>Then why would you consider sugar to be a biochemical impurity if sand is
>not? Are you saying that a mixture of amino acids that contains sand is
>still a mixture of pure amino acids? If so, explain how. If not, then
>explain how this doesn't count as working with impure amino acids.
Sure it is still a pure mixture of amino acids. The reaction vessel is
after all made from sand, yet you don't classify that as an impurity. I
would consider an impurity something that has a chance of interfering with
a biochemical reaction. I know of no reactions that will occur between an
amino acid and quartz. Thus putting sand into a reaction vessel is no more
meaningful than performing the reaction in a glass vessel. It is simply a
straw man to divert attention away from the fact that the experiment is
being done under thoroughly unrealistic conditions for the primitive earth.
Sand is not a biochemical impurity. You do this: Take purified amino
acids and heat them to 200 degrees in a test tube (use an oil bath). Try
the reaction with pure amino acids in various concentrations and then when
you find an amino acid mix that yields a clear amber liquid, try the same
concentration of amino acids (the one that worked) with a pinch of sugar
added. Then tell me what happens when you use an impure mixture of amino
acids. This is an experiment that you can do in an hour. You don't need
to cite authorities or give references. You can do it yourself. I have
many times, with many different mixtures. I want to hear what you think of
paleobiogeochemistry when you have done the experiments yourself. There
are many chemicals, including many amino acids that are unstable at the
temperatures needed to make polymers. Unless you have glu and asp present
to melt, the other amino acids will be destroyed by the heat. Of course,
you can get the reaction to occur no matter what relative perportion of glu
and asp you have, as long as it is enough to form a melt first that will
solubilize the other amino acids. But try leaving them out, and you will
find out why they have to be there in sufficient quantity to form the
liquid for the melt. Again, these are all simple experiments you can do in
an afternoon, while you are doing your other work. No need to guess. Try
mixing all of the chemicals produced in the Miller experiment in dry form
together and heat to 200 degrees C. That will be a good test of whether it
is important to use pure amino acids in the proper ratios.
Remember, this is supposed to be easy...it happened so often that it
generated life, but without chemists or pure chemicals.
As to getting the amino acids onto the hot lava for the polymerization
reaction, no sweat. Simply boil away 100,000 to 1,000,000 liters of ocean
water to get 1 gram of amino acids, without cooling the rock below 200
degrees, and while preventing rain from washing them back into the ocean
before you have heated them to 200 degrees for long enough for
polymerization to occur, but not long enough for them to be carbonized.
But be sure they are all amino acids and no other molecules that might
start a carbonization reaction leading to tar, and that the ratio is such
that glu and asp are the predominant forms (remember...no biochemists there
to control the additions), and that the temperature reaches 200 degrees but
doesn't exceed that by enough to destroy what you have produced.
Just find me a realistic way to get pure amino acids in high enough
concentrations in the primitive ocean and we will move on.