How does the process of DNA replication work?

DNA replication is the process by which DNA makes a copy of itself. This happens before cell division so that each daughter cell receives an identical copy of the DNA. In order for DNA replication to occur, we need the original DNA molecule, DNA nucleotides (the building blocks of DNA) , DNA polymerase (enzyme which adds the DNA nucleotides) and primers (which show the DNA where to start adding the nucleotides).The first stage of DNA replication is the unwinding of the DNA helix. Next, the hydrogen bonds that hold the DNA bases together are broken. DNA polymerase adds the DNA nucleotides to the 3' end of the primers. DNA polymerase can only make new DNA in the 5' to 3'direction. Therefore, DNA polymerase can only travel on one side of the original strand without any interruption. This original strand, which goes from 5’ to 3’, is called the leading strand. The opposite original strand, from 3’ to 5’, is called the lagging strand and is made in fragments which are later sealed by DNA ligase. Finally, the two new strands twist around one another to form a double helix.