Question

Which of the following is found on the primary product of transcription but not on a mature mRNA molecule?

a) Intron
b) Exon
c) 5' cap
d) Poly(A) tail
e) Ribosome binding site

Answer 1

The 5' cap and poly-A tail are modifications found on the primary product of transcription but not on a mature mRNA molecule. They protect the mRNA from degradation and signal the need for export to the cytoplasm.

Step-by-step explanation:

The 5' cap and poly-A tail are modifications that are found on the primary product of transcription but not on a mature mRNA molecule.

The 5' cap is a modified nucleotide that is added to the 5' end of the growing transcript. It helps protect the mRNA from degradation and is recognized by factors involved in translation initiation by ribosomes.

The poly-A tail is a string of approximately 200 adenine nucleotides that is added to the 3' end of the transcript. It also protects the mRNA from degradation and signals the need for export to the cytoplasm.