Question

1. Which piece of information is key to what is different between a poly-Q and a non-poly-Q disease?

A) DNA synthesis can make errors permanent if they aren't fixed before S-phase

B) Spo11 introduces double-stand breaks.

C) CAG is the codon for glutamine.

D) Homologous recombination can lead to gene conversion.

E) Strand slippage is more common with repetitive DNA sequences.

2. Mutations can occur through errors during S-phase and errors during M-phase. What is most commonly the difference between the mutations that these two kinds of errors create?

A) Errors in S-phase tend to create small-scale mutations; errors in M-phase tend to create large-scale mutations

B) Errors in S-phase tend to create insertions and deletions, while errors in M-phase tend to create substitutions.

C) Errors in S-phase tend to create transitions, while errors in M-phase tend to create transversions.

D) Errors in S-phase tend to be due to physical breakage, while errors in M-phase are most often due to chemical modifications.

E) Missense and nonsense mutations are more common in S-phase, while most mutations created in M-phase are most often silent.

Answer 1

Ans1)C) CAG is the codon for glutamine.

Explaination:CAG codon code for glutamine(Q) so CAG trinucleotide repeat disorder is known as polyQ diseases ie polyglutamine disorders. While other than CAG trinucleotides repeat disorder known as non poly Q disease.

Ans2)A) Errors in S-phase tend to create small-scale mutations; errors in M-phase tend to create large-scale mutations

Explaination:Errors in S-phase tend to create small-scale mutations ie, changes at DNAlevel in which one or few nucleotides of a gene are altered or affected while  errors in M-phase tend to create large-scale mutations ie, change at chromosomal level in which various or several nucleotides are involved.