wetcw@pyuxa.UUCP (T C Wheeler) (07/23/84)
I have been following this 'time enough' argument and can see a hole in the 'not enough time' argument. You guys are assuming that the trys at combinations are taking place one after another, or in serial. Well, if you have this gigantic pot of soup in which these 'trys' are taking place, wouldn't it be more of a parallel action? Wouldn't 'biwions and biwions' (sorry Sagan) of 'trys' be occurring at once, given a whole ocean full of the stuff? Only one try a second is begging the question. Do raindrops fall once per second? No, and neither do chemical reactions occur on a serial basis. Remember the old 'magic' reaction where a liquid is turned instantly from clear to blue due to chemical reaction? This is not a serial reaction, it is parallel. I submit that the 'search' for an amino acid would have taken place in a parallel format which would have included ALL of the soup, not just one small portion of it? Now, all you guys go back to your calculators and figure out how much soup there was, then add in your time factor. In other words, given a finite amount of soup, and the amount of time the universe has been around (combinations could have been taking place even before the formation of the earth), how long would it take to hit the amino acids? I think this puts a different light on the subject. Further, once the first 'hit' is made (the first combination needed in building the acid) how much shorter or longer is the time factor in making the second 'hit' (the second combination factor needed to build the acid)? Could succeding 'trys' or 'hits' be shortened? Would the combination factors needed to put together an amino acid be a dominant reaction. That is, in many chemical reactions, there are primary or dominant reactions and secondary reactions, right? Would the formation of an amino acid have been a dominant reaction, thus subordinating other reactions? These are all just questions that have been bothering me since this subject came up. Anyone want to reply? T. C. Wheeler
lmc@denelcor.UUCP (Lyle McElhaney) (07/25/84)
I think I will try to show by example the mechanism by which chance is *not* brought to bear in a chemical (or biochecmical) reaction. I am paraphrasing Isaac Asimov in the essays I cited in my previous article. Let us examine the probability of assembling a water molecule from its constituent parts. A water molecule consists of an oxygen atom and two hydrogen atoms. If we simplify matters (I'll get into detail later), we can see that there are a number of ways in which the atoms could possibly unite to form *something*: O - H H-O-H O-H-H \ / 2 2 H 2 All other combinations are congruent with these three. The numbers are the number of possible ways that the three components could combine to produce that particular combination. In each case there are two possible ways, so using purely chance to define the ways in which these three molecules could combine, there is a 1/3 chance for each. This means (from a probabalistic point of view) that each form is equally likely, and that if 300 atoms of oxygen were combined with 600 hydrogen, there would be 100 molecules of each produced. Now, only one could be water; it is a tenet of physical chemistry that the form of a molecule is at least as important as its constituents in determining its properties. How is it, then, that when a mole of (atomic) oxygen and two moles of hydrogen are combined, we get exactly one mole of water? By the numbers we would expect 1/3 mole of water and 1/3 mole each of two other substances, but multiple experiments have shown that this doesn't happen. The reason is that the atoms have preferred modes of combining with other atoms to make up molecules. These are expressed in the structural notation of biochemistry by the number of dashs which link a given atom to its neighbors in schematic diagrams, like the ones I used above. Oxygen, for instance, has two such "bonds", while carbon has four and hydrogen one. These bonding numbers cannot be violated unless great stress is applied, and even then the molecules thus made generally break down when the force is eased. This being the case, it can be seen that there is in reality only one possible combination, the first displayed above, and therefore all H2O is indeed water. Further complications arise from the fact that physical chemistry takes place in three dimensions, and that the bonding counts are not the only forces which compel molecules to form as they do. Water, for instance has its two hydrogen atoms not exactly opposite each other, but rather they form an obtuse angle with respect to the oxygen atom in the center. Many of water's most interesting (and useful, not to say vital) characteristics stem from the asymmetry thus produced. These complications only make the du Nouey argument weaker, for rather than there being 3 possible combinations of H2O there are in actuality an infinity of possibilities, only one of which is really water. Enough. Bring on some better arguments, or quit the ring. -- Lyle McElhaney (hao,brl-bmd,nbires,csu-cs,scgvaxd)!denelcor!lmc