Final answer:
Primase synthesizes an RNA primer which is essential for DNA polymerase to begin DNA replication.
Step-by-step explanation:
Before DNA polymerase can begin the process of DNA replication, primase must synthesize an RNA primer. This is necessary because DNA polymerases require a pre-existing 3'-OH end to which they can add nucleotides. The RNA primer created by primase provides this starting point. The primer is a short sequence of RNA nucleotides that is complementary to the DNA template strand. Once in place, DNA polymerase extends the RNA primer, adding DNA nucleotides to synthesize the new strand.