1. Amino acid sequence, in
protein synthesis is decided by the sequence of
(a) rRNA (b) tRNA
(c) mRNA (d) cDNA
2. Antiparallel strands of a
DNA molecule means that
(a) one strand turns clockwise
(b) one strand turns anti-clockwise
(c) the phosphate groups of two DNA strands, at
their ends, share the same position
(d) the phosphate groups at the start of two
DNA strands are in opposite position (pole).
3. Polysome is formed by
(a) a ribosome with several subunits
(b) ribosomes attached to each other in a
linear arrangement
(c) several ribosomes attached to a single mRNA
(d) many ribosomes attached to a strand of
endoplasmic reticulum.
4. In the DNA molecule
(a) the proportion of adenine in relation to
thymine varies with the organism
(b) there are two strands which run
antiparallel—one in 5l " 3l direction and other in 3l " 5l
(c) the total amount of purine nucleotides and
pyrimidine nucleotides is not always equal
(d) there are two strands which run parallel in
the 5l " 3l direction.
5. What is not true for genetic
code?
(a) It is nearly universal.
(b) It is degenerate.
(c) It is unambiguous
(d) A codon in mRNAt is read in a
non-contiguous fashion.
6. Removal of introns and
joining the exons in a defined order in a transcription unit is called
(a) tailing (b) transformation
(c) capping (d) splicing
7. The net electric charge on
DNA and histones is
(a) both positive (b) both negative
(c) negative and positive, respectively (d) zero
8. Gene controls
(a) protein synthesis but not heredity
(b) protein synthesis and heredity
(c) heredity but not protein synthesis
(d) biochemical reaction of some enzymes
9. The promoter site and the
terminator site for transcription are located at
a) 3' (downstream) end and 5'
(upstream) end, respectively of the transcription unit
(b) 5' (upstream) end and 3' (downstream) end,
respectively of the transcription unit
(c) the 5' (upstream) end
(d) the 3' (downstream) end
10. Which of the following statements is the
most appropriate for sickle cell anaemia?
(a) It cannot be treated with iron supplements
(b) It is a molecular disease
(c) It confers resistance to acquiring malaria
(d) All of
the above
11. With regard to mature mRNA in eukaryotes
(a) exons and introns do not appear in the
mature RNA
(b) exons appear but introns do not appear in
the mature RNA
(c) introns appear but exons do not appear in
the mature RNA
(d) both exons and introns appear in the mature
RNA
12. The human chromosome with the
highest and least number of genes in them are respectively
(a) Chromosome 21 and Y (b) Chromosome 1 and X
(c) Chromosome 1 and Y (d) Chromosome X and Y
13. Who amongst the following
scientists had no contribution in the development of the double
helix model for the structure
of DNA?
(a) Rosalind Franklin (b) Maurice Wilkins
(c) Erwin Chargaff (d) Meselson and Stahl
14. DNA is a polymer of
nucleotides which are linked to each other by 3′→ 5′ phosphodiester bond. To prevent
polymerisation of nucleotides, which of the following modifications would you
choose?
(a) Replace purine with pyrimidines
(b) Remove/replace 3' OH group in deoxyribose
(c) Remove/replace 2' OH group with some other
group in deoxyribose
(d) Both ‘b’ and ‘c’
15. Discontinuous synthesis of
DNA occurs in one strand, because
(a) DNA molecule being synthesised is very long
(b) DNA dependent DNA polymerase catalyses
polymerisation only in one direction (5′ → 3′)
(c) it is a more efficient process
(d) DNA ligase joins the short stretches of DNA
16. Which of the following
steps in transcription is catalysed by RNA polymerase?
(a) Initiation (b) Elongation
(c) Termination (d) All of the above
17. Control of gene expression
in prokaryotes take place at the level of
(a) DNA-replication (b) Transcription
(c) Translation (d) None of the above
18. Which of the following
statements is correct about the role of regulatory proteins in
transcription in prokaryotes?
(a) They only increase expression
(b) They only decrease expression
(c) They interact with RNA polymerase but do
not affect the expression
(d) They can act both as activators and as
repressors
19. Which was the last human
chromosome to be completely sequenced?
(a) Chromosome 1 (b) Chromosome 11
(c) Chromosome 21 (d) Chromosome X
20. Which of the following are
the functions of RNA?
(a) It is a carrier of genetic information from
DNA to ribosomes synthesising polypeptides.
(b) It carries amino acids to ribosomes.
(c) It is a constituent
component of ribosomes.
(d) All of the above.
21. While analysing the DNA of
an organism a total number of 5386 nucleotides were found, out of which the
proportion of different bases were: Adenine = 29%, Guanine = 17%, Cytosine = 32%,Thymine
= 17%.Considering the Chargaff’s rule it can be concluded that
(a) it is a double stranded circular DNA (b) it is single stranded DNA
(c) it is a double stranded linear DNA (d) no conclusion can be drawn
22. In some viruses, DNA is
synthesised by using RNA as template. Such a DNA is called
(a) A-DNA (b) B-DNA (c) cDNA (d) rDNA
23. If Meselson and Stahl's
experiment is continued for four generations in bacteria, the ratio of N15/N15:
N15/N14: N14/N14 containing DNA in the fourth generation would be
(a) 1:1:0 (b) 1:4:0 (c) 0:1:3 (d) 0:1:7
24. If the sequence of nitrogen
bases of the coding strand of DNA in a transcription unit is:
5' - A T G A A T G - 3', the
sequence of bases in its RNA transcript would be
(a) 5' - A U G A A U G - 3' (b) 5' - U A C U U A C - 3'
(c) 5' - C A U U C A U - 3' (d) 5' - G U A A G U A - 3'
25. In E.coli, the lac operon
gets switched on when
(a) lactose is present and it binds to the
repressor
(b) repressor binds to operator
(c) RNA polymerase binds to the operator
(d) lactose is present and it binds to RNA
polymerase
