BIOMOLECULES AND ENZYMES

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

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 3 is the main enzyme catalysing the 5’→3’ polymerisation of DNA strand during replication. It also has 3’→5’ exonuclease activity for proofreading. Whereas DNA polymerase 1 is the main enzyme for repair, removal of primers and filling the gaps in the lagging strand.