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UNIVERSITY ENTRANCE EXAMINATION
BIOLOGY
Duration
: 2 hours
Please read the following instructions carefully.
1. This paper is made up of 60 Multiple-Choice questions and comprises sixteen (16)
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.
1 1. The diagram shows the structure of animal cell.
Which labelled structure(s) would be relatively more abundant in gonad cells that synthesizes male and female hormones? A.
B.
C.
D.
1 only.
2 only.
2 and 3 only.
1 and 4 only.
2. Which of the following statements regarding the type of nucleic acids contain in the cellular
structures is TRUE?
A.
B.
C.
D.
Chloroplasts contain DNA but not RNA.
Mitochondria contain DNA but not RNA.
Ribosomes contain RNA but not DNA.
Endoplasmic reticula contain DNA and RNA.
3. Which of the following statement is TRUE?
A. A glycosidic bond is formed between the carbon of one sugar and the carbon of another
sugar.
B. The phosphodiester bond is formed between the phosphate group of a sugar and the
ketone group of a nucleobase.
C. A triglyceride is formed by a reaction between glycerol and fatty acids.
D. A peptide bond is formed between an amino group of one amino acid and the aldehyde
group of another amino acid.
2 4. The diagram is an outline of the procedure for separation of cell components from a liver
homogenate in 0.25 M sucrose at 0 ◦C.
Homogenate Centrifuge at 600 g for 10 min
Precipitate X Supernatant
Centrifuge at 10,000 g for 10 min
Precipitate Y Supernatant Centrifuge at 150,000 g for 10 Precipitate Z Supernatant Which of the following statement is TRUE? A.
B.
C.
D.
Precipitate X likely contains cell walls
Precipitate X likely contains ribosomes.
Precipitate Y likely contains mitochondria.
Precipitate Z likely r contains nuclei.
5. Food tests were carried out on four solutions and the following results were obtained.
Which solution contains only maltose and starch?
Adding of potassium iodide solution Biuret test blue Acid hydrolysis followed by neutralization and Benedict’s test brick red precipitate blue‐black purple B brick red precipitate brick red precipitate brown purple C blue brick red precipitate
blue‐black blue
D brick red precipitate
brick red precipitate
blue‐black blue
Solution Benedict’s test A 3 6. Which of the following statements about enzymes is TRUE? A. An enzyme reduces the energy required to start a reaction by partially supplying additional activation energy. B. A non‐competitive inhibitor usually binds permanently to the active site of an enzyme. C. A competitive inhibitor usually is structurally similar to the substrate of an enzyme. D. Reaction rates are affected by extreme pH due to reduced collision rates of active sites. 7. Which of the following bonds hold the secondary structure of a protein? A. Disulphide bond. B. Hydrogen bond. C. Peptide bond. D. Phosphodiester bond. 8. 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 (generation 2, 3 and 4). What is the percentage of the cells with DNA molecules containing 15N at generation 4? A. 6.25%. B. 12.5%. C. 25%. D. 50%. 9. The diagram shows a certain cell undergoing nuclear division. Which of the following statements could be represented by the diagram? A. Four pairs of homologous chromosomes undergoing Anaphase of mitosis. B. Four non‐homologous chromosomes undergoing Anaphase II of meiosis. C. Two pairs of homologous chromosomes undergoing Metaphase of mitosis. D. Two pairs of homologous chromosomes undergoing Anaphase I of meiosis. 4 10. The enzyme amylase catalyzes the conversion of starch to maltose. It has been determined
that 10 mL of 1 % amylase can convert 5 mL of starch to X amount of maltose in 10 minutes
in excess of substrate. Which of the following statement is FALSE?
A. If the concentration of enzyme is increased in the above reaction mixture, X amount of
maltose will be produced in less than 10 minutes.
B. If the volume of starch is increased in the above reaction mixture, more than X amount
of maltose will be produced in 10 minutes.
C. If a non‐competitive inhibitor is added to the above reaction mixture, X amount of
maltose will be produced in more than 10 minutes.
