AP BIOLOGY

Detailed explanation-1: -Replication in prokaryotes starts from a sequence found on the chromosome called the origin of replication-the point at which the DNA opens up. Helicase opens up the DNA double helix, resulting in the formation of the replication fork.

Detailed explanation-2: -It turns out that there are specific nucleotide sequences called origins of replication where replication begins. In E. coli, which has a single origin of replication on its one chromosome (as do most prokaryotes), it is approximately 245 base pairs long and is rich in AT sequences.

Detailed explanation-3: -The number of Ori sites varies in prokaryotes and eukaryotes. Replication starts at a single Ori site in bacteria, but in eukaryotes multiple Ori sites are used for fast copying across all chromosomes.

Detailed explanation-4: -In prokaryotic cells, there is only one point of origin of replication and eukaryotic cells have multiple points of origin.