Question

Which of the following is not true of RNA processing?

Options

• Exons are excised and hydrolysed before the mRNA moves out of the nucleus.

• An initial RNA transcript is much longer than the final RNA molecule that may leave the nucleus.

• RNA splicing may be catalysed by spliceosomes.

• The existence of exons and introns may facilitate crossing over between regions of a gene that code for polypeptide domains.

Answer 1

Exons are excised and hydrolysed before the mRNA moves out of the nucleus.

Explanation:

This statement is incorrect because introns (non-coding regions) are the segments that are excised and removed during RNA splicing, not exons. Exons are the essential coding sequences that are joined together to form the mature mRNA molecule, which then exits the nucleus to be translated into protein.