Okazaki fragments and DNA synthesis In DNA metabolism, Okazaki fragments are characteristic intermediates that arise during which process?

Introduction:
DNA replication must copy antiparallel strands using polymerases that extend only in the 5 to 3 direction. This asymmetry forces one strand to be synthesized discontinuously as short DNA segments known as Okazaki fragments.

Given Data / Assumptions:

• DNA polymerases synthesize DNA by adding nucleotides to a 3 hydroxyl end.
• Replication forks are bidirectional with leading and lagging strands.
• Okazaki fragments are later joined by ligase to create a continuous lagging strand.

Concept / Approach:

The leading strand can be synthesized continuously toward the fork. The lagging strand runs in the opposite direction relative to polymerase polarity, requiring repeated priming and extension away from the fork, generating many short fragments that are processed into a continuous strand.

Step-by-Step Solution:

Verification / Alternative check:

Pulse labeling experiments and electron microscopy reveal short nascent DNA pieces on the lagging strand that mature into full length DNA after ligation.

Why Other Options Are Wrong:

Transformation is DNA uptake by cells. PCR uses continuous primer extension in vitro and does not generate classical lagging strand fragments. General protein synthesis and transcription do not involve DNA fragment ligation.

Common Pitfalls:

Assuming both strands are continuous or believing polymerases can extend 3 to 5. Another pitfall is confusing Okazaki fragments with RNA primers.

Final Answer:

Replication