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UNIVERSITY ENTRANCE EXAMINATION 2017

BIOLOGY

Duration : 2 hours

Please read the following instructions carefully.

1. This paper is made up of 60 Multiple-Choice questions and comprises SEVENTEEN

(17) printed pages.

2. Answer all questions and indicate your answers directly in the answer sheet

provided. Marks will not be deducted for wrong answers.

3. Do not take any paper, including the question paper or unused answer sheets, out

of the examination hall.

UEE Biology - Set 3

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1. The primary structure of tuftsin, a short peptide, is shown below.

Which bond, as referred by the numbered arrows, will hydrolysis breaks?

A. 1

B. 2

C. 3

D. 4

2. Which of the following statements is TRUE about enzymes?

A. An enzyme reduces the energy required to start a reaction by partially supplying

additional activation energy.

B. An allosteric inhibitor binds permanently to the active site of an enzyme.

C. A competitive inhibitor binds reversibly to the non-active site of an enzyme.

D. Reaction rates are affected by extreme pH due to the disruption of hydrogen bonding.

3. Which of the following organelles would be relatively more abundant in the muscle cells of an athlete?

A. Nuclei. B. Mitochondria. C. Smooth endoplasmic reticulum. D. Rough endoplasmic reticulum.

1 2 3 4

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4. The diagram represents metabolic pathways in a bacterial cell producing different amino acids by the action of different enzymes. Numbers 1 to 6 represent different amino acids; letters V to Z represent different enzymes. All amino acids are essential for survival.

The original strain of the bacterium required only amino acid 1. A mutant strain of this bacterium could only survive when provided with amino acids 1, 2 and 6 in its culture medium. Which enzymes were missing in the mutant strain?

A. V and W only. B. V and Y only. C. W and Y only. D. V, W and Y only.

5. Sickle cell anemia in humans is caused by a recessive allele. How many copies of this allele will be found in a cell at the end of interphase in a patient with sickle cell anemia?

A. 1 B. 2 C. 4 D. 23 6. The following food tests were carried out separately on a sample and the following

results were obtained.

Food tests Observations

Benedict’s test Brick-red precipitate

Adding of potassium iodide solution Brown

Emulsion test Cloudy

Biuret test Purple

Which of the following is TRUE about the sample? A. It contains fat and protein. B. It contains fat and starch. C. It contains sucrose, starch and protein. D. It contains sucrose, fat and protein.

1 2 4 6 V W Y

3 5

X Z

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7. Some fresh rat liver was homogenized and the suspension was subjected to differential

centrifugation. The procedure is shown below (g represents gravitational force).

Which of the following cellular structures is likely contained in Fraction 4? A. Lysosomes B. Mitochondria. C. Nuclei. D. Ribosomes.

8. The Table below shows the percentages of nitrogenous bases in four samples of nucleic

acids. Which base is adenine?

Sample Nitrogenous Bases (%)

A B C D Uracil

1

2

3

26 23.9 24 26.1 0

28.2 22 21.8 28 0

25 25 0 25 25

Homogenate

Centrifuge at 800 g for 10 minutes

Fraction 1

Supernatant

Centrifuge at 2000 g for 15 minutes

Supernatant

Centrifuge at 25000 g for 10 minutes

Supernatant

Fraction 2

Centrifuge at 105000 g for 60 minutes

Fraction 3

Fraction 4

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9. Part of a metabolic pathway involving synthesis of threonine and lysine via aspartate and several intermediates is shown below.

Which of the following changes in enzyme activity will result in the greatest increase in lysine yield? A. Decrease enzyme 1 activity. B. Increase enzyme 2 activity. C. Increase enzyme 3 activity. D. Decrease enzyme 4 activity.

10. Which of the following statements regarding a human mature sperm cell and mature egg cell is/are TRUE?

I. They will have the same number of chromosomes. II. They will have the same number of genes. III. They will have the same DNA sequences. A. I only. B. I and II only. C. I and III only. D. I, II and III.

11. Which of the following statements about DNA replication in the cell is FALSE? A. DNA polymerase joins new nucleotides to the 3’ end of the growing strand. B. The lagging strand and the leading strand are simultaneously synthesized during DNA

replication. C. Phosphodiester bonds are not broken and formed during DNA replication. D. RNA primer is required to initiate DNA replication.

aspartate

aspartyl phosphate

aspartic semialdehyde

homoserine

threonine

lysine

enzyme 1

enzyme 2

enzyme 3

enzyme 4

inhibition

inhibition

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12. Which of the following enzyme activities is/are NOT found in the reverse transcriptase of Human Immunodeficiency Virus (HIV)?

