Which enzyme is responsible for connecting Okazaki fragments during DNA replication?

During DNA replication, the process involves the synthesis of new strands, which occurs continuously on one strand (the leading strand) and in short segments on the other strand (the lagging strand). These short segments synthesized on the lagging strand are known as Okazaki fragments. The enzyme that plays a crucial role in joining these fragments together is DNA ligase.

DNA ligase catalyzes the formation of phosphodiester bonds between the 3' end of one Okazaki fragment and the 5' end of the next, effectively linking the fragments to create a continuous DNA strand. This action is essential for maintaining the integrity of the newly synthesized lagging strand during DNA replication, ensuring that all segments are properly connected.

While other enzymes like helicase and topoisomerase are important for the overall process of DNA replication—helicase unwinding the DNA double helix and topoisomerase relieving the tension created ahead of the replication fork—neither directly connects Okazaki fragments. Lysozyme, meanwhile, is an enzyme that breaks down bacterial cell walls and does not have a role in DNA replication.