The XPC-Rad23B complex recognizes the distortions produced by these defects. For 10 points each:
[10m] Name these bulky lesions that cause polymerase stalling. Defects in NER (“N-E-R”) cause these defects to accumulate at a rate of thousands per minute.
ANSWER: pyrimidine dimers [accept thymine dimers, TT photodimers, 6–4 photoproducts, cyclobutane pyrimidine dimers, or CPDs; prompt on errors or mutations or photodimers]
[10h] This process, which is triggered by PCNA ubiquitination, uses Hoogstein base pairing to add adenines across from unrepaired dimers. Polymerases used in this process, which include zeta, eta, and iota, persist despite poor fidelity and low processivity.
ANSWER: translesion synthesis [or TLS; accept translesion bypass]
[10e] Two answers required. Non-canonical pairing contrasts with the system named for these scientists, which places the base ring anti. These two scientists were the first to publish the structure of DNA.
ANSWER: James Watson AND Francis Crick [accept answers in either order; accept Watson–Crick base pairing; accept James Dewey Watson in place of “James Watson”; accept Francis Harry Compton Crick in place of “Francis Crick”]
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