DNA is replication in which of the following directions?

• A. 5' to 3'
• B. 3' to 5'
• C. 5' to 5'
• D. 3' to 3'

Answer: (A)

Verified step by step guidance

1. Understand that DNA replication involves the synthesis of a new DNA strand complementary to the template strand.
2. Recall that DNA polymerases, the enzymes responsible for DNA synthesis, can only add nucleotides to the 3' end of a growing DNA strand.
3. Recognize that this means DNA synthesis occurs in the 5' to 3' direction, as nucleotides are added to the 3' end.
4. Consider the antiparallel nature of DNA strands, where one strand runs 5' to 3' and the complementary strand runs 3' to 5'.
5. Conclude that during replication, the new strand is synthesized in the 5' to 3' direction, matching the directionality of DNA polymerase activity.