AP BIOLOGY

Detailed explanation-1: -The RNA primers are removed and replaced by DNA through the activity of DNA polymerase I, the other polymerase involved in replication. The nicks that remain after the primers are replaced get sealed by the enzyme DNA ligase .

Detailed explanation-2: -DNA polymerase I (pol I) processes RNA primers during lagging-strand synthesis and fills small gaps during DNA repair reactions.

Detailed explanation-3: -The physiological function of Pol I is mainly to support repair of damaged DNA, but it also contributes to connecting Okazaki fragments by deleting RNA primers and replacing the ribonucleotides with DNA.

Detailed explanation-4: -Each section begins with an RNA primer. This discontinuous synthesis results in the generation of fragments on the lagging strand called Okazaki fragments. DNA polymerase I recognizes a “nick” or break in the phosphate backbone, and then removes each RNA primer and fills the gaps with DNA.

Detailed explanation-5: -DNA polymerase I removes the RNA primer and fills in the gaps with DNA. However, DNA polymerase I cannot catalyze the reaction to remove the nicks. Another enzyme, DNA ligase, seals the nicks by forming the phosphodiester bond, thus generating a continuous sugar-phosphate backbone for the lagging strand.