DNA Structure and Replication – Section 2

16. 30 nm wide helix with five or six nucleosomes per helix is known as

A. solenoid
B. halonoid
C. kinoplast
D. none of these

Correct Answer: A. solenoid

17. Which of the following is used to determine the appropriate stringency (Wallace rule)?

A. Tm = 2 x (No.of G:C base pair) + 4 x (No.of A:T base pair)
B. Tm = 4 x (No.of A:T base pair) + 2 x (No.of G:C base pair)
C. Tm = 4 x (No.of G:C base pair) + 2 x (No.of A:T base pair)
D. Tm = 69.3° + 0.41 (%)G+C -650/1

Correct Answer: C. Tm = 4 x (No.of G:C base pair) + 2 x (No.of A:T base pair)

18. One hypothesis of DNA replication suggested that the parental DNA molecules are broken into fragments. Both strands of DNA in each of the daughter molecules are made up of an assortment of parental and new DNA. This statement refers to which hypothesis?

A. Conservative theory
B. Dispersive theory
C. Semi-conservative theory
D. Evolutionary theory

Correct Answer: B. Dispersive theory

19. DNA polymerases I also has

A. 5′-3′ exonuclease activity
B. 3′-5’exonuclease activity
C. both (a) and (b)
D. 5′-3′ endonuclease activity

Correct Answer: B. 3′-5’exonuclease activity

20. Without telomerase, what would happen to the ends of chromosomes after each round of replication?

A. Chromosomes would become progressively shorter
B. Nothing would happen
C. Chromosomes would get longer
D. none of the above

Correct Answer: A. Chromosomes would become progressively shorter

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