That Pesky Polymerization and the Origin of Life Problem
A well-publicised paper by Claudia Huber and Günter Wächtershäuser in Science proposed a scenario for a materialistic origin of life from non-living matter. They correctly state:
The activation of amino acids and the formation of peptides under primordial conditions is one of the great riddles of the origin of life.Indeed it is. The reaction to form a peptide bond between two amino acids to form a dipeptide is:
Amino acid 1 + amino acid 2 → dipeptide + water
H2NCHRCOOH +H2NCHR′COOH → H2NCHRCONHCHR′COOH + H2O (1)
The free energy change(ΔG1) is about 20–33 kJ/mol, depending on the amino acids. The equilibrium constant for any reaction (K) is the equilibrium ratio of the concentration of products to reactants. The relationship between these quantities at any Kelvin temperature (T) is given by the standard equation:
K = exp (–ΔG/RT)
where R is the universal gas constant (= Avogadro’s number x Boltzmann’s constant k) = 8.314 J/K.mol
For reaction (1),
K1 = [H2NCHRCONHCHR′COOH][H2O]/[H2NCHRCOOH][H2NCHR′COOH]
= 0.007 at 298 K
where a compound in square brackets symbolises the concentration of that compound.
This means that if we start with a concentrated solution of 1 M (mol/l) of each amino acid, the equilibrium dipeptide concentration would be only 0.007 M. Since tripeptides have two peptide bonds, the equilibrium tripeptide concentration would be 0.0072 M or 5x10–5 M. For a non-specific polypeptide with 100 peptide bonds (101 amino acids), the equilibrium concentration would be 3.2 x 10–216 M. NB: the problem for evolutionists is even worse, because life requires not just any polymers, but highly specified ones.
I hope you're taking notes, there's going to be a test on this material. It would be best if you read the rest of "Origin of life: the polymerization problem" here.