Final answer:
Helicase is an enzyme involved in DNA replication. It separates the DNA strands at the origin of replication and helps to form replication forks. Without helicase, DNA replication cannot proceed.
Step-by-step explanation:
Helicase is an enzyme involved in DNA replication. In E. coli, helicase separates the DNA strands at the origin of replication, while in eukaryotes, helicase opens up the DNA helix. This allows for the replication forks to form and for DNA synthesis to occur. Without helicase, the DNA strands would not be properly separated, preventing replication from proceeding.