How does bidirectional replication differ from unidirectional replication?

How does bidirectional replication differ from unidirectional replication?

• A. In bidirectional replication, two forks extend from the origin in opposite directions
• B. Bidirectional replication uses a single fork that moves in one direction
• C. Bidirectional replication proceeds inward toward the origin
• D. Bidirectional replication occurs only in eukaryotes

Answer: (A)

Bidirectional replication means replication starts at an origin and proceeds in two directions, forming two replication forks that move away from the origin. In a bacterial circular chromosome, these forks travel in opposite directions around the circle and eventually meet, completing the copy. In eukaryotes, the same idea applies at each origin: two forks move outward in opposite directions along the chromosome. This is why the best description is two forks extending from the origin in opposite directions. The other statements describe unidirectional replication, forks moving toward the origin, or replication being exclusive to eukaryotes, which aren’t accurate.

Bidirectional replication means replication starts at an origin and proceeds in two directions, forming two replication forks that move away from the origin. In a bacterial circular chromosome, these forks travel in opposite directions around the circle and eventually meet, completing the copy. In eukaryotes, the same idea applies at each origin: two forks move outward in opposite directions along the chromosome. This is why the best description is two forks extending from the origin in opposite directions. The other statements describe unidirectional replication, forks moving toward the origin, or replication being exclusive to eukaryotes, which aren’t accurate.