What is the role of primase in DNA replication?

Primase plays a crucial role in DNA replication by synthesizing short RNA primers that are essential for the initiation of DNA synthesis. During replication, DNA polymerase can only add nucleotides to an existing strand of nucleic acid. The RNA primers created by primase provide this necessary starting point for DNA polymerase to extend and synthesize the new DNA strand.

The process begins when primase synthesizes a short segment of RNA (the primer), which is complementary to the DNA template strand. Once the RNA primer is in place, DNA polymerase can attach to the primer and begin the elongation of the new DNA strand by adding DNA nucleotides. This function is vital because, without RNA primers, DNA replication could not start, and therefore the entire process of copying the genetic material would be compromised.

The other options pertain to different functions and enzymes in the broader context of nucleic acid metabolism, such as the roles of helicases in unwinding DNA, repair mechanisms for fixing damage to the DNA, and spliceosomes in the processing of mRNA. These processes are distinct and do not involve the direct role of primase in initiating DNA synthesis.