I. DNA dependent RNA polymerase activity. II. DNA dependent DNA polymerase activity. III. RNA dependent RNA polymerase activity.

A. I only. B. II only. C. I and III only. D. II and III only.

13. Which of the following statements is/are FALSE regarding the control of lac operon in E. coli?

I. If a mutation occurs in the lac repressor protein and prevents it from binding to allolactose,

E. coli will not be able to grow well in a medium with only lactose. II. If a mutation occurs in the lac repressor protein and prevents it from binding to the lac operator, E. coli will not be able to grow well in a medium with only lactose. III. If a mutation prevents RNA polymerase from binding to the promoter the lac operon, E. coli will not be able to grow well in a medium with only glucose. A. I only. B. I and III only. C. II and III only. D. I, II and III.

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14. The Table below show the genetic codon for several amino acids.

Genetic Codon Amino acids

5’-CGU-3’ Arginine

5’-UGC-3’ Cysteine

5’-CGA-3’ Arginine

5’-ACG-3’ Threonine

5’-GCA-3’ Alanine

5’-UCG-3’ Serine

An anticodon of a t-RNA was mutated from 5’-CGU-3’ to 5’-CGA-3’. Which of the following statements is TRUE as a result of this mutation? A. Alanine could be replaced by Arginine during translation. B. Serine could be replaced by Threonine during translation. C. Arginine could be replaced by Cysteine during translation. D. Threonine could be replaced by Serine during translation.

15. Which of the following statements is/are FALSE regarding viruses? I. A virus with a lytic cycle must have a gene that encodes integrase. II. The influenza virus uses viral RNA as a template for viral DNA synthesis. III. An E coli cell carrying a lambda prophage is immune to infection by a second lambda virus because the proteins from the prophage lysogenic genetic program prevent replication of the second virus. A. I only. B. I and II only. C. I and III only. D. II and III only. 16. The following are bonds that can be formed and broken during cellular processes: 1. Formation of hydrogen bonds. 2. Breaking of hydrogen bonds. 3. Formation of peptide bonds 4. Breaking of peptide bonds. Which of the above occur when during translation in a bacterial cell? A. 1 and 3 only. B. 3 and 4 only. C. 1, 2 and 3 only. D. 1, 2, 3 and 4.

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17. A single stranded DNA is shown below:

5'-CCGGTACCCCGTACGCTACGGGACTAGGCCGGAAGGTCCTTGGCG-3'

This single stranded DNA is mixed with DNA polymerase, deoxynucleoside triphosphates, appropriate buffer and a primer. Which of the following sequences if added as the single primer in the mixture is unlikely to be extended by the DNA polymerase under optimal condition?

A. 5'-CGCCAAGGAC-3' B. 5'-GGCCTAGTCC-3' C. 5'-GCGTACGGGG-3' D. 5'-GGGGTACCGG-3'

18. The diagram shows the structure of an animal cell.

Which labelled organelle(s) would you find translation to occur? A. 1 and 4 only. B. 2 and 3 only. C. 3 and 4 only. D. 4 only.

19. A culture of bacterial cells with DNA that comprises only heavy nitrogen, 15N, in generation 1 were subsequently grown in a medium containing only normal nitrogen, 14N, for another three generations (i.e. generation 2, 3 and 4). What is the percentage of the cells with DNA molecules containing 15N at generation 4?

A. 12.5%.

B. 25%.

C. 75%.

D. 87.5%.

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20. Assume that amino acid residues have an average molecular weight of 110. How many nucleotides are needed to code for a polypeptide chain with a molecular weight of 12320?

A. 112 B. 224 C. 336 D. 672

21. Which of the following statements is TRUE?

A. Natural selection requires a mass extinction by meteorite impact, reproducing units and

fitness differences in order to occur. B. Natural selection requires the presence of natural disasters, heritable variability and

reproducing units in order to occur. C. Natural selection requires fitness differences, heritable variability and reproducing units

in order to occur. D. Natural selection requires climate change, reproducing units and heritable variability to

be present in order to occur.

