This set of Cell Biology Multiple Choice Questions & Answers focuses on “Between Replication and Repair”.
1. Which form of Xeroderma pigmentosum is observed in patients who cannot synthesize functional polymerase Η?
a) XP III
b) XP IV
c) XP V
d) XP VI
Explanation: Patients afflicted with a variant of Xeroderma pigmentosum, XP V are susceptible to developing skin cancer due to sun exposure. It is discovered that the gene encoding replicative polymerase Η.
2. Replicative polymerase Η belongs to a family of polymerases involved in ________________
a) translesion synthesis
b) mRNA localization
c) mRNA translation
d) mRNA stability
Explanation: The polymerase Η was discovered in 1999, it is a member of family of DNA polymerases having the function of incorporating nucleotides opposite particular types of DNA lesions in the template strand.
3. Which if the following polymerases have an unusually spacious active site?
a) DNA polymerases
b) TLS polymerases
c) RNA polymerases
d) DNA helicases
Explanation: Translesion synthesis (TLS) polymerases have an unusually spacious active site for accommodating altered nucleotides that would not fit in other replicative enzymes.
4. Translesion synthesis polymerases lack processivity.
Explanation: The translesion synthesis polymerases are only capable of incorporating one to a few nucleotides. They have no proofreading activity and also lack processivity.
Sanfoundry Global Education & Learning Series – Cell Biology.
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