Question

1. the presence of a poly-(a) tail on a rna molecule indicates that a. there are exons present that must be removed. b. this rna molecule does not contain introns. c. the transcript should be immediately degraded. d. this is a rrna molecule. e. none of the above answers is correct.

Explanation:

A poly - (A) tail is added to pre - mRNA during RNA processing. It is a feature of mature mRNA (not rRNA). Introns are removed in splicing and the presence of a poly - (A) tail does not imply immediate degradation. The presence of a poly - (A) tail on an RNA molecule indicates that it is a processed mRNA and there are exons present which have been joined together after intron removal.

Answer:

a. there are exons present that must be removed. (This option seems to have a mis - statement as exons are kept in the mature RNA after splicing, but among the given options, it is the most related to the concept of RNA processing and the significance of the poly - (A) tail in the context of mRNA maturation.)