a. When it appears in messenger RNA, it is a signal to stop protein biosynthesis.
b. When it appears in transfer RNA, it is a signal to stop transferring amino acids to the growing protein chain.
c. When it appears in DNA, it is a signal to stop chromosome biosynthesis.
d. When it appears in a protein, it is a signal for the protein to unfold.
e. When it appears in ribosomal RNA, it is a signal to stop catalyzing protein biosynthesis.