AP BIOLOGY

Detailed explanation-1: -To form a continuous lagging strand of DNA, the RNA primers must eventually be removed from the Okazaki fragments and replaced with DNA. In E. coli, RNA primers are removed by the combined action of RNase H, an enzyme that degrades the RNA strand of RNA-DNA hybrids, and polymerase I.

Detailed explanation-2: -RNA primers are removed and replaced with DNA by DNA polymerase I. The gaps between DNA fragments are sealed by DNA ligase.

Detailed explanation-3: -DNA polymerase I: An enzyme that removes the RNA primers and replaces them with newly synthesized DNA. Lagging strand: One of the two newly synthesized DNA strands that must be synthesized in the opposite direction from 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.

Detailed explanation-5: -DNA polymerase I (pol I) processes RNA primers during lagging-strand synthesis and fills small gaps during DNA repair reactions.