Biology Reference
In-Depth Information
which reduces uncertainty or, equivalently, increases the probability P arbitrarily
close to unity. If these conjectures are valid, the following corollaries would follow:
With appropriate spatial structures capable of utilizing free energy, there is no event that
cannot be realized in nature with a probability arbitrarily close to unity. (7.20)
Life is an inevitable consequence of some spontaneously occurring spatial structures
capable of utilizing free energy. (7.21)
Appropriate spatial structures and complementary free energy sources are necessary and
sufficient to both originate and maintain temporal hierarchies underlying all organisms.
(7.22)
We may view these statements as reflecting a principle to be called “the
Principle of the Inevitability of Life (PIL).” That is, PIL may be interpreted as
implying that, given the right initial conditions on the surface of the earth, the
repetitive operations of the laws of physics and chemistry are bound to produce life.
Nature may have overcome the problem of joint probabilities being smaller than
individual probabilities in two ways:
1. Make the simplest (or zero-order) coincidence detectors out of enzymes, whose
structures are mechanically (i.e., conformationally) deformable so that ligand
binding can affect their internal states, including storage of free energy.
2. Make first-, second-, third-order, etc., coincidence detectors by combining
two or more zero-order coincidence detectors utilizing chemically derived free
energy.
It is suggested here that these two conditions are necessary and sufficient to
evolve high-order coincidence detectors which can output signals with arbitrarily
large probabilities. The following justification may be offered for this conclusion.
Let us consider a high-order coincidence detector composed of N subunits, where N
can be as large as 50 or more (as in the case of transcriptosomes (Halle and
Meisterernst 1996) of eukaryotes, enzyme complexes that catalyze the synthesis
of RNA molecules using DNA as a template). Hans Frauenfelder and his coworkers
(Frauenfelder 1987, Frauenfelder et al. 2001; Fenimore et al. 2005) have shown
over the past several decades that proteins can exist in numerous conformational
states, that is, 3D structures of biopolymers that can be altered without breaking
or forming covalent bonds, which he referred to as “conformational
substates
.”
These conformational substates, in turn, may be closely related to what I called
“virtual conformons” in (Ji 2000, p. 38). If we assume that only one of these
conformational substates (or a virtual conformon selected out of many to be
transformed into the corresponding “real” conformon through free energy input)
can participate in detecting the coincidence event and if its probability of occur-
rence is P
i
(where i
,
N
, is the identity of the protein subunit), then the
total probability, P, of activating the high-order coincidence detector would be
the joint probability of all the zero-order coincidence detectors needed to register
the coincidence event involved:
¼
1, 2,
...
P
¼ð
P
1
Þð
P
2
Þð
P
3
Þ:::ð
P
a
Þ
(7.23)
