0 Members and 1 Guest are viewing this topic.
I think you will find that DNA contains no H2O, but cell cytoplasm contains lots. But don't be put off by the facts, PP.
puppypower: Is there a way to experimentally test in order to prove or falsify this? Evidence so far are not supportive because life on earth is the only example we have, despite the fact that water is the most abundant substance in the Universe
Proteins do NOT fold into a specific shape with a probability even close to 1.Synthesis of a polypeptide chain does not guarantee that the chain will fold into what would be the "correct" shape of the protein as produced in a cell. A whole range of foldamers (peptides with the same sequence of amino acids, but folded differently) will be sampled. Sometimes there are one or two foldamers that are thermodynamically preferred over the others, but there will still be a distribution.Taking a protein of the "correct" shape and denaturing it (pushing it to sample more foldamers than it would in biological setting) usually ruins the shape permanently (it rarely goes back to the original shape), even if no covalent bonds are broken.In biological systems, the shape of a protein is usually templated and/or shepherded into the right conformation by many other proteins, co-factors, ions, etc., and even then there is a not-insignificant rate of misfolding. Usually the organism has ways of detecting misfolded proteins and destroying (or fixing) them, but sometimes mis-folded proteins accumulate and lead to diseases (https://en.wikipedia.org/wiki/Proteopathy [Links inactive - To make links active and clickable, login or click here to register])Let us also note that proteins are rarely static in biological systems. That proteins change conformations allows them to be "active" machines with the organism (gates open and close, enzymes "turn on" and "turn off", some of them even "walk" https://en.wikipedia.org/wiki/Kinesin [Links inactive - To make links active and clickable, login or click here to register]).
The handedness of helices in proteins is determined by the chirality of the amino acids themselves. Natural amino acids are all of the same configuration, so it is not surprising that this chirality manifests in the secondary and tertiary structures of proteins.
However, I think that mathematical models cannot apply to biological systems that easily (at least not yet, or anytime near). For instance, mathematical models cannot fully represent true biological phenomena because they don't account for the spatial factor.