D. If the concentration of the enzyme is increased in the above reaction mixture, more than
X amount of maltose will be produced in 10 minutes.
11. Which of the following statements is/are TRUE?
I. If the genetic material of a virus has 21% adenine, 21% guanine, 29% uracil, 29% cytosine,
it is likely a single‐stranded RNA virus.
II. If a double‐stranded DNA contains 32% cytosine, then the proportion of adenine in the
double‐stranded DNA is 18%.
III. If an mRNA has 28% adenine and it is transcribed from a bacterial gene, then the
proportion of adenine and thymine in the bacterial gene is 56%.
A.
B.
C.
D.
I only.
I and II only.
II and III only.
I, II and III.
12. The table below shows the genetic code for several amino acids.
Genetic Code 5’‐CGU‐3’ 5’‐UGC‐3’ 5’‐CGA‐3’ 5’‐ACG‐3’ 5’‐GCA‐3’ 5’‐UCG‐3’ Amino acids Arginine Cysteine Arginine
Threonine Alanine 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.
B.
C.
D.
Alanine could be replaced by Arginine during translation.
Serine could be replaced by Threonine during translation.
Arginine could be replaced by Cysteine during translation.
Threonine could be replaced by Serine during translation.
5 13. Which of the following statements regarding virus is/are FALSE?
I. A virus with a lysogenic 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 lytic genetic program prevent replication
of the second virus.
A.
B.
C.
D.
I only.
I and II only.
I and III only.
II and III only.
14. Which of the following statements about DNA replication is FALSE?
A. DNA polymerase joins new nucleotides to the 5’ end of the growing strand.
B. The lagging strand and the leading strand are simultaneously synthesized during DNA
replication.
C. RNA primer is required to initiate DNA replication.
D. Hydrogen bonds are broken and formed during DNA replication.
15. Gene X encodes a polypeptide containing twelve amino acids A‐B‐C‐D‐E‐F‐G‐H‐I‐J‐K‐L, (each
letter represents one amino acid). Amino acid ‘A’ is at the N‐terminus and amino acid ‘L’ is at
the C‐terminus of this polypeptide. A mutation occurs on gene X such that nucleotide
guanine at the 15th nucleotide counting from the last nucleotide of the stop codon on the
mRNA is substituted by thymine. This changes one amino acid to ‘J’. Which of the following
would be the mutant polypeptide?
A.
B.
C.
D.
A‐B‐C‐D‐E‐J‐G‐H‐I‐J‐K‐L
A‐B‐C‐D‐E‐F‐J‐H‐I‐J‐K‐L
A‐B‐C‐D‐E‐F‐G‐J‐I‐J‐K‐L
A‐B‐C‐D‐E‐F‐G‐H‐J‐J‐K‐L
16. Which of the following statements regarding two normal mature sperm cells from the same
individual is/are FALSE?
I. They will have the same DNA sequences.
II. They will have the same number of genes.
III. They will have the same number of chromosomes.
A.
B.
C.
D.
I only.
II only.
I and II only.
II and III only.
6 17. Which of the following enzyme activities is/are 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 DNA polymerase activity.
A.
B.
C.
D.
I only.
II only.
I and II only.
II and III only.
18. Which of the following statements regarding the control of lac operon in E. coli is/are TRUE?
I. If a mutation occurs in the lac repressor and prevent it from binding to allolactose, E. coli
will be able to grow well in a medium with only lactose.
II. If a mutation occurs in the lac repressor protein and prevent 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 of the lac operon,
E. coli will be able to grow well in a medium with only glucose.
A.
B.
C.
D.
I only.
I and III only.
II and III only.
I, II and III.
19. Which of the following statements about translation is TRUE?
A.
B.
C.
D.
Hydrogen bonds are broken and formed during translation.
The mRNA is translated from 3’ to 5’ direction.
Peptide bonds are broken and formed during translation.
