DNA replication is like a zipper. The woman's jacket represents the nucleus, where DNA replication occurs during interphase. It's important for DNA replication to take place so that the daugher cells will have the same genetic info. as the parent cells and so that populations can grow.
It's hot in here, I want to take off my jacket
DNA helicase is like the part of the zipper that opens and closes the jacket. It is an enzyme that "unzips" DNA by breaking the weak hydrogen bonds between the bases of the nucleotides. The chains made are called parents strands and will be used as a template to make new chains.
The zipper is stuck!
RNA primase is like rock climbing. The woman needs a grip before climbing higher like rock climbing, RNA primase adds the enzyme RNA primer onto each DNA strand as a short segment. The primer is added added the replication fork so that DNA polymerase can start adding nucleotides.
DNA polymerase is like a copy machine. This enzyme adds DNA nucleotides to the new DNA strand from the 3' end, and must pair up with complementary bases. However, it cannot add nucleotides without a template, just like a copy machine can't copy withone one either.
Just like a needle and a thread, the enzyme DNA ligase repairs/fills gaps or breaks in the DNA molecules. Most importantly, it connects Okazaki fragments.