[TML] New 3d computer simulation design

[Jerry W Barrington]

On 12/5/07 8:32 PM, Bruce Johnson wrote:

> Many biological molecules have 'handedness', ie: they exist in non-
> superimposable mirror copies.  In many cases one stereoisomer has the
> desired or 'good' effect, and the other is either does not work or
> has deleterious effects.

When I 1st heard about chirality, I thought that we'd end up with planets
having each amino acid, etc, independently random on left or right.  Then
somebody pointed to some research that chemistry would likely make almost
all biological compound either left or right, the same way across the whole
biology of the planet.  Some exceptions, of course.  This would basically
produce 2 biology's in the universe, left and right, not even partially
compatible  If they are independent, there would be 2^(number of basic
compounds) [ = several to hundreds].  Leonard was talking about 4 or so.



On 12/5/07 8:32 PM, Leonard Erickson wrote:

>> Furthermore, it was apparent that while life could crop up under the
>> oddest conditions, only a certain number of types turned up. So far in
>> all the planets surveyed only four different biologies had been found.
>> Two of those, human and Adar, were "green" biologies. That is, both used
>> something that looked more or less like chlorophyll as a basic energy
>> gathering system. One was "blue" and the last was "red."
> 
>> Given that over forty planets had been found with some sort of life,
>> there should, by straight evolutionary principles, have been forty
>> different biologies. Instead there were four. Chloro A, Chloro B,
>> Blue and Red.

Well, chlorophyll a is the most common on earth, but there are at least 5
chlorophyll  variants in use. Green plants also uses at least 4 other
compounds, including orange, yellow, brown, etc, plus more for things
besides green plants.  If they bulk of the organism is composed of
compatible amino acids and such, the exact photosynthesizing compound seem
pretty irrelevant.

As for life using amino acids and proteins completely unlike on Earth,
incredibly improbable.  Amino acids have "the general formula H2NCHRCOOH,
where R is an organic substituent."  If amino acids form at all, the
available chemistry must be substantially the same as here, so the radicals
will form similarly.  That means you may end up with different proportions,
but the common amino acids here would be there too.

For example, the simplest amino acid has just a hydrogen atom as R
(glycine).  Now you know you have hydrogen available, it's there in the rest
of the acid.  So that one would *have* to be available.  Same logic applies
to several of the 20 aminos encoded by DNA.

When the character said the bugs don't use DNA, I wonder if he was being
specific, or meant any DNA analogue.