Question

An RNA chain elongates in what direction? Choose one:

A. It depends on which DNA strand acts as the template.
B. 5'-to-3' only
C. 3'-to-5' only
D. It depends on which RNA polymerase does the transcribing.

Answer 1

An RNA chain elongates in the 5'-to-3' direction, with the process being mediated by RNA polymerase that synthesizes the RNA using the 3'-to-5' DNA template strand as a guide.

Step-by-step explanation:

An RNA chain elongates in the 5'-to-3' direction. This elongation process is facilitated by an enzyme known as RNA polymerase, which aligns and adds the correct nucleic acids to the growing RNA strand by complementary base pairing with the template DNA strand. The template DNA strand is read in the 3'-to-5' direction, which allows the RNA to be synthesized in the 5'-to-3' direction. This directionality is consistent regardless of which DNA strand acts as the template or which RNA polymerase is doing the transcribing. Therefore, the correct answer is B. 5'-to-3' only.