DNA strand

 

 Absolutely! Let’s break down the diagram and the concept of DNA replication at the replication fork, especially focusing on why D ➔ B is the leading strand.

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DNA Replication Basics

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• DNA strands run antiparallel (one runs 5’ → 3’, the other 3’ → 5’).
• DNA polymerase can only add new nucleotides in the 5’ to 3’ direction.
• The replication fork is the area where the double helix is unwound to expose the two single strands for copying.

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Leading vs. Lagging Strand

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When the fork opens up:

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Leading Strand

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• Synthesized continuously in the same direction as the replication fork is moving.
• New nucleotides are added one after another — smooth, no breaks.
• Uses the 3’ to 5’ template strand so that it can build 5’ to 3’.

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Lagging Strand

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• Synthesized in the opposite direction of the replication fork movement.
• Made in short segments called Okazaki fragments.
• Each fragment is later joined by enzymes.

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In Your Diagram

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