AP BIOLOGY

Detailed explanation-1: -In prokaryotic cells, polymerase III is the major replicative polymerase, functioning in the synthesis both of the leading strand of DNA and of Okazaki fragments by the extension of RNA primers. Polymerase I then removes RNA primers and fills the gaps between Okazaki fragments.

Detailed explanation-2: -New DNA is made by enzymes called DNA polymerases, which require a template and a primer (starter) and synthesize DNA in the 5’ to 3’ direction. During DNA replication, one new strand (the leading strand) is made as a continuous piece.

Detailed explanation-3: -The main function of the third polymerase, Pol III, is duplication of the chromosomal DNA, while other DNA polymerases are involved mostly in DNA repair and translesion DNA synthesis. Together with a DNA helicase and a primase, Pol III HE participates in the replicative apparatus that acts at the replication fork.

Detailed explanation-4: -DNA polymerase I extension unwinds the DNA, exposing a primosome assembly signal (n′ pas) or single-strand initiation A (ssiA) sequence on the leading strand (5). This single-stranded sequence motif allows assembly of the primosome through recruitment and activation of the PriA protein.