How do they do it?

[lancehowe]

I'm a newcomer to the world of biology, and the biggest thing that has been frustrating me is enzymes. Not what they're made of or what their function is. My question is how do they know to do it? For example, how does DNA Polymerase know when it is supposed to attach itself to DNA and begin the replication process? Is it just a chemical attraction? I don't even know if its answerable at this stage, but its been bothering me so I'd thought I'd post the question.

[mith]

Hydrophobic interactions.
Electrostatic interactions.
Minimization of energy and maximization of entropy.

[biohazard]

Briefly, what comes to DNA and replication (E. coli as an example model): there are several enzymes involved in the initiation. The enzyme complex recognizes the so-called origin of replication site by its typical nucleotide sequences (here several repeated sequences). These enzymes (I think there was 9 or so of them) open up the DNA helix and denature a small region of the DNA, thus making a "nick" on the strand. Next, other enzyme components form the replication fork. Several helicases and topoisomerases are involved here. Only after this DNA polymerase III takes the main responsibility of the replication, although still many other enzymes assist.

All in all, the process of DNA replication is amazingly complex and the underlying forces dictating the initial recognition of the origin and all subsequent enzyme activities are, like Mith said above, mediated via different chemical interactions. I think even today the exact mechanisms of how the cell regulates the DNA replication to take place only once per cell cycle are still somewhat unclear.

[lancehowe]

Its amazing the complexity of events that our bodies go through every day! Thanks for the responses, the answers were exactly what I needed.