Thread: DNA replication?

Hi could anyone please supply a step by step numerical breakdown of the processes involved in DNA replication? I mean I know some processes happen at the same time, but what's the general thrust of things?

It would be really helpful if I could see something in a step 1, step 2, step 3 step 4 etc. type format.

You see the problem is I've read about and watched loads of videos about each of the individual steps, but I'm having real trouble stitching it all together. Of particular confusion is in this video here: DNA Transcription (Advanced) - YouTube it shows the DNA molecule being copied into RNA first, presumably for later transcription back into DNA?

However in this (really very good) online tutorial, http://www.wiley.com/college/pratt/0...ion/index.html it shows DNA being copied directly through a process of sem-conservative replication. So which is it? Or is it both? If so at which points do these processes occur? Also the initial video shows RNA-polymerase appearing to 'race along' the DNA molecule and unzip it to create an RNA template? But surely the RNA molecule doesn't move at all (or at least very little?) Isn't it the DNA molecule that gets fed through the RNA polymerase, a bit like film being fed through and old style cinema film camera?

I think you are maybe muddling together two very different processes. Transcription and replication are two separate things.


In general, RNA polymerase (in this case a DNA-dependent RNA polymerase) makes single-stranded RNA copies from a DNA template. The RNA molecules produced in this process, termed transcription, are known as messenger RNA's (mRNA); these are then exported from the nucleus to dock at ribosomes where they are translated into proteins. Transcription is not part of the replication process. Although there are some basic similarities with transcription, DNA replication is carried out by a far more complex collection of enzymes and occurs independently of transcription.


You could watch some of the longer videos on YouTube (Search > Filter > Duration > Long) where you'll find videos of many decent undergrad-level lectures on the topic of DNA replication.

Drew Berry: Animations of unseeable biology | Video on TED.com

Here is a link from my 441 biochem class, slides looking much better these days, it is pretty thorough

http://courses.washington.edu/bioc44...ucleotides.pdf