Oxford University Press | Online Resource Centre

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Question 1

Which of the following reactions is required for proofreading (i.e. correcting replication errors) during DNA replication by DNA polymerase III?

a) 3' - 5' exonuclease activity

b) 5' - 3' exonuclease activity

c) 3' - 5' endonuclease activity

d) 5' - 3' endonuclease activity

Question 2

How does the mismatch repair system distinguish between the parental (i.e. correct) DNA strand and the newly synthesised strand containing the mismatched base?

a) Thymine in the parental strand of the helix is methylated at GATC.

b) Thymine in the new strand of the helix is methylated at GATC.

c) Guanine in the parental strand of the helix is methylated at GATC.

d) Guanine in the new strand of the helix is methylated at GATC.

Question 3

What is the name of the DNA repair system in E. coli in which dual incisions are made in the damaged part of the double helix, and a 12-13 base segment is removed and replaced with new DNA?

a) Mismatch repair

b) Base excision repair

c) Nucleotide excision repair

d) AP site repair

Question 4

Which of the following is the name of the human genetic disorder resulting from defects in nucleotide excision repair?

a) Hereditary nonpolyposis colorectal cancer (HNPCC)

b) Xeroderma pigmentosum (XP)

c) Lynch syndrome

d) Diabetes

Question 5

In which of the following would you find telomeres?

a) Human mitochondrial DNA

b) Human chromosomes

c) Bacterial chromosomes

d) The influenza virus genome

Oxford University Press, Online Resource Centre, Chapter 22.

Chapter 22

Instructions

Question 1

Question 2

Question 3

Question 4

Question 5