Question

which of the following best describes the role of rna polymerase in a cell?
a. it initiates translation of mrna at the start codon for protein synthesis.
b. it attaches to a dna strand and unzips the molecule into two separate strands.
c. it reads the dna molecule for synthesis of a complementary strand of mrna.
d. it modifies an mrna transcript by adding a poly - a tail and removing introns.

Explanation:

RNA polymerase is involved in transcription. During transcription, it binds to the DNA, reads the DNA sequence, and synthesizes a complementary mRNA strand. Option A is about the role of ribosomes (not RNA polymerase) in translation. Option B is more related to helicase (not RNA polymerase) which unzips DNA. Option D describes post - transcriptional modification processes (like mRNA processing) which are not the main role of RNA polymerase. RNA polymerase's key function is mRNA synthesis from DNA as described in option C.

Answer:

C. It reads the DNA molecule for synthesis of a complementary strand of mRNA.