Enzymes involved in the unwinding of DNA

[horsebox]

I read a few different tutorials on DNA replication and transcription but they all said different things about what enzymes actually unwind the double helix and break the hydrogen bonds. 1 site said helicase did all the unwinding, another site said RNA polymerase does it in transcription and another side said topoimerase does the unwinding. Which is it?

DNA and RNA polymerase are the ones that synthesize the new strands so would I be right in assuming they don't do any of the preliminary tasks such as unwinding? The name helicase implies it does something to the double helix but where does topoimerase come in then?

 

[ElectricFetus]

Helicase, Topoisomerase and polymerase do very different things. Helicase exposes single strands of dna from its duplex helix form, topoisomerase does the unwinding per say rather, and polymerase does the actually synthesis of a new strand of dna.