Which enzyme is responsible for joining Okazaki fragments on the lagging strand?

DNA Ligase is the enzyme responsible for joining Okazaki fragments on the lagging strand during DNA replication. When DNA is replicated, the two strands of the double helix unwind, allowing each strand to serve as a template for the synthesis of a new complementary strand. The leading strand is synthesized continuously in the direction of the replication fork, while the lagging strand is synthesized in short sections known as Okazaki fragments, which are created in the opposite direction of the fork.

Once these Okazaki fragments are synthesized, DNA Ligase catalyzes the formation of covalent bonds between the sugar and phosphate groups of adjacent fragments, effectively sealing the gaps to create a continuous strand. This action is crucial for the integrity and stability of the DNA molecule post-replication.

In contrast, DNA Polymerase I primarily functions to remove RNA primers and replace them with DNA nucleotides, but it does not join fragments. Helicase unwinds the double-stranded DNA, facilitating access for replication, and gyrase helps relieve the torsional strain that builds up ahead of the replication fork by introducing negative supercoils into the DNA. These enzymes play distinct roles in DNA replication, but it is the action of DNA Ligase that specifically addresses the joining of