Question

How many of eukaryotic RNA polymerase subunits are common for all three polymerases?

(a) 3

(b) 5

(c) 10

(d) 7

This question was addressed to me during an online interview.

Question is taken from Transcription in Eukaryotes : RNA Polymerases topic in chapter Gene Expression : Transcription Prokaryotes of Cytogenetics

Answer 1

The correct answer is (b) 5

For explanation I would say: The beta, beta prime, two alpha and one omega subunit homology to eukaryotic RNA polis common in all three RNA polymerases. These are RPA 1-5 respectively. The rest subunits are non-essential or dispensable.