MCQs

Question 1

1. Within a eukaryote gene sequence, introns are:
   A. the sequence information that codes for a polypeptide
   B. sequences not transcribed
   C. sequences transcribed but not translated
   D. sequences necessary for replication
   E. sequences involved in DNA replication

Answer 1

C. sequences transcribed but not translated

Question 2

2. All polymerases make mistakes during nucleic acid replication, but the highest mutation rate due to replication errors are found in:  
A. prokaryotes  
B. RNA viruses       
C. DNA viruses  
D. eukaryotes  
E. prions.

Answer 2

B. RNA viruses

Question 3

3. During DNA replication, which enzyme joins Okazaki fragments together?  
A. DNA endonuclease  
B. DNA polymerase  
C. DNA ligase  
D. Taq 1  
E. DNA gyrase.

Answer 3

C. DNA ligase

Question 4

4. Approximately how much of a bacterial genome actually codes for cellular components? Select one of the following.  
A. 10%  
B. 30%  
C. 50%  
D. 70%  
E. 90%

Answer 4

E. 90%

Question 5

5. At what frequency do enol or imino forms of nucleotides bases occur in living cells?  
A. 1 in 106  
B. 1 in 105  
C. 1 in 104  
D. 1 in 103  
E. 1 in 102.

Answer 5

E. 1 in 102

Question 6

6. Which of the following statements describes modes of genetic transfer amongst the bacteria?
   A. conjugation and translocation
   B. transplantation and transformation
   C. transplantation and transduction
   D. conjugation, transduction, and transformation
   E. transplantation, transduction, and transformation.

Answer 6

D. conjugation, transduction, and transformation

Question 7

7. Bacterial gene expression is dependent on three main influences. Select from the following, which best describes those influences:
   A. rates of transcription and translation, and gene copy number
   B. rates of growth, mitosis and meiosis
   C. rates of nutrient uptake, metabolism and removal of waste from the bacterium
   D. rates of nucleotide, protein and fat synthesis
   E. rates of energy production, carbohydrate synthesis and cell death.

Answer 7

A. rates of transcription and translation, and gene copy number

Question 8

8. Which of the following statements about eukaryote gene enhancer sequences is correct?
   A. enhancers can be either side of a gene, at some distance from a gene, or even within a gene
   B. enhancers are located downstream of the genes which they regulate
   C. enhancers are located upstream of the genes which they regulate
   D. enhancers are always situated at a fixed distance from the site where transcription is initiated
   E. an enhancer can only affect the expression of a single specific gene.

Answer 8

A. enhancers can be either side of a gene, at some distance from a gene, or even within a gene

Question 9

9. The anterior-posterior axis in the early Drosophila embryo is established by concentration gradients of which proteins?  
A. NOS and BCD proteins  
B. NOS and HB-M proteins  
C. BCD and HB-M proteins  
D. BCD and CACT proteins  
E. HB-M and CACT proteins.

Answer 9

C. BCD and HB-M proteins

Question 10

10. Hox genes in mammalian embryos are expressed to:
    A. define segments in the developing somites (segmental units of the spinal column) and central nervous system
    B. determine the development of the brain and central nervous system only
    C. determine the development of the fore limbs only
    D. determine the development of the hind limbs only
    E. determine the anterior-posterior axis.

Answer 10

A. define segments in the developing somites (segmental units of the spinal column) and central nervous system

Question 11

11. Mutations can occur at the level of:  
A. DNA bases  
B. individual genes  
C. chromosomes  
D. the whole genome  
E. all of the above levels.

Answer 11

E. all of the above levels.

Question 12

12. Fragile X-syndrome results from changes in the FMR-1 gene due to:
    A. deletion of trinucleotide sequence, CGG
    B. duplication of trinucleotide sequence, CGG
    C. inversion of trinucleotide sequence, CGG
    D. translocation of trinucleotide sequence, CGG
    E. all the above.

Answer 12

B. duplication of trinucleotide sequence, CGG

Question 13

13. DNA repair using homologous recombination (HR) process takes place:
    A. shortly after S and G2 phases of the cell cycle
    B. only in the S phase of the cell cycle
    C. in mitotic phase of the cell cycle
    D. in G1 phase of the cell cycle
    E. at any phase of the cell cycle.

Answer 13

A. shortly after S and G2 phases of the cell cycle

Question 14

14. The p53 gene is:
    A. a tumour suppressor gene
    B. known as ‘guardian of the genome’
    C. mutated in approximately 60% of cancers
    D. involved in a check point at the G1/ S border
    E. all the above.

Answer 14

E. all the above.

Question 15

15. For biomonitoring purposes, singe cell gel electrophoresis or comet assay is used to evaluate:
    A. chromosomal aberrations and aneuploidy
    B. mutations in specific genes
    C. DNA strand breaks
    D. sister chromatid exchanges (SCEs)
    E. DNA adducts.

Answer 15

C. DNA strand breaks

Question 16

16. Which of the following base analogues is required when cells are grown under in vitro conditions for the analysis of sister chromatid exchanges (SCEs) for biomonitoring purposes?  
A. 5-bromodeoxyuridine (BrdU or BudR)  
B. uridine  
C. inosine  
D. all of the above  
E. none of the above.

