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Author Topic:   Abiogenesis - Or Better Living Through Chemistry
Rei
Member (Idle past 5210 days)
Posts: 1546
From: Iowa City, IA
Joined: 09-03-2003


Message 48 of 85 (57498)
09-24-2003 2:16 PM
Reply to: Message 46 by Bart007
09-15-2002 3:47 PM


quote:
I believe every experiment you refer to was intelligently designed and controlled to get the intended results

So, do you acknowledge that on a planet with an atmosphere like that in the experiments discussed, abiogenesis could occur? Because we're talking about whether it is a possible phenominon or not. These experiments seem to show that, in a variety of different atmospheres, it can happen. You can argue all you want that our particular early atmosphere (which is still largely unknown) hasn't been demonstrated yet. So?

BTW, most scientists don't believe that life developed in the exposed atmosphere; the current most likely accepted location is undersea thermal vents.

quote:
peptides may form easily in the presence of amoni acids, but none that are of any use to life

So, what type of hat did you pull that out of?

quote:
to make life, we need amino acids, sugars, bases, and phosphates.

Actually, to make life, you need a self-replicating chemical or cycle, base chemicals that can be utilized for the replication, and energy. Everything else (such as more efficient routes) can come later. There is no reason that the initial energy source must be sugars. If we're talking about a deep sea vent spewing hydrogen sulfide, we're looking at something that will react with water, but even more eagerly react with sedimentary compounds that contain a poorly bonded oxygen, or react to the water in the presence of catalysts. There's no reason why proteins in such an environment should need to follow a normal cycle, working through sugars for energy. They merely should need to, via hydrogen bonding, attract similar amino acids to themselves, and catalyze the reaction to bond them. Even if they only created a protein that is a fraction of its own chain, it has greatly increased its likelyhood of finishing a replication in the future.

------------------
"Illuminant light,
illuminate me."


This message is a reply to:
 Message 46 by Bart007, posted 09-15-2002 3:47 PM Bart007 has not yet responded

Replies to this message:
 Message 49 by DNAunion, posted 10-31-2003 11:58 PM Rei has not yet responded

    
Rei
Member (Idle past 5210 days)
Posts: 1546
From: Iowa City, IA
Joined: 09-03-2003


Message 55 of 85 (64168)
11-03-2003 12:51 PM
Reply to: Message 54 by DNAunion
11-03-2003 12:19 PM


Re: sadistics
First off, the Ghadiri self-replicator is just a single example; there are countless possibilities (I could equally, say, go into the SunY self-replicator, the hexanucleotide self-replicator, Eckland's RNA polymerase self replicator, etc). In reality, there are going to be millions of possible simple self-replicators, and many times more self-catylizing cycles (i.e., where no single chemical is a self-replicator, but together they encourage the creation of more of their components). However, let's just use the Ghadiri self-replicator:

RMKQLEEKVYELLSKVACLEYEVARLKKVGE (sp? I think I'm missing one...)

Just assuming that the Ghadiri peptide is randomly pieced together (just coincidentally, it is of a form that is ideally suited to be formed by abiotic peptide synthesis, but we'll ignore that), you would have odds of 4.29e41 for producing it. However, its subunits 6.655e20 - 6.655e20 times as common as the original self-replicating peptide. If the Ghadiri ligase was formed in an environment that tends to form peptides like itself, then its subunits are quite likely to occur there as well.

Furthermore, I might ask: when given partial subunits, will the replicator assemble a partial copy of itself? If so, then its odds of survival just vastly increased, because the partial copy is well on its way to becoming a full copy, or even a deformed copy that itself makes partial copies. Anything that turns the pool of amino acids more toward a self-replicating form is a "good thing", and a positive step on the way to creating life. I'm unable to find an article on this subject either confirming or denying this possibility in respect to the Ghadiri replicator, but it seems realistic. Catalyzation to produce chemicals similar to but not exactly like the original, is likely the first step in abiogenesis, because it would be far more common than forming a complete self-replicator. This catalyzation progresses into a full hypercycle, which progresses into an ur-cell.

------------------
"Illuminant light,
illuminate me."


This message is a reply to:
 Message 54 by DNAunion, posted 11-03-2003 12:19 PM DNAunion has responded

Replies to this message:
 Message 57 by DNAunion, posted 11-04-2003 12:22 AM Rei has not yet responded
 Message 58 by DNAunion, posted 11-04-2003 12:32 AM Rei has not yet responded

    
Rei
Member (Idle past 5210 days)
Posts: 1546
From: Iowa City, IA
Joined: 09-03-2003


Message 83 of 85 (72912)
12-15-2003 4:09 AM
Reply to: Message 82 by DNAunion
12-14-2003 7:55 PM


Re: sadistics
http://http://www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=13&t=25&m=47#47

------------------
"Illuminant light,
illuminate me."


This message is a reply to:
 Message 82 by DNAunion, posted 12-14-2003 7:55 PM DNAunion has responded

Replies to this message:
 Message 84 by DNAunion, posted 12-15-2003 1:46 PM Rei has not yet responded

    
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