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Author Topic:   Cell membrane and Proteins
Kingdom_of_God
Inactive Member


Message 1 of 3 (78067)
01-12-2004 4:33 PM


I am not a biologist or anything, but today in school I was taught that through a mixture of gasses and a spark amino acids are formed, and then they linked together to form protein. But in my Moms college book it states that the cell needs to be LIVING in order to link together properly. So how did the amino acids form to make proteins which help make cells if the cell ALREADY needs to be LIVING to link them?
Also: Cell membranes are a 2 layer membrane of lipids, BUT lipids only form from LIVING cells.

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 Message 2 by Loudmouth, posted 01-12-2004 5:15 PM Kingdom_of_God has not replied

Loudmouth
Inactive Member


Message 2 of 3 (78072)
01-12-2004 5:15 PM
Reply to: Message 1 by Kingdom_of_God
01-12-2004 4:33 PM


Welcome to the forum!
I think you are referencing the Miller-Urey experiment that showed the formation of amino acids from simpler compounds. I don't remember if they claimed that these amino acids polymerized into a peptide (short protein) or not. Anyway, proteins are polymers whose subunits are amino acids, that is amino acids are the pearls of a pearl necklace, so to speak. Here is a general diagram:
(added in Edit: The R and H are supposed to line up with the middle Carbon (C). For some reason the darn thing won't let me slide them over.)
* R
* |
* (-)COOH----C----NH4(+)
* |
* H
The R represents the different R groups that exist in amino acids (alanine has a simple methyl group as an R group for example). The negative and positive charges on the right and left allow the amino acids to bond to each other like opposing poles on a magnet. This process results in peptide bonds (the COOH- from one amino acid binds to the NH4+ from another). This is important in that it is simple chemistry. Because of this, peptides (short proteins) can be made outside of the cell using chemistry and special lab equipment. So, no, proteins do not require some "living energy" in order to form, but it is difficult to build long chains outside of the cell. The same can be said for lipids as well, not all sources of lipid are biological.
Just a general comment. The theory of abiogenesis (the process of getting life from non-life) is still in it's infancy. Also, it is not tied to the theory of evolution. Evolution starts with the first replicating organism and describes how species were formed after life started. The two theories are not necessarily the same theory. Anyway, hope this helps.
[This message has been edited by Loudmouth, 01-12-2004]
[This message has been edited by Loudmouth, 01-12-2004]
[This message has been edited by Loudmouth, 01-12-2004]

This message is a reply to:
 Message 1 by Kingdom_of_God, posted 01-12-2004 4:33 PM Kingdom_of_God has not replied

Adminnemooseus
Administrator
Posts: 3974
Joined: 09-26-2002


Message 3 of 3 (78476)
01-14-2004 5:40 PM


Thread copied to the Cell membrane and Proteins thread in the Origin of Life forum, this copy of the thread has been closed.

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