AP BIOLOGY

Detailed explanation-1: -Replication fork is the junction between the newly separated DNA template strands and the adjacent unreplicated DNA duplex. It is different from the origin of replication (ori site) in that ori site merely includes the first sequence of DNA on the template to get copied during DNA replication.

Detailed explanation-2: -Figure 9.10 A replication fork is formed by the opening of the origin of replication, and helicase separates the DNA strands. An RNA primer is synthesized, and is elongated by the DNA polymerase.

Detailed explanation-3: -The double-stranded DNA of the circular bacteria chromosome is opened at the origin of replication, forming a replication bubble. Each end of the bubble is a replication fork, a Y-shaped junction where double-stranded DNA is separated into two single strands.

Detailed explanation-4: -DNA helicase is needed in order to open the DNA to expose the nucleotide bases that are used as the template for replicating the DNA. The area of the DNA that is opened by DNA helicase is known as the replication fork because it looks very similar to a fork in the road.

Detailed explanation-5: -The replication fork is the area where DNA replication actually takes place. Once these two strands are opened and exposed, they serve as the template for DNA polymerase to add matching complementary nucleotides to the growing strand, thus replicating the DNA.