What is the replication fork?

• A. A Y-shaped region on a replicating DNA molecule where new strands are growing
• B. The enzyme that unwinds DNA
• C. The site where RNA primers are laid down
• D. The point where replication ends

Answer: (A)

The replication fork is the Y-shaped region where the double helix is unwound and new DNA strands begin to grow. As replication starts, enzymes like helicase open up the two DNA strands, creating two single‑stranded templates. On this fork, DNA polymerases synthesize new DNA: one strand is made continuously toward the fork (leading strand), while the other is made in short segments away from the fork (lagging strand), later joined to form a complete, new double helix. The other options refer to distinct components: the enzyme that unwinds DNA is helicase; the RNA primers are laid down by primase at the start of each fragment; and replication ends at the termination point.