Question

Which of the following best explains why only pre-mRNA is recognized and receives a 5' cap?

a) The 5' cap enhances transcription efficiency.
b) The 5' cap protects the pre-mRNA from degradation.
c) The 5' cap helps in the export of pre-mRNA from the nucleus.
d) The 5' cap facilitates recognition by the ribosome during translation.
e) The 5' cap signals the initiation of splicing.

Answer 1

The 5' cap on pre-mRNA serves to protect it from degradation, facilitate its export from the nucleus, and assist in the initiation of translation by ribosomes.

Step-by-step explanation:

The 5' cap added to pre-mRNA plays several important roles. Firstly, it protects the pre-mRNA from degradation. This is crucial because pre-mRNA are vulnerable to enzymatic degradation in the cell. Secondly, the cap helps in the export of pre-mRNA from the nucleus to the cytoplasm.

It serves as a signal for export factors to recognize and transport the pre-mRNA. Lastly, the cap facilitates recognition by the ribosome during translation. Factors involved in protein synthesis recognize the cap and help initiate translation by ribosomes.