HES1610 Practice Exam

Unit of Study Code: HES1610 Unit Title: Concepts of Biology

MULTIPLE CHOICE QUESTIONS. (30 Marks)

Circle the MOST CORRECT answer. Any corrections must be marked CLEARLY. No marks will be given in case of doubts.Each question is worth 1 mark.

1. Polymers are degraded to their component monomers by a process calledA. dehydration synthesisB. condensationC. hydrogenationD. hydrolysis

2. A transport protein that carries oxygen in red blood cells isA. haemoglobinB. insulinC. actinD. collagen

3. lipids areA. typically hydrophilicB. mainly composed of hydrogen and oxygenC. soluble in non polar solvent and relatively insoluble in water.D. Defined by their structure

4. The term metabolism most precisely describes the cellular process(es) of ----------? A. catalysis of ATPB. breaking down large molecules into smaller ones metabolism C. building large molecules from smaller ones D. B and C

5. Which of the following statements about anabolism is incorrect? A. Anabolism involves synthesis of large molecules from small ones. B. Anabolism manages the storage of excess materials and energy resources. C. Anabolism can lead to tissue building, repair and growth.D. None of these statements is incorrect.

6. Adenosine triphosphate (ATP) functions primarily asA. a precursor of vitamin AB. an "energy carrier" in some enzymic reactionsC. a long-term energy storage moleculeD. a cellular store of phosphate

7. Enzymes are:A. hydrogen carriers in some body reactionsB. catalysts found in all living cellsC. macromolecules containing DNA that “make reactions happen”D. catalysts found in animals and plants but not in bacteria

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8. Enzymes:A. consist mostly of protein, even though some enzymes destroy proteinB. consist mostly of protein in which the sequence of nucleotides is importantC. contain an active site, where the substrate binds during reactionsD. A and C

9. An enzyme catalyzes a reaction by A. supplying the energy to speed up a reaction. B. lowering the energy of activation of a reaction. C. changing the equilibrium of a spontaneous reaction. D. increasing the amount of free energy of a reaction.

10. The induced fit model most correctly describes the way an enzyme and substrate bind to each other because:

A. The substrate changes its shape slightly upon binding to the enzyme for a better fitB. The hand-in-glove model alters the enzyme permanentlyC. The induction of gene expression creates a better fit of the enzyme to substrateD. The enzyme changes its shape slightly upon binding to the substrate for a better fit

11. An increase in the levels of NADH and ATP in cells is likely to occur under which condition(s)?

A. increased activity of catabolic pathways B. decreased activity of anabolic pathways C. inhibition of anabolic pathways D. A and B

12. The reason why humans can metabolise starch but not cellulose is---A. Starch is a smaller polymer than cellulose, therefore easier to break down.B. Starch digestion starts earlier, in the mouth, and gets longer time for completion than

cellulose digestion.C. The chemical bonds in starch can be broken by certain human enzymes, those in

cellulose can’t.D. Human bodies store cellulose as the energy supply and so, cannot metabolise it.

13. The role of bile produced by the liver and stored in the gall bladder is-----A. To digest the proteins in food.B. To emulsify and disperse the fats so they can be digested by appropriate enzymes.C. To digest cellulose.D. To secrete insulin.

14. The two main enzymes ----- and -- digest ------- in our food:A. StarchB. GlycogenC. LipidsD. Proteins

15. Malnutrition refers to-----------A. Inadequate amounts of total calorie (food) intakeB. Inadequate amounts of a specific component of foodC. Inadequate amounts of all vitaminsD. Inadequate amounts of all proteins

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16. The two hormones that regulate blood sugar balance are --------------- and --------------.A. Insulin and glucagonB. Pepsin and trypsinC. Lipase and maltaseD. Trypsin and chymotrypsin

17. The cells of the stomach are themselves not broken down by the acids and enzymes because:A. They are coated with mucousB. They secrete an alkali to neutralise the acidC. The digestive enzymes are secreted in the stomach an inactive form.D. A and C

18. Nicotinamide adenine dinucleotide (NAD) isA. a precursor of coenzyme AB. a precursor of niacinC. a vitamin important for visionD. a carrier molecule for Hydrogen atoms

19. The condition of kwashiorkorA. occurs when the diet is deficient in essential amino acidsB. occurs when the diet is deficient in proteinC. is a consequence of childhood obesityD. occurs when the diet is deficient in protein and carbohydrate.

20. Mitochondria have the general function of A. producing oxygen from the breakdown of food moleculesB. using oxygen and forming lactic acidC. breaking down molecules from food and forming ADPD. breaking down molecules from food and forming ATP

21. Protein is primarily important in the diet asA. a source of saccharides for making proteinB. a source amino acids for making proteinC. a source of building blocks for making DNAD. a source of amino acids for making starch.

22. The condition of marasmusA. occurs when the diet is deficient in essential amino acidsB. occurs when the diet is deficient in proteinC. is a consequence of childhood obesityD. occurs when the diet is deficient in protein and carbohydrate.

