Biology Reference
In-Depth Information
thermal energy to catalyze chemical reactions without violating the Second Law,
because enzymes can store thermal energy
transiently
, i.e.,
for a time shorter than t
,
the cycling (or turnover) time of enzymes. In other words, although McClare's
molecularization of the Second Law is valid, his suggested mechanism of chemical-
to-mechanical energy conversion based on resonance mechanism may suffer from
the problem of thermalization, since the resonance energy stored in electronic
excited states of most enzymes cannot last for times longer than
t
before being
dissipated into heat and hence is unlikely to be utilized by molecular machines in
living cells.
2.1.5 The Third Law of Thermodynamics and “Schro˝dinger's
Paradox”
The Third Law of Thermodynamics was developed by Walter Nernst (1864-1941)
of the University of G
˝
ttingen during the years 1906-1912 and can be stated in
several equivalent ways, including the following (
http://en.wikipedia.org/wiki/
Third_law_of_thermodynamics
)
(Atkins 2007).
The entropy of most pure substances approaches zero as the absolute temperature
approaches zero. (2.6)
If the entropy of each element in some (perfect) crystalline state be taken as zero at the
absolute zero of temperature, every substance has a finite positive entropy; but at the
absolute zero of temperature the entropy may become zero, and does so become in the
case of perfect crystalline substances. (G. N. Lewis and M. Randall 1923)
(2.7)
Statements 2.6 and 2.7 can be expressed algebraically thus:
S
0
(2.8)
where S is the entropy of a thermodynamic system. Equation
2.8
is in turn equivalent
to the Statement 2.9:
The entropy of a thermodynamic system cannot be negative. (2.9)
Statement 2.9 is particularly useful in evaluating the concept of “negative
entropy” first
introduced by Schr
€
odinger (1998) in 1944 with the following
definition:
S
¼
k log 1
ð
=
D
Þ
(2.10)
where k is the Boltzmann constant and D stands for “disorder.” Schr
˝
dinger derived
Eq.
2.10
by simply taking the negative of both sides of the entropy formula of