Amino acids are added onto the amino terminus of the growing polypeptide chain.
20. Which of the following statements is/are TRUE?
I. Mutation that occurs in an early developing embryo may be passed down to the next
generation.
II. Sickle cell anaemia is caused by gene mutation.
III. Down’s syndrome is caused by gene mutation.
A.
B.
C.
D.
I only.
II only.
I and II only.
II and III only.
7 21. The following is the taxonomic classification of the domestic cat.
Animalia
Chordata Mammalia Carnivora Felidae Felis Felis catus Which phylum does the domestic cat belong to? A.
B.
C.
D.
Chordata
Mammalia
Carnivora
Felidae
22. Which one of the following community interactions is considered mutualism?
A.
B.
C.
D.
A frog hunting feeding on an insect.
Microbes not harming their hosts so they can feed from it.
Mating between a male and female tiger.
Monarch caterpillar feeding on milkweed.
23. Which of the following statements about natural selection is FALSE?
A.
B.
C.
D.
It can improve the adaptation of species.
More offspring are produced than can possibly survive to sexual maturity.
Increased differences between populations can lead to speciation.
Characteristics acquired during an organism's lifetime are always passed on to its
offspring.
24. Which of the following terms describes similar characteristics in different species due to
their descent from a common evolutionary ancestor?
A.
B.
C.
D.
Homology
Phylogeny
Taxonomy
Phenology
8 25. Which of the following statements is the most likely consequence of the neutral theory of molecular evolution? A. Genetic mutations are suspended. B. Genetic variation occurs due to random drift of alleles that are not affected by natural selection. C. Deleterious mutations spread quickly through the population. D. Mutation rates are negatively correlated with temperature. 26. Marsupials are a group of closely‐related terrestrial mammals living primarily in Australia and South America since about 50 millions years ago. What could account for this geographically disjointed distribution? A.
B.
C.
D.
Marsupials have independently gone extinct in other land masses. South America and Australia used to be connected via Antarctica. Humans have been actively transporting marsupials between the two continents. Marsupials in each continent originated independently from other unrelated mammals. 27. Common among Europeans, cystic fibrosis is a genetic disorder caused by a recessive allele. A person with the homozygous genotype has a reduced life expectancy and is sterile. However, people possessing only one allele for cystic fibrosis, will not experience the ill effects of the disease, and yet be resistant to diseases involving loss of body fluid (e.g. cholera). What could account for the high incidence of the recessive allele in the European population? A.
B.
C.
D.
Epigenetic changes favouring heterozygotes. Underdominance of the recessive allele. High mutation rate of the recessive allele. Natural selection favouring heterozygotes. 28. Which of the following options is NOT a control of gene expression at the post‐translational level? A.
B.
C.
D.
Binding of ubiquitin to the polypeptide. Proteolytic cleavage of the polypeptide to form functional protein. Glycosylation of the polypeptide for the production of glycoprotein. Binding of inhibitor proteins that block the translocation of the ribosome. 9 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 → func onal mRNA Which of the following options is NOT involved in the catalysis of the above process? A.
B.
C.
D.
Spliceosome RNA polymerase DNA polymerase DNA topoisomerase 30. When comparing two naturally fluorescent jellyfish species, one is much brighter than the other under ultraviolet light. When the genetic mechanism of the fluorescence was determined, the difference in brightness was attributed to the amount of green fluorescent proteins (GFPs) produced by the two different jellyfish species. Which of the following is the most likely explanation of the difference? A. There is an enhancer region upstream of the GFP gene in one species but not the other. B. There is a transcription start site upstream of the GFP gene in one species but not the other. C. There is a transposable element upstream of the GFP gene in one species but not the other. D. The GFP gene is not expressed in both species. 31. Which of the following phenomena can potentially lead to cancer formation? I.
II.
III.
IV.
V.
A gain‐of‐function mutation in an oncogene. A loss‐of‐function mutation in a tumour suppressor gene. Infection by the Middle East respiratory syndrome coronavirus. Inactivation of cell division. Inactivation of a programmed cell death gene. B.
