Greater numbers of base changes are found in mRNA than in replicated DNA from the same gene sequence, because RNA polymerase
A) does not proofread.
B) uses UTP instead of thymidine triphosphate (TTP).
C) uses only one strand as its template.
D) is not processive.
E) catalyzes the addition of nucleotides in the 3′-to-5′ direction.

Question

Quizplus · Accepted Answer

RNA polymerase does not have proofreading capability and therefore, errors in base pairing are not corrected. This results in an increased number of base changes in mRNA compared to the original DNA sequence. Choice B is incorrect because RNA polymerase uses UTP instead of TTP, but this does not result in an increased number of base changes. Choice C is incorrect because both DNA polymerase and RNA polymerase use only one strand as their template. Choice D is incorrect because RNA polymerase is processive. Choice E is incorrect because RNA polymerase catalyzes the addition of nucleotides in the 5′-to-3′ direction, not the 3′-to-5′ direction.

Greater Numbers of Base Changes Are Found in MRNA Than