Self-replicating molecules

[vid]

Could you guys refer me to some material that explain how some specific self replicating molecule "works", eg. creates copy of itself? I do have basic understanding of chemistry, but can't exactly imagine how it is possible for molecule to bind atoms in other molecule together to form copy of itself.

Thanks.

[premjan]

It is termed auto-catalysis I think. Basically there has to be some soup of ingredients and maybe some finite even if low probability that the molecule in question will assemble one or two copies of itself from the available ingredients. Then the existing molecule has to have by some fortunate chance, the right shape to catalyze the next formation of itself. This could happen if the molecule is symmetrical in the right way, is my guess. Maybe spiral molecules like DNA and RNA are like that? Another spiral will fit into or alongside the first spiral in such cases, like a jigsaw puzzle of sorts. As organic molecules get larger the probability of a few of them being self-replicating probably increases.

Self-replication is not necessarily compulsory for life, rather there has to be some set of molecules (hypercycle) that tends to replicate itself. Maybe one of the molecules replicates another and the second one replicates the first one back. Over a period of time, one of the elements of the hypercycle becomes more complex and starts to preserve complex information as DNA does. The other elements of the hypercycle turn into a supporting cast and create a metabolism such as a cell wall, etc.

[crispy]

I thought of this a couple days ago.

DNA or RNA or peptides are made out of smaller building blocks, all connected in the same way. Lets take an example: Peptides are linked by peptide linkage and forms polypeptides. There are enzymes which catalyze the formation of these bonds between peptides. And since enzymes themselves are polypeptides it is possible for these to synthesize a copy of itself (among many many other possibilities). So an enzyme which catalyses peptide bond formation is in essence, self replication. It might not make a copy of itself every time, but it has a chance to, and this is actually all it takes.

[Kharakov]

Could you guys refer me to some material that explain how some specific self replicating molecule "works", eg. creates copy of itself? I do have basic understanding of chemistry, but can't exactly imagine how it is possible for molecule to bind atoms in other molecule together to form copy of itself.

You might want to critically analyze the use of the term "self replicating" as well. The forces that caused the molecules formation in the first place are the ones responsible for the replication, not the molecule itself, even if the specific configuration of forces as the "self replicating" molecule is part of the formation of further similar configurations of force to these "self replicating" molecules.

[Kosh3]

This is what prions do, isn't it?

http://en.wikipedia.org/wiki/Prions

[camp freddie]

Prions are more 'self-organising' than self-replicating.
They don't synthesise new proteins to replicate themselves, they just adjust the conformation of similar proteins to match their own.
There's a grey area between 'adjustment' and 'synthesis' though.

On one level, pretty much any chain-reaction is self-replicating, since the energy or product of the first reaction initiates a further reaction. Polymerisation reactions are probably the easiest to understand (from a chemistry point of view).

Self-replication (as the term is generally intended) invoves fairly large systems, like DNA and all it's associated enzymes. DNA provides the instructions to make the enzymes which make DNA. However, there are lots of enzymes involved so it's quite a complex system.

I'd be really interested to read up on the state-of-the-art research for simpler self-replicating systems if anyone has any good links.