C.
D.
E.
I and II only I and IV only I, II and V only II, IV and V only 32. Which of the following descriptions is a possible mechanism of an anti‐cancer drug? A. The drug blocks all cells from expressing telomerase. B. The drug raises the chance of infection by cancer‐causing viruses. C. The drug competes for binding to and inactivation of a signalling molecule that promotes cell division. D. The drug binds to an enhancer region of a proto‐oncogene that increases its rate of transcription. 10 33. Cancers can occur at any age, but the risk of developing cancer increases with age. Which of
the following statements is the most likely explanation for this pattern?
A.
B.
C.
D.
Older individuals are more likely to have more proto‐oncogenes.
Older individuals are more likely to have more tumour suppressor genes.
Older individuals are more likely to have more cell division genes.
Older individuals are more likely to have accumulated random mutations that increase
cancer risk during their lifetime.
34. Why do prokaryotic cells lack telomeres?
A.
B.
C.
D.
They are resistant to viral transposable elements.
They have a circular DNA.
Their genome is too small to insert telomeres.
Plasmids have replaced the role of telomeres.
35. Which of the following descriptions is NOT a feature of stem cells in humans?
A.
B.
C.
D.
They are capable of dividing indefinitely.
They can differentiate into specialised cell types.
They are found only in adolescent children.
They can become cancerous.
36. Which of the following cells does gene therapy need to target in order for the treatment of a
genetic disease to be effective beyond the patient to his/her offspring?
A.
B.
C.
D.
Autosomal cells
Germline cells
Neuronal cells
Somatic cells
37. Which of the following statements is a risk that prevents gene therapy from becoming an
effective treatment for genetic disease?
A. The introduced gene may increase the mutation rate of the patient's genome.
B. The introduced gene may mutate spontaneously prior to being incorporated into the
patient.
C. The gene may be inserted into the wrong location, resulting in the mutation of proto‐
oncogenes and causing cancer.
D. There is no known method to transfer DNA into the nucleus.
11 38. A couple decided to have their newborn child's umbilical cord blood stem cells stored away for future use. The child grew up and developed kidney damage. When the family requested for the use of the stored stem cells to help repair the kidney, the doctor said that it was not possible. Which of the following is the most likely explanation? A. The cord blood stem cells are pluripotent and thus can differentiate only into limited cell types not including the kidney. B. The cord blood stem cells are multipotent and thus can differentiate only into limited cell types not including the kidney. C. The kidney contains many different types of stem cells which are only available at the embryonic cell stage. D. The kidney does not contain any stem cells and thus can only be grown at the embryonic stage. 39. Golden rice is a variety of Asian rice produced through genetic engineering to biosynthesise _____ in the edible parts of rice. A.
B.
C.
D.
ascorbic acid beta‐carotene Vitamin A Vitamin B12 40. For vegetative propagation of plants, which of the following statements is NOT an advantage of tissue culture over more traditional methods such as cuttings or grafting? A.
B.
C.
D.
