AP BIOLOGY

Detailed explanation-1: -Fourth, DNA synthesis is completed through gap filling (Figure 1E-F). At the moment of replisome encounter, a single-stranded gap exists between the 3’ end of the leading strand and the downstream Okazaki fragment of the opposing fork. This gap is filled in, and the last Okazaki fragment is processed.

Detailed explanation-2: -Step 4: Termination Another exonuclease “proofreads” the newly formed DNA to check, remove and replace any errors. Another enzyme called DNA ligase joins Okazaki fragments together forming a single unified strand.

Detailed explanation-3: -Termination of DNA replication occurs when the two forks meet and fuse, creating two separate double-stranded DNA molecules. In the well-studied bacteria Escherichia coli and Bacillus subtilis, this occurs in the terminus region, which is situated diametrically opposite the origin.

Detailed explanation-4: -In eukaryotic cells, termination of replication usually occurs through the collision of the two replicative forks between two active replication origins. The location of the collision varies on the timing of origin firing.

Detailed explanation-5: -The order of enzymes in DNA replication include the following: DNA helicase, RNA primase, DNA polymerase, and finally DNA ligase. During the process of DNA replication, the double helix unwinds with the help of the enzyme DNA helicase.