AP BIOLOGY

Detailed explanation-1: -The ori is the place where DNA replication begins, enabling a plasmid to reproduce itself as it must to survive within cells. The replicons of plasmids are generally different from the those used to replicate the host’s chromosomal DNA, but they still rely on the host machinery to make additional copies.

Detailed explanation-2: -Eukaryotes initiate DNA replication at multiple points in the chromosome, so replication forks meet and terminate at many points in the chromosome. Because eukaryotes have linear chromosomes, DNA replication is unable to reach the very end of the chromosomes.

Detailed explanation-3: -A DNA molecule replicates to form two identical copies of itself. During the cell cycle, replication occurs at ‘S’ phase. DNA replication is a semiconservative process, in the newly formed double-stranded DNA, one strand of original DNA is retained, which acts as a template for the formation of another strand.

Detailed explanation-4: -The initiation of DNA replication occurs in two steps. First, a so-called initiator protein unwinds a short stretch of the DNA double helix. Then, a protein known as helicase attaches to and breaks apart the hydrogen bonds between the bases on the DNA strands, thereby pulling apart the two strands.