Processing of a primary mRNA transcript in a eukaryotic cell does NOT normally involve:
A) attachment of a long poly(A) sequence at the 3' end.
B) conversion of normal bases to modified bases, such as inosine and pseudouridine.
C) excision of intervening sequences (introns).
D) joining of exons.
E) methylation of one or more guanine nucleotides at the 5' end.

Question

Quizplus · Accepted Answer

Conversion of normal bases to modified bases, such as inosine and pseudouridine, is a rare occurrence and not a normal step in mRNA processing. The other choices (A, C, D, and E) are all typical steps in eukaryotic mRNA processing. Attachment of a poly(A) sequence at the 3' end, excision of intervening sequences (introns), joining of exons, and methylation of one or more guanine nucleotides at the 5' end are all necessary for the formation of functional mRNA molecules in eukaryotic cells.

Processing of a Primary MRNA Transcript in a Eukaryotic Cell