22. The following are examples of evolution via natural selection except for: A. The increase in resistance within the predatory garter snake to the toxin emitted by

newt prey. B. Countershading (dark dorsal and white ventral body) of penguins, great white sharks

and killer whales to better camouflage to the marine environment. C. The variability of the third codon position of a protein-coding gene in a population of

dolphins which have no phenotypic differences. D. The increasing complexity in the mating call of a song bird to demonstrate the stamina

of the male bird.

23. A small population of shrews colonised an island far from their original home range. Due

to the lack of insects which were their typical diet, the shrews switched to feeding mainly on flower nectar which was an abundant food source. Over time, the shrews spread to other nearby islands and specialised on different types of plant nectar. This is an example of _____.

A. adaptive radiation B. analogous evolution C. convergent evolution D. genetic drift

24. Which of the following are examples of convergent evolution? A. The eye of a crocodile and the eye of a snake. B. The wing of a bird and the wing of the insect. C. The tail of the squirrel and the tail of the chimpanzee. D. The root of a fern and the root of a dicotyledonous tree.

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25. The southern beech trees, land plants in the genus Nothofagus, live primarily in South America, Australia and New Zealand. Fossils of this plant have also been found in Antarctica. What could account for this geographically disjointed distribution?

A. South America, Australia and New Zealand used to be connected via Antarctica. B. The plants can now actively move between the land masses over the oceans. C. Southern beech trees have independently gone extinct in other land masses. D. Southern beech trees in each continent evolved independently from other unrelated

plants.

26. When a large number of individuals from a mosquito species originally from a mainland population colonise a small uninhabited offshore island, the risk of extinction on the island is _____.

A. high because there may be insufficient food resources B. high because there are no predators C. low because mutation rates will increase D. low because there are guaranteed food resources available in the new environment

27. Which of the following options is the most likely consequence of the neutral theory of molecular evolution?

A. Beneficial mutations spread quickly through the population. B. Coding parts of the genome are reduced in proportion. C. Mutation rates are negatively correlated with the pH of the environment. D. Variation within and between species results from mutations that do not affect an

organism's ability to survive and reproduce.

28. Tay–Sachs disease is a rare genetic disorder caused by a recessive allele. Patients with the homozygous genotype exhibit progressive deterioration of nerve cells and usually die by the age of four. People with the heterozygous condition do not exhibit symptoms of the disease but appear to be protected to some extent against tuberculosis. Which of the following could account for the persistence of the recessive allele?

A. Natural selection favouring homozygotes. B. Natural selection favouring heterozygotes. C. Genetic drift favouring heterozygotes. D. Incomplete penetrance favouring homozygotes.

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29. The following scheme describes the DNA transcription process to produce functional messenger RNA (mRNA) in eukaryotes.

DNA template → DNA uncoiled to expose promoter region → pre-mRNA → spliced mRNA → polyadenylated mRNA → functional mRNA

Which of the following options is involved in the synthesis of pre-mRNA from the uncoiled DNA?

A. DNA polymerase B. RNA polymerase C. p53 D. spliceosome

30. An unknown unicellular organism is found to have a single point of origin for DNA

replication during the reproductive phase. Which of the following options is this

organism most likely to be?

A. A fungus with a simple life cycle in the soil. B. A missing link between fungi and animals. C. An asexual prokaryotic bacteria. D. A sexual eukaryotic unicellular organism.

31. A gene region was sequenced from many closely-related species of beetles and the nucleotide sequences were compared. It was found that the sequences were almost identical among the different species in alternate sections of the gene. Which of the following statements best explains this pattern?

A. The alternate sections are introns that are not under strong selection pressure and thus

they do not undergo many mutations. B. The alternate sections are exons that code for parts of a functional protein and there is

selection pressure to keep the nucleotide sequence conserved. C. The alternate sections are anticodons and therefore do not undergo mutations. D. The gene is not expressed and there is convergent genetic evolution among the different

species.

32. The operon system enables _____. A. compartmentalisation of eukaryotic cellular processes to allow for clear division of

labour B. rapid response by eukaryotic cells by the recombination of gametes C. prokaryotic cells to react to external stimuli rapidly by activating several gene sequences

using a single promoter region D. incorporation of plasmids that may contain beneficial traits for rapid response to

environmental stressors

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33. Which of the following phenomena occurs during the anaphase stage of mitosis?

A. Chromatids double in size. B. Cytokinesis is complete. C. Each centromere splits into two. D. Telomeres double in size.

34. Cancer cells have unregulated growth and attained immortality by not experiencing the usual DNA degradation by normal somatic cells. In such a scenario, you would expect the telomerase activity in such cancerous cells to be ____.

