Question

apply: gene expression and regulation
google classroom microsoft teams
the following diagram represents the flow of genetic information from dna to protein.
step 1 step 2 step 3
dna → pre - mrna → mrna → protein
which of the following describes an event that occurs during step 2 in the diagram?
choose 1 answer:
a pre - mrnas are produced by rna polymerase using a template molecule.
b trnas help add amino acids to a growing polypeptide chain.
c pre - mrnas are modified to include only certain exons.
d rrnas help translate mrnas in the cytosol.

Explanation:

To solve this, we analyze each option based on the steps of gene expression (DNA → Pre - mRNA (Step 1: Transcription) → mRNA (Step 2: RNA Processing) → Protein (Step 3: Translation)).

• Option A: Pre - mRNA production (transcription) is Step 1, not Step 2.
• Option B: tRNAs adding amino acids is part of translation (Step 3), not Step 2.
• Option C: Pre - mRNAs are modified (splicing to include certain exons) during RNA processing, which is Step 2.
• Option D: rRNAs translating mRNA is part of translation (Step 3), not Step 2.

Answer:

C. pre - mRNAs are modified to include only certain exons.