DNA replication is a process where strands of DNA are copied and two new daughter DNA molecules are formed. In this process, a number of enzymes and factors are used and one of them is DNA ligase. When the nucleotides are added on the template strand, there is a nick left behind between some nucleotides. These are the Okazaki fragments. To seal this nick or gap, DNA ligase is used. It catalyzes the formation of phosphodiester bond between the nucleotides of Okazaki fragments. This is how it looks like-