A. activated and functional B. inactivated and non-functional C. activated but silenced D. inactivated and suppressed

35. Mutations in the Myc gene lead to an overactive cell proliferation pathway. Which of the following best describes this type of mutation?

A. Loss-of-function mutation of an oncogene. B. Loss-of-function of an operon gene. C. Gain-of-function mutation of a tumour suppressor gene. D. Gain-of-function mutation of an oncogene.

36. Golden rice is a variety of Asian rice produced through genetic engineering to biosynthesise one or more compounds in the edible parts of rice. The desired effects of this product are _____.

I. higher yield due to reduced pest damage to the edible parts II. ability to tolerate high summer temperatures III. the compound(s) produced is beta-carotene IV. the compound(s) produced is unsafe for pests V. the compound(s) produced is safe for human consumption

B. I, II and III only C. II, III, and IV only D. III and V only E. IV and V only

37. Which of the following statements is a valid concern regarding genetically modified

crops?

A. Genetically modified crops are often not grown in suitable environments. B. Genetically modified crops are unnatural as they have been produced by artificial

methods. C. Crops producing anti-pest toxins may rapidly lose its effectiveness once pests evolve

resistance. D. Crops producing anti-pest toxins often produce lower yields that are not profitable.

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38. Rank the terms below in descending order, from the stem cell type that can differentiate into all cell types (first) to the more limited (last).

A. Puripotent, Totipotent, Pluripotent B. Pluripotent, Multipotent, Totipotent C. Totipotent, Multipotent, Pluripotent D. Totipotent, Pluripotent, Multipotent

39. The aim of current human gene therapy techniques is to _____. A. silence a defective gene by introducing a complementary DNA strand to prevent

translation, thereby eliminating the disease B. use epigenetic silencing to prevent the transcription of a defective, thereby eliminating a

disease C. replace a defective gene with an introduced functional copy to produce functional

proteins, thereby eliminating a disease D. introduce transposable elements to target and remove defective genes, thereby

eliminating the disease

40. Which of the following statements regarding gene therapy as a cure for genetic disorders is FALSE?

A. Somatic gene therapy does not lead to a permanent cure because somatic cells that

have the functioning gene inserted may eventually be replaced. B. Germ line gene therapy is preferred in terms of safety over somatic gene therapy

because somatic cell transformation is carried on to the next generation. C. The introduced gene to be incorporated into the patient's chromosome must be

inserted at a specific locus to be effective. D. Gene therapy does not result in all cells in the body acquiring the therapeutic gene in

the current generation.

41. The parents of a family have A and B blood groups, what are the possible blood groups of their children?

A. A and B only B. A, B and AB only C. A, B and O only D. A, B, O and AB

42. Allele M is located at the human X chromosome. A disease is caused by the presence of two copies of the allele M (assuming there is no duplication event of the gene). What is the most likely mode of genetic disorder for the disease?

A. Autosomal, recessive B. Autosomal, dominant C. Sex-linked, recessive D. Sex-linked, dominant

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43. A kind of inherited disease is known to be a sex-linked dominant condition. A family has a son who is diagnosed with the disease. Which of the following statements is FALSE?

A. The father may not have this disease. B. The mother may not have this disease. C. The second son of the family may not have this disease. D. The daughter of the family may not have this disease.

44. Haemophilia is known to be an X-linked recessive disease. A family has a daughter with haemophilia and a normal son. What are the phenotypes of the parents?

Father Mother

A. Carrier Normal B. Haemophilia Carrier C. Haemophilia Haemophilia D. Normal Carrier

45. A cross between a red-flowered tall plant with a white-flowered dwarf plant produced only

red-flowered tall plants. The alleles for the phenotypes are designated as: R: red flower r: white flower T: tall t: dwarf What are the genotypes of the parent plants? A. RrTt x Rrtt B. RrTt x RRtt C. RrTT x Rrtt D. RRTT x rrtt

46. Which of the following statements about variations in phenotypes is TRUE? A. Continuous variation is caused by a single gene. B. Continuous variation is affected by the environment. C. Discontinuous variation is caused by many genes. D. Discontinuous variation can never be affected by the environment.

