What is the first step in DNA replication?

The first step in DNA replication is the unwinding of the DNA double helix. This is accomplished by the enzyme helicase, which breaks the hydrogen bonds between the complementary base pairs of the DNA, separating the two strands and creating the replication fork. Once the DNA is unwound, single-strand binding proteins (SSBs) bind to the single strands to prevent them from re-annealing. This sets the stage for the next steps of replication, where RNA primers are added, and DNA polymerase begins the synthesis of new DNA strands.