A replication fork is shown with a leading and lagging strand. Helicase unwinds DNA at the fork.
Why is the lagging strand synthesized in short Okazaki fragments?
- A
The lagging strand uses a different polymerase that synthesizes 3' to 5'.
- Bcheck_circle
DNA polymerase only adds nucleotides 5' to 3', so the strand opposite to fork movement must be made discontinuously.
- C
RNA primers are not required on the lagging strand.
- D
Helicase repeatedly stops on the lagging strand template.
Explanation
DNA polymerase synthesizes only in the 5' to 3' direction. On the lagging-strand template, this requires repeated short syntheses (Okazaki fragments) that are later joined by ligase.