Answer 16

A. 5-bromodeoxyuridine (BrdU or BudR)

Question 17

17. The maximum insert size in bacteriophage Lambda cloning vectors is:   
A. 100 kilobase pairs of DNA  
B. 5 kilobase pairs of DNA  
C. 15 kilobase pairs of DNA  
D. 25 kilobase pairs of DNA  
E. 50 kilobase pairs of DNA.

Answer 17

D. 25 kilobase pairs of DNA

Question 18

18. Which genetic marker is commonly incorporated into plasmid cloning vectors to facilitate selection of host bacteria containing the plasmid?  
A. antibiotic resistance  
B. antibody sensitivity  
C. analogue sensitivity  
D. anaerobic resistance  
E. catabolite repressor.

Answer 18

A. antibiotic resistance

Question 19

19. Copy or complementary DNA (cDNA) production from eukaryotes and cloning of this cDNA in bacteria gets over the problem of …?  
A. exons  
B. introns  
C. ions  
D. neons  
E. freons.

Answer 19

B. introns

Question 20

20. The polymerase chain reaction (PCR) does one of the following to targeted DNA sequences:  
A. translates the DNA  
B. amplifies the DNA  
C. transcribes the DNA  
D. deletes the DNA  
E. degrades the DNA.

Answer 20

B. amplifies the DNA

Question 21

21. A fusion between two different cloned genes is known as a:   
A. gene chimera  
B. gene merger  
C. gene joint  
D. gene wrap  
E. giant gene

Answer 21

A. gene chimera

Question 22

22. The world’s first cloned (genetically engineered) human product for medicinal use was:  
A. insulin  
B. alpha trypsin  
C. antibody  
D. somatastatin  
E. interferon.

Answer 22

A. insulin

Question 23

23. An advantage that yeasts have over Escherichia coli as gene cloning hosts, is that yeasts do not produce toxic:   
A. teichoic acid  
B. proteases  
C. carbohydrates  
D. lipopolysaccharides  
E. lipids.

Answer 23

D. lipopolysaccharides

Question 24

24. An animal or plant which has foreign gene(s) introduced into its genetic make-up so that it passes on those genes to its offspring is known as:   
A. transallelic  
B. transformed  
C. transmutable  
D. transgenomic  
E. transgenic.

Answer 24

E. transgenic.

Question 25

25. Which of the following statements relating to genetic diversity in mammals is correct? Mammals are typically: A. polymorphic at 10% of gene loci and heterozygous at 5% B. polymorphic at 25% of gene loci and heterozygous at 5% C. polymorphic at 25% of gene loci and heterozygous at 15% D. polymorphic at 40% of gene loci and heterozygous at 5% E. polymorphic at 40% of gene loci and heterozygous at 15%

Answer 25

B. polymorphic at 25% of gene loci and heterozygous at 5%

Question 26

``` 26. The effective population size (Ne) of the mitochondrial genome compared to that of the nuclear genome is: A. 25% B. 50% C. the same D. 200% E. unknown. ```

Answer 26

A. 25%

Question 27

27. Comparisons can be made of the human karyotype with the karyotypes of other primates. Which of the following statements best describes the use of karyotypes to provide information about the primate phylogenetic tree? A. karyotypes cannot be used for this purpose B. they give only an approximation of both branching order and the dates when these occurred C. they provide robust information on the timing of genetic changes, but, because of overall similarity, can only give a vague approximation of branching order D. they provide robust information about both the branching order and the dates in primate evolution E. they provide robust information about the branching order in primate evolution, but no information about the dates.

Answer 27

E. they provide robust information about the branching order in primate evolution, but no information about the dates.

Question 28

``` 28. Fossil and archaeological evidence suggest that modern humans expanded out of Africa whenever the climate allowed. However, it appears that only expansions after a certain date have contributed to modern human populations. That date is: A. 100 KYA B. 80 KYA C. 60 KYA D. 40 KYA E. 20 KYA. ```

Answer 28

D. 40 KYA

Question 29

29. Acculturation and demic diffusion are two alternative models to account for the spread of agriculture. Which of the following statements is consistent with the demic diffusion model for the spread of agriculture in Europe from a near East origin? A. hunter gatherers in Europe adopt farming from their neighbours B. hunter gatherers in Europe adopt farming and languages from their neighbours C. farmers move in, adopt the hunter gatherer languages, out-compete the hunter gatherers, expand, and move on D. farmers move in, there is no admixture with hunter gatherers, out-compete the hunter gatherers, expand, and move on E. farmers move in, there is no admixture with hunter gatherers, and the hunter gatherers move on.

Answer 29

B. hunter gatherers in Europe adopt farming and languages from their neighbours

Question 30

30. Linkage disequilibrium may result from admixture of two populations. The amount of linkage disequilibrium will: A. reduce by 50% each generation B. reduce by an amount equal to the recombination fraction each generation C. reduce by an unspecified amount determined solely by genetic drift D. fluctuate randomly between successive generations E. persist indefinitely over many generations.

Answer 30

B. reduce by an amount equal to the recombination fraction each generation