What does primase do in DNA replication?
Primase is an enzyme that plays a crucial role in the process of DNA replication. During replication, the double helix structure of the DNA molecule is unwound and separated into two strands, forming a replication fork. One strand serves as a template for the synthesis of a new complementary strand.
Primase synthesizes short RNA primers on the template strands at the replication fork. These primers provide a starting point for the synthesis of the new DNA strands by the enzyme polymerase. Primase adds ribonucleotides (the building blocks of RNA) to the template strand in a specific order determined by the base pairing rules (A with U, and C with G).
The synthesis of RNA primers by primase is an essential step in DNA replication, as it allows polymerase to extend the primers with deoxyribonucleotides (the building blocks of DNA). Once the new DNA strands are synthesized, the RNA primers are removed and replaced with DNA by the enzyme ligase.
In summary, the role of primase in DNA replication is to synthesize short RNA primers on the template strands at the replication fork, which provide a starting point for the synthesis of the new DNA strands by polymerase.