試題詳解

15. Which one of the following statements about mRNA stability is true?
(A) Degradation always proceeds in the 5' to 3' direction.
(B) Degradation of mRNA by polynucleotide phosphorylase yields 5'-nucleoside monophosphates.
(C) In general, bacterial mRNAs have longer half-lives than do eukaryotic mRNAs.
(D) Rates of mRNA degradation are always at least ten-fold slower than rates of mRNA synthesis.

(E) Secondary structure in mRNA (hairpins, for example) slows the rate of degradation.