47. Which of the following statements is FALSE? A. Linked genes are genes that are found on the same chromosome. B. ABO blood group system is a typical example of multiple alleles. C. Epistasis is a term to describe the influence of the environment on the expression of a

gene. D. In a monohybrid cross experiment, if both parents are heterozygous for a Mendelian

trait, then their F1 offspring will show a dominant to recessive phenotypic ratio of 3:1.

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48. Which of the following statements regarding photosynthesis are TRUE?

I. Light joins carbon dioxide to an acceptor compound which is then reduced by hydrogen obtained from water.

II. Photoactivation is the initial stage of the light-dependent reaction. III. In non-cyclic photophosphorylation, electrons are transferred from Photosystem I to

Photosystem II. IV. The Calvin cycle is light independent.

A. I and II only B. I, II and IV only C. II and IV only D. II, III and IV only

49. Which of the following statements is FALSE?

A. Insulin is secreted in response to high blood sugar concentrations. B. Insulin is produced by the pancreas. C. Insulin is synthesized as proinsulin, and converted to insulin before secretion into the

blood stream. D. Insulin suppresses glycogenesis.

50. Which of the following statement(s) regarding G-proteins is/are TRUE? I. G-proteins are activated by extracellular signalling molecules. II. G-proteins can convert GTP to GDP. III. G-protein signalling results in multiple cellular responses.

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

51. Which of the following statements is FALSE?

A. There are three types of neurons. B. The axon transmits a signal away from the cell body. C. During neural signal transmission across a synapse, there is an influx of Ca2+ into the axon. D. During neural signal transmission across a synapse, there is an influx of Na+ into the axon.

52. Which of the following processes is required for food-derived glucose to enter the epithelial cells of the gut?

A. Osmosis B. Facilitated diffusion C. Active transport D. endocytosis

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53. In the Kreb’s cycle, which step produces reduced FAD (i.e. FADH2)?

A. Citric acid isocitric acid

B. Succinic acid fumaric acid

C. Malic acid oxaloacetic acid

D. Fumaric acid malic acid

54. Which is the correct sequence when the following enzymes are used to genetically engineer bacteria to produce human insulin?

A. ligase reverse transcriptase restriction endonuclease

B. reverse transcriptase restriction endonuclease ligase

C. restriction endonuclease ligase reverse transcriptase

D. reverse transcriptase ligase restriction endonuclease

55. A bacterial clone hosts a recombinant DNA plasmid with the DNA fragment carrying Gene A inserted into the lacZ gene region also contained in the plasmid. The bacteria are plated on medium containing the antibiotic tetracycline and the compound X-gal. What would you expect to observe if the plasmid only contains an ampicillin-resistance gene but not a tetracycline-resistance gene (the bacterial genome does not contain any antibiotic-resistance gene)?

A. Only white colonies will be observed. B. Both blue and white colonies will be observed. C. Only blue colonies will be observed. D. No colonies will be observed.

56. Which of the following statement(s) is/are TRUE regarding PCR?

I. The denatured DNA strands tend to anneal with primers rather than with their complimentary strands because the primers are shorter and can move faster in solution.

II. A single-stranded DNA can be used as the template for PCR reaction. III. In theory, it needs at least 7 PCR cycles to amplify more than 100 copies from one

double-stranded DNA molecule.

A. I and II only B. I and III only C. II and III only D. I, II and III

57. Which of the following statements is TRUE about DNA gel electrophoresis?

A. All DNA fragments migrate to the positive end of the electrical field. B. DNA fragments are separated by different charges. C. Longer DNA fragments migrate faster than shorter fragments. D. A and C only.

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58. Which of the following statements CORRECTLY describe(s) the events in a PCR reaction?

A. The order of the reaction cycle is strand denaturation, product extension, and primer

annealing. B. It follows an exponential increase in the number of molecules generated. C. It works best when the primer and target sequences are in their highest degree of

complementarity. D. B and C only.

59. Which of the following options are NOT relevant to RFLP?

I. DNA polymerase II. RNA polymerase III. Restriction enzymes IV. Southern blot

A. I and II only B. II and III only C. I, II and IV only D. II, III and IV only

60. Which of the following statements about the Human Genome Project (HGP) are FALSE?

I. HGP aimed to map and sequence the genetic makeup of individual human being. II. HGP allowed patenting of genes to obtain further funding for sequencing research. III. HGP emphasized the use of bioinformatics and biocomputing to mine genome

databases. IV. HGP aimed to obtain a genetic linkage map of the human genome.

A. I and II only B. II and III only C. III and IV only D. I, II and IV only

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