Question

RNA polymerase ______.

Options

• can produce several polypeptide chains at one time through the creation of polysomes.

• starts transcribing at an AUG triplet on one DNA strand.

• transcribes both introns and exons.

• transcribes both DNA strands, but always in a 5’ → 3’ direction.

Answer 1

RNA polymerase transcribes both introns and exons.

Explanation:

RNA polymerase is the enzyme responsible for transcription, which is the process of copying a DNA sequence into a primary RNA transcript (pre-mRNA). In eukaryotic cells, most genes are composed of coding regions called exons and non-coding regions called introns. RNA polymerase does not distinguish between these during transcription; it simply reads the entire gene sequence and produces a continuous RNA strand that contains both. The removal of introns occurs only afterwards, during a separate step called RNA splicing.