23. Type I diabetes mellitusA. occurs when insulin is not made in the pancreasB. occurs when the diet is deficient in essential amino acidsC. occurs when the diet is deficient in proteinD. is a consequence of childhood obesity

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24. A gene represents a section of DNA that:A. Can be double-strandedB. Is made up of all types of base pairs C. Can be transcribed into any type of RNAD. Is able to replicate

28. The ------- and ------- make up the backbone of the DNA helix, while ---- make up its interior:A. Sugars; phosphates; basesB. Adenines; thymines; guaninesC. Bases; phosphates; sugarsD. Phosphates; hydrogen bonds; phosphodiester bonds.

29. The two chains of DNA must run in ---------- direction(s) and must be -------- if they are to bond with each other.

A. the same; uncomplimentaryB. opposite; uncomplimentaryC. parallel; complimentaryD. antiparallel; complementary

SHORT ANSWER QUESTIONS

Short question 1: Fill in the gaps. (Total 10 marks)One mark per question. Fractional mark given less than 0.5 can be given.

A. In meiotic cell division, the homologous chromosomes separate at the ----------------------

stage, while the sister chromatids separate at the ------------------------------ stage.

B. The main types of RNA molecules in the cell are -----------------------------------------.

C. DNA chains are called directional because ------------------------------------------------------- and

antiparallel because ---------------------------------------------------------------------------------------.

D. RNA differs from DNA in three respects: ---------------------------------------,

------------------------------------------------ and -------------------------------------------------.

E. ----------------------- and ---------------------------- are examples of infectious agents which do

not have nucleic acids.

F. The human skin colour is an example of a trait governed by one/ two/ three/ multiple genes, while the left- or right-handedness is an example of a trait governed by one/ two/ three/ multiple genes (circle your choices for each trait).

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G. The properties of water that allow it to climb to the top of plants are: ---------------------------

and -------------------------------------.

H. Using the Table of Genetic Code provided below, translate the following mRNA sequence into an amino acid sequence: CACAAAUACGAG

------------------------------------------------------------------------

I. If the adenine base (A) and the cytosine base (C) shown in bold and underlined in the above sequence are mutated (changed) to a guanine (G) and an adenine (A) respectively, work out what the amino acid sequence would be:

-----------------------------------------------------------------------.

Table of genetic code to be used for Short question 1, parts I, J:

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Short question 2: (Total 10 marks)Address the following problems in genetics. Please consider all possibilities and explain your answers with the help of appropriate gene symbols and Punnett square(s) drawn in the given spaces. No marks will be given if the Punnett square(s) are missing or incorrect.

A. In the fruit fly Drosophila, the gene for eye colour is located on the X-chromosome, white eye colour (w) being recessive to red eye colour (W). The females are XX while males are XY. If a red-eyed female is crossed with a while-eyed male, what will be the eye colour(s) of the progeny of the male and female flies? Consider all possibilities and explain your answer with appropriate gene symbols and Punnett square(s). (3 marks)

B. What will be the blood type (s) of the children born to a couple where the mother has type AB blood and the father has type A blood? Consider all possibilities and explain your answer with appropriate gene symbols and Punnett square(s). (3 marks)

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Eye colour(s) of males:

Eye colour(s) of females:


C: What are the predicted phenotypes of the male and female children from the union of a woman who has an autosomal dominant condition for dwarfism and is heterozygous for it, and a man who is of normal height? Consider all possibilities and explain your answer with appropriate gene symbols and Punnett square(s). (2 marks)

D: In snapdragons, if a pink-flowered plant is crossed with another pink-flowered plant, the F1 generation has red, white and pink flowers. What is this phenomenon is called? Consider all possibilities and explain your answer with appropriate gene symbols and Punnett square(s).

(2 marks)

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Short question 3: (5 marks)With the help of clear and labelled diagrams, illustrate the basic chemical structures of (i) one subunit of DNA (2 marks); and (ii) the DNA double helix (3 marks).

LONG ANSWER QUESTIONS

Long question 1 (10 marks)

You are given a diploid (2n) cell with a chromosome number of 4, i.e., two pairs of homologous chromosomes, one pair being of a shorter chromosomes than the other. With the help of clear, labelled, coloured or pencil-shaded, diagrams, illustrate the events at the division of this cell at (i) all stages of mitosis (8 marks) and (ii) at the prophase of meiosis I only (2 marks). The figures MUST SHOW CLEARLY all relevant detail at the required stages, for the alignment/movement/fate of both pairs of chromosomes and all chromatids. Do not write any description except labels. The figures should be self-explanatory.

Space for answer: on next page.

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Mitosis

Prophase I of meiosis


Long question 2. (25 marks)Write detailed notes on any FIVE of the following. DO NOT write more than five: only the first FIVE will be marked. (5 marks each)

1. Any two distinct types of lipids in cells: their structures, properties and roles/significance. 2. Higher order (secondary and above) structures of proteins, their significance and the types of

chemical bonds that are responsible for forming these structures.3. Regulation of blood glucose levels and the causes and effects of a disease related to this.4. Mendel’s two main laws of inheritance.5. Properties of DNA that allow it to function as the genetic material.6. Comparison of the three major modes of exchange of genetic information in bacteria.7. The unique properties of prions and two examples of the diseases caused by them.

Space for writing answers: on this and the next page

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HES1610 Practice Exam

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