It is the only viable method of regenerating genetically modified plants. A larger number of plants can be mass produced in less space. Tissue cultures are more easily transported from place to place. It is a very inexpensive method. 41. Which of the following options is/are NOT a form of gene mutation? I. Replication II. Inversion III. Duplication IV. Division A. I only B. I and II only C. III and IV only D. I and IV only 12 42. Allele Z is located at the human X chromosome. A disease is caused by the presence of two copies of the allele Z (assuming there is no duplication event of the gene). What is the most likely mode of genetic inheritance for the disease? A. Autosomal, recessive B. Autosomal, dominant C. Sex‐linked, recessive D. Sex‐linked, dominant 43. A kind of inherited disease is known to be a sex‐linked recessive condition. A family has a daughter who is diagnosed with the disease. Which of the following statements is FALSE? A. The father must have this disease. B. The mother may not have this disease. C. The second daughter of the family must have this disease. D. The son of the family may not have this disease. 44. Which of the following statements is/are FALSE about mutation? A. Deletion of one nucleotide is likely to have a more profound effect than the deletion of three nucleotides. B. A nonsense mutation produces a completely incorrect sequence of amino acids from the point of mutation to the end of the protein. C. Mutation on the first base of a codon is likely to have a more profound effect than a mutation on the third base of the same codon. D. B and C only. 45. Which of the following mutations CANNOT be caused by insertion or deletion of a single nucleotide? A. Frameshift B. Nonsense mutation C. Silent mutation D. B and C only 46. Which of the following statements about variations in phenotypes is TRUE? A. Continuous variation is caused by many genes. B. Continuous variation is not affected by the environment. C. Discontinuous variation is always caused by one gene. D. Discontinuous variation can never be affected by the environment. 13 47. Which of the following statements is FALSE? A. Linked genes are genes that are found on the same chromosome. B. ABO blood group 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. 48. Which of the following processes does NOT produce ATP? A. Oxidative phosphorylation B. Glycolysis C. Kreb’s cycle D. Calvin cycle 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 sequences is correct in cell signaling? A. Cyclic AMP  G‐protein coupled receptor  Protein Kinase A  hormones B. Hormones  Protein Kinase A  cyclic AMP  G‐protein coupled receptor C. Protein Kinase A  hormones  G‐protein coupled receptor  cyclic AMP D. Hormones  G‐protein coupled receptor  cyclic AMP  Protein Kinase A 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 phenomena are involved in the Calvin cycle? A. Hydrolysis of ATP and the reduction of NADP+. B. Synthesis of ATP and the reduction of NADP+. C. Synthesis of ATP and the oxidation of NADPH. D. Hydrolysis of ATP and the oxidation of NADPH. 14 53. In the Kreb’s cycle, which step produces reduced FAD (i.e. FADH2)?
A.
B.
C.
D.
Citric acid  isocitric acid
Succinic acid  fumaric acid
Malic acid  oxaloacetic acid
Fumaric acid  malic acid
54. Which of the following enzymes is necessary for making a recombinant plasmid in the test
tube?
A.
B.
C.
D.
DNA polymerase
Reverse transcriptase
Helicase
Restriction endoneucleases
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.
B.
C.
D.
Only white colonies will be observed.
Both blue and white colonies will be observed.
Only blue colonies will be observed.
No colonies will be observed.
56. In theory, what is the minimum number of PCR cycles required in order to amplify more
than 200 copies from one double‐stranded DNA molecule at the beginning?
A.
B.
C.
D.
5 cycles
6 cycles
7 cycles
8 cycles
57. Which of the following statements is/are TRUE about DNA gel electrophoresis?
A.
B.
C.
D.
All DNA fragments migrate to the positive end of the electrical field.
DNA fragments are separated by different charges.
Longer DNA fragments migrate faster than shorter fragments.
A and C only.
15 58. Which of the following statements CORRECTLY describe(s) the events in a PCR reaction?
A.
B.
C.
D.
The order of the reaction cycle is strand denaturation, product extension, and primer
annealing.
It follows an exponential increase in the number of molecules generated.
It works best when the primer and target sequences are in their highest degree of
complementarity.
B and C only.
59. Which of the following cases would NOT be possible to resolve using RFLP?
A.
B.
C.
D.
Parental identification where all individuals including possible parents and children are
present.
Identifying individuals with genetic diseases.
A crime scene where some skin cells were found under the nails of the victim and may
belong to a suspect.
B and C only.
60. Which statement is FALSE about the spirit and programs of the Human Genome Project
(HGP)?
A.
B.
C.
D.
Educate the public on social, ethical, and legal issues concerning the implications of the
HGP.
Facilitate genetic testing for improved diagnosis of diseases.
Emphasize the use of bioinformatics and biocomputing to mine genome databases.
Allow patenting of genes to obtain further funding for sequencing research.
END OF PAPER 16