Question

16
which of the following help protect us from mutations?
all of these
base excision repair
nucleotide excision repair
mismatch repair
17
what is a key difference between prokaryotic and eukaryotic chromosomes?
prokaryotic chromosomes are circular; eukaryotic chromosomes are linear
prokaryotic chromosomes are found in the nucleus
prokaryotic chromosomes are coiled on histones; eukaryotic chromosomes are supercoiled
prokaryotic chromosomes are linear; eukaryotic chromosomes are circular
18
which of the following proteins would not be found at a replication fork?
endonuclease
dna polymerase
helicase
primase

Explanation:

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Base excision repair, nucleotide excision repair, and mismatch repair are all DNA repair mechanisms that correct errors in DNA which can cause mutations. So all of these help protect from mutations.

Prokaryotic chromosomes (like in bacteria) are circular. Eukaryotic chromosomes (in organisms like animals, plants) are linear. Prokaryotes don't have a nucleus (so B is wrong). Eukaryotic chromosomes are coiled on histones (so C is wrong). Prokaryotic chromosomes are not linear (so D is wrong).

At a replication fork, helicase unwinds DNA, DNA polymerase synthesizes new DNA strands, primase makes RNA primers. Endonuclease is more involved in cutting DNA (e.g., in some repair or restriction enzyme - like processes, not typically at the replication fork).

Answer:

A. All of these

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