Which of the following is not true of RNA processing?

a. Exons are cut out before mRNA leaves the nucleus.

b. Nucleotides may be added at both ends of the RNA.

c. Ribozymes may function in RNA splicing.

d. RNA splicing can be catalyzed by spliceosomes.

A

Explanation:

Exons are what are needed in the processing mRNA hence cannot be cut out. The regions that are cut out are introns and mainly emanate from non-protein-coding region of DNA. During RNA processing the mRNA is capped at the 5' end and three (3) adenine nucleotides are added on 3' end of the RNA - in a process called polyadenylation - to stabilize the mRNA. This processing is carried out by enzymes such as ribozymes and spliceosomes. RNA requires to be processed before it exits the nucleus.