Genetic Material and Regulation of Gene Expression
Multiple Choice Questions and Answers
1. DNA replication is aided by
(a) DNA polymerases only
(b) DNA ligase only
(c) Both DNA polymerase and ligase
(d) RNA polymerase
Answer: (c) Both DNA polymerase and ligase
2. Pyrimidines present in RNA are
(a) cytosine and thymine
(b) adenine and guanine
(c) cytosine and uracil
(d) thymine and uracil
Answer: (c) cytosine and uracil
3. Left handed DNA is known as
(a) B-DNA
(b) Z- DNA
(c) both are similar
(d) none of the above
Answer: (b) Z- DNA
4. Who amongst the following discovered genetic nature of RNA?
(a) Frederich Miescher
(b) Hershey and Chase
(c) Griffith
(d) H Fraenkel-Conrat
Answer: (d) H Fraenkel-Conrat
5. Since the two original strands of DNA retained in the products formed as a result of DNA replication, it is called
(a) conservative
(b) semi conservative
(c) dispersive
(d) transcription
Answer: (b) semi conservative
6. Which of the following types of RNA occurs in largest amount amongst cell RNAs?
(a) mRNA
(b) Trna
(c) sRNA
(d) rRNA
Answer: (d) rRNA
7. A nucleoside is
(a) base + sugar
(b) base+ phosphate
(c) sugar+ phosphate
(d) base+ sugar+ phosphate
Answer: (a) base + sugar
8. The experimental system used in the studies on the discovery of replication of DNA has been
(a) Drosophila melanogaster
(b) Pneumococcus
(c) Escherichia coli
(d) Neurospora crassa
Answer: (c) Escherichia coli
9. The enzyme which catalyzes the formation of RNA from DNA template is known as
(a) reverse transcriptase
(b) RNA polymerase
(c) DNA polymerase
(d) Nuclease
Answer: (b) RNA polymerase
10. The details of the structure of RNA was given by
(a) Holley
(b) Hoagland
(c) Watson and Crick
(d) Beadle and Tatum
Answer: (a) Holley
11. The terms like cistron, muton and recon were coined by
(a) Johanssen
(b) Waldeyer
(c) Benzer
(d) Mathaei
Answer: (c) Benzer
12. DNA was first discovered by
(a) Beadle and Tatum
(b) Watson and Crick
(c) Friedrich Miescher
(d) A. Kornberg
Answer: (c) Friedrich Miescher
13. DNA differs from RNA
(a) in the nature of sugar alone
(b) in the nature of purines alone
(c) in the nature of sugars and pyrimidines
(d) none of the above
Answer: (c) in the nature of sugars and pyrimidines
14. The two strands of DNA are
(a) similar in nature and complimentary
(b) antiparallel and complimentary
(c) basically different in nature
(d) parallel and complementary
Answer: (b) antiparallel and complimentary
15. DNA is
(a) always double-stranded
(b) rarely single stranded
(c) always single stranded
(d) rarely double-stranded
Answer: (b) rarely single stranded
16. The similarity between DNA and RNA is that both
(a) are double stranded
(b) have similar sugars
(c) are polymers of nucleotides
(d) have similar pyrimidines
Answer: (c) are polymers of nucleotides
17. Ligase enzyme is used for
(a) joining bits of DNA
(b) splitting DNA thread into small bits
(c) denaturation
(d) none of the above
Answer: (a) joining bits of DNA
18. Phosphoric esters and nucleosides are known as
(a) phosphoric acids
(b) nucleic acids
(c) nuclein
(d) nucleotides
Answer: (d) nucleotides
19. In which of the following, double-stranded RNA is present
(a) bacteria
(b) chloroplast
(c) mitochondria
(d) reovirus
Answer: (d) reovirus
20. Which of the following elements is not present in a nitrogenous base?
(a) nitrogen
(b) hydrogen
(c) carbon
(d) phosphorus
Answer: (d) phosphorus
21. Who was awarded Nobel Prize for synthesis of RNA?
(a) S.Ochoa
(b) A. Korenberg
(c) H. Khorana
(d) Nirenberg
Answer: (a) S.Ochoa
22. Which one of the following is widely distributed in the cell?
(a) DNA
(b) RNA
(c) chloroplast
(d) chromoplast
Answer: (b) RNA
23. DNA generally acts as template of
(a) only protein
(b) only DNA
(c) only RNA
(d) both RNA and DNA
Answer: (d) both RNA and DNA
24. Which of the following is the smallest RNA?
(a) mRNA
(b) rRNA
(c) tRNA
(d) chromosomal RNA
Answer: (c) tRNA
25. DNA synthesis is known as
(a) transformation
(b) transduction
(c) transcription
(d) replication
Answer: (d) replication
