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

E. None of the above

Explanation:

During transcription, a sequence called a polyadenylation signal occurs in an RNA molecule, an enzyme at that site chops the RNA in two. The enzyme adds to the cut end around 100-200 adenine (A) nucleotides which form a poly-A tail at 3' end. The tail make transcript which is more stable and functions to be exported to the cytosol from the nucleus. Some sections of the RNA transcript (introns) are deleted when splicing, and the remaining sections (exons) are kept together.

Hence, the corrcet option is E.

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