A new DNA strand elongates only in the 5' to 3' direction because
A) DNA polymerase begins adding nucleotides at the 5' end of the template.
B) Okazaki fragments prevent elongation in the 3' to 5' direction.
C) replication must progress toward the replication fork.
D) DNA polymerase can only add nucleotides to the free 3' end.

Question

Quizplus · Accepted Answer

DNA polymerase can only add nucleotides to the free 3' end of a pre-existing strand, thus elongation can only occur in the 5' to 3' direction.

A New DNA Strand Elongates Only in the 5' to 3