26. When isolated DNA extract is kept at 82 to 90 degree centigrade then
(a) it remains unaffected
(b) it changes to RNA
(c) it gets broken into 10 lakh pieces
(d) the double helical structure opens into two strands
Answer: (d) the double helical structure opens into two strands
27. Genetic information of an organism lies in
(a) nucleotide sequence
(b) sugars
(c) bonds
(d) none
Answer: (a) nucleotide sequence
28. The protein which helps to unwind DNA double helix during replication is
(a) DNA polymerase
(b) DNA gyrase
(c) helicase
(d) DNA topoisomerase
Answer: (c) helicase
29. Small fragments of DNA synthesized during replication of DNA are called
(a) nucleotides
(b) genes
(c) Okazaki fragments
(d) single-stranded DNA
Answer: (c) Okazaki fragments
30. Griffith gave experimental evidence to prove that DNA is a genetic material. His evidence was based on
(a) bacterial transformation
(b) bacterial transduction
(c) mutation
(d) all the above
Answer: (a) bacterial transformation
31. DNA synthesis can be specifically measured by estimating the incorporation of radio-labelled
(a) uracil
(b) adenine
(c) thymidine
(d) deoxyribose sugar
Answer: (c) thymidine
32. The following is needed for DNA replication
(a) DNA polymerase and DNA ligase
(b) RNA polymerase and translocase
(c) DNA polymerases only
(d) DNA ligase only
Answer: (a) DNA polymerase and DNA ligase
33. DNA generally acts as a template for the synthesis of
(a) only proteins
(b) only DNA
(c) only RNA
(d) both DNA and RNA
Answer: (a) only proteins
34. Circular DNA molecule occurs in
(a) viruses
(b) bacteria chloroplast and mitochondria
(c) bacteria and chloroplasts only
(d) bacteria only
Answer: (b) bacteria chloroplast and mitochondria
35. An antibiotic which inhibits the synthesis of RNA especially in regions which are rich in cytosine and guanine is
(a) actinomycin
(b) chloramphenicol
(c) mitomycin
(d) puromycin
Answer: (a) actinomycin
36. Nucleic acids were discovered by
(a) Watson and Crick
(b) HG Khorana
(c) M.H.F Wilkins
(d) F.Meischer
Answer: (d) F.Meischer
37. How many nucleotides are present in one turn of DNA helix?
(a) 4
(b) 8
(c) 10
(d) 9
Answer: (c) 10
38. Non genetic RNA is of
(a) two types
(b) three types
(c) only one type
(d) none of these
Answer: (b) three types
39. DNA replication is
(a) conservative
(b) non conservative
(c) semi conservative
(d) constitutive
Answer: (c) semi conservative
40. What is the type of coiling in DNA?
(a) right-handed
(b) left-handed
(c) Zig-zag
(d) none of these
Answer: (a) right-handed
41. The successive nucleotides of RNA are covalently linked through
(a) glycosidic bonds
(b) phosphodiester bonds
(c) hydrogen bonds
(d) none of these
Answer: (b) phosphodiester bonds
42. What is the similarity between DNA and RNA?
(a) both have same sugars
(b) both have same pyrimidines
(c) both can replicate
(d) none of these
Answer: (b) both have same pyrimidines
43. The tertiary structure of t-RNA is
(a) L-shaped
(b) X-shaped
(c) t-shaped
(d) Y-shaped
Answer: (a) L-shaped
44. Chargaff’s rule is applicable to
(a) single stranded DNA
(b) double stranded DNA
(c) single stranded RNA
(d) single stranded DNA and RNA
Answer: (a) single stranded DNA
45. Which form of RNA has a structure resembling clover leaf?
(a) t-RNA
(b) r-RNA
(c) hn-RNA
(d) m- RNA
Answer: (d) m- RNA
46. Transcription begins when one of the following enzymes binds to a promoter site
(a) DNA polymerase
(b) RNA polymerase
(c) helicase
(d) gyrase
Answer: (b) RNA polymerase
47. During transcription, the DNA site at which RNA polymerase binds is called
(a) promoter
(b) regulator
(c) receptor
(d) enhancer
Answer: (a) promoter
48. Which one of the following codons code for the same information as UGC?
(a) UGU
(b) UGA
(c) UAG
(d) UGC
Answer: (a) UGU
49. If the sequence of bases in DNA is ATTCGATG, then the sequence of bases in its transcript will be
(a) GUAGCUUA
(b) UAAGCUAC
(c) CAUCGAAU
(d) AUUCGAUG
Answer: (b) UAAGCUAC
50. In split genes, the coding sequences are called
(a) cistrons
(b) operons
(c) exons
(d) introns
Answer: (c) exons