Genetic Material and Regulation of Gene Expression (Multiple Choice Questions and Answers)

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





Answer: (b) UAAGCUAC

50. In split genes, the coding sequences are called

(a) cistrons

(b) operons

(c) exons

(d) introns

Answer: (c) exons