Biology Reference
In-Depth Information
of cell functions will be referred to as the
IDS-cell function identity hypothesis
(ICFIH). It is clear that asserting ICFIH does not entail denying the causal roles for
other cell constituents, namely, proteins, RNA, and DNA but emphasizes the
immediacy of IDSs among the four possible causes of cell functions (see Sect.
12.5
for further details).
10.3 The Triadic Structure of the Living Cell
Dissipative structures
are distinct from
covalent
and
conformational
(also called
noncovalen
t) structures in that they are “far-reaching” or “global” in contrast to
covalent and noncovalent structures whose effects are localized within one (in the
case of covalent structures) or a set of contiguous molecules in physical contact (in
the case of noncovalent structures). The “far-reaching” (or “global”) effects of
dissipative structures inside the cell can be mediated by electric field (in the case of
action potentials) or mechanical tensions (in the case of the cytoskeletons, the
dynamics of interconnected microfilaments, intermediate filaments, and
microtubules, supported by ATP or GTP hydrolysis). Ingber (1998) and his
colleagues have obtained direct experimental evidence showing that local
perturbations of a living cell under mechanical tensions can propagate throughout
the cell, which phenomenon these authors referred to as “tensegrity,” or
tensional
integrity
. Thus, Ingber's
tensegrity
belongs to the class of intracellular dissipative
structures (IDSs).
It is suggested here that dissipative structures are essential (along with covalent
and noncovalent ones) for cell
reasoning
and
computing
because their “far-
reaching” effects provide mechanisms to coordinate many physicochemical pro-
cesses occurring at different loci inside the cell, just as the “far-reaching” axons
allow the physicochemical processes occurring within individual neurons to get
coordinated and organized in the brain to effectuate human reasoning (Table
10.1
).
If these assignments are correct, the following conclusions may be drawn:
1. In agreement with Hartwell et al. (1999) and Norris et al. (1999, 2007a, b), it is
suggested here that a new category of structures (i.e., dissipative structures or
dissipatons) must be invoked before biologists can understand the workings of
the
living cell
(e.g., metabolic regulations, signal transduction, mitosis, morpho-
genesis, etc.), just as physicists had to invoke the notion of
strong force
(in
addition to
electromagnetic force
) before they could explain the stability of
atomic nuclei or quantum dots (see Sect.
4.15
) to explain size-dependent optical
properties of nanoparticles (
http://en.wikipedia.org/wiki/Quantum.dot
).
2. Reasoning process is not unique to the human brain but can be manifested by
cellular and abiotic systems meeting certain structural requirements in agree-
ment with the ideas of Wolfram (2002) and Lloyd (2006) in the field of computer
science. This conclusion seems in line with Wolfram's
Principle of Computa-
tional Equivalence,
according to which all natural and artifactual processes
