 (1) 3.2.5 When the blood sugar level rises:

x (Beta cells) of the islets of Langerhans 3 in the pancreas 3 secrete insulin 3 which regulates blood sugar level.

x It facilitates absorption of glucose from blood into the cells and glucose level of blood is lowered. 3

x It increases the rate of glucose utilisation in cells. 3 x It stimulates the conversion of excess glucose into

glycogen in the liver and muscles. 3 (max 4) When the blood sugar level drops:

x (Alpha cells) of the islets of Langerhans in the pancreas secrete glucagon 3 which regulates blood sugar level.

x It stimulates the conversion of stored glycogen into glucose. 3

x and increases the level of glucose in the blood. 3 High concentration of glucose inhibits the secretion of glucagon3 but stimulates the secretion of insulin.3 Similarly, low concentration of glucose inhibits the secretion of insulin3 but stimulates the secretion of glucagon.3 This is known as negative feedback mechanism.3 (max 4) (8)



3.3 3.3.1 A Afferent arteriole 3

B Efferent arteriole 3 C Glomerulus 3 (3)

3.3.2 Ultra-filtration 3 (1) 3.3.3 Part labelled B is narrower than part labelled A. 3 Narrow

diameter of part labelled B therefore, resist the flow of blood by slowing down the rate of blood flow. 3 This creates higher blood pressure 3 in part labelled C. High blood pressure thus generated leads to leakage of blood plasma 3 with smaller substances such as glucose, amino acids, water, urea and other nitrogenous waste products through the micro pores 3 on the capillary network at C. Blood cells, plasma proteins and other large solutes are left behind in blood. 3 (6)

3.3.4 Podocytes 3 (1) 3.3.5 Presence of slit pores 3 between the podocytes act as selective

filters 3 allowing only fairly small particles to pass through into the capsular space. 3 (Any 2 x 1) (2)

[40] TOTAL SECTION B: 80

SECTION C QUESTION 4 Mechanism of breathing process Inhalation (Inspiration) x Diaphragm contracts and becomes less convex 3 x Abdominal muscles relax 3 x External intercostals muscle contract3internal intercostal muscle relax 3 x Ribs are raised upwards and outwards 3 x Thoracic cavity enlarges in volume 3 x and pressure in lungs decreases 3 x Air flows through the air passages into lungs 3 x Lungs expand 3 (max 5) (5) Exhalation (Expiration) x Diaphragm relaxes3 and return to its convex dome-shaped position3 x External intercostals muscles relax3 and internal intercostals contract3 x Ribs and sternum move inwards and downwards3 x Volume of thoracic cavity decreases3 x Pressure inside thoracic cavity increases3 x Pressure on lungs increases3 and x air rich in carbon dioxide is forced out of lungs 3 through the air passages

into atmosphere 3 (max 5) (5)



Homeostatic control of carbon dioxide and oxygen x When the carbon dioxide concentration in the blood increases 3 x it is detected by the sensory cells (pH receptors) in the walls of the aorta

near the heart and brain 3 x and at the base of the carotid arteries 3 and x afferent sensory impulses are transmitted 3 x to the respiratory control centre in the medulla oblongata 3 x and the cardio-vascular centre 3 x from where efferent impulses are transmitted to the diaphragm 3 x and external inter-costal muscles 3 x which contract more actively to increase the rate and depth of breathing 3 x as a result, more oxygen is inhaled 3 and x more carbon dioxide is exhaled 3 x the cardiac muscles contract faster 3 (heart beat rate increases) x and the carbon dioxide containing blood is pumped faster to lungs 3 x and oxygen containing blood faster to the tissue cells 3 x the peripheral arterioles contract 3 x so that the blood flows faster through the tissues 3 x when the carbon dioxide concentration decreases the process slows

down 3 (max 7) (7) Assessing the presentation of the essay

Criterion Relevance (R)

Logical sequence (L)

Comprehensive (C)

Generally All information provided is relevant to the topic.

Ideas are arranged in a logical/cause-effect sequence.

All aspects required by the essay have been sufficiently addressed.

In this essay

Only information relevant to the Mechanism of breathing process and the homeostatic control of carbon dioxide and oxygen.

The mechanism of breathing process is described in the correct sequence and the homeostatic control of respiratory gases are described in the correct logical sequence.

Mechanism of breathing process thoroughly discussed with homeostatic control of respiratory gases.

Marks 1 1 1

Content: 17 Synthesis: 3

TOTAL SECTION C: 20

GRAND TOTAL: 150

GRADE 11 NOVEMBER 2015 LIFE SCIENCES P1...NATIONAL SENIOR CERTIFICATE GRADE 11 NOVEMBER 2015 LIFE...

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