Which DNA strand grows continuously towards the replication fork during DNA replication?

• A. Template strand
• B. Okazaki fragment
• C. Lagging strand
• D. Leading strand

Answer: (D)

Verified step by step guidance

1. Understand the process of DNA replication: DNA replication is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules. It occurs in the S phase of the cell cycle.
2. Identify the role of the replication fork: The replication fork is the area where the DNA double helix is unwound to allow the replication machinery to access the strands for copying.
3. Differentiate between the leading and lagging strands: During DNA replication, the two strands of DNA are copied in different ways. The leading strand is synthesized continuously in the direction of the replication fork, while the lagging strand is synthesized in short segments called Okazaki fragments, away from the replication fork.
4. Recognize the directionality of DNA synthesis: DNA polymerase, the enzyme responsible for synthesizing new DNA strands, can only add nucleotides to the 3' end of a growing DNA strand. This means that the leading strand is synthesized in a 5' to 3' direction towards the replication fork.
5. Conclude that the leading strand is the one that grows continuously towards the replication fork during DNA replication, as it is synthesized in the same direction as the unwinding of the DNA helix.