Self and the Beginning of Life 31“9x6” b2726 Self and the Phenomenon of Life: A Biologist Examines Life from Molecules to Humanitypolysaccharides such as starch and cellulose. Please note that, in plants,
chloroplasts and mitochondria coexist in the same cell, as the latter is
needed for energy utilization.
What is as important as the visible structures is the internal envi-
ronment of the cell. Biochemical reactions take place in an aqueous
solution under a narrow range of conditions. These include the total
salt concentration (ionic strength), the hydrogen concentration (pH
or acidity), the osmotic pressure (concentration of total particles), the
temperature, and myriad other nuances. Any deviation from the optimal
and enzymes will cease functioning and the life process will be derailed.
A complex network of feedbacks and regulations is built in to safeguard
a constant and stable internal environment — not a state of equilibrium
but a steady state.^7 The overall mechanism leading to a constant internal
environment is called homeostasis.
There is also the requirement of energy supply, which in extant
life comes from the following sources: (1) electromagnetic waves (sun-
light) for photosynthetic organisms; (2) thermal energy from the Earth;
(3) exothermal energy from oxidation-reduction of inorganic molecules;
(4) intake of organic molecules, especially carbon-rich compounds;
(5) engulfment of other organisms (a shortcut to recharge).
Energy is needed to overcome the second law of thermodynamics,
which mandates that in a closed system the natural tendency is to change
from an orderly to a disorderly situation. Schrödinger was the first to
point out this paradox in living things, as the self-organization of life is in
apparent violation of the law.^8 This paradox is resolved once we recog-
nize that an organism is neither a closed nor a chemically homogenous
system. The hierarchical nature of life makes it possible to superimpose
order at a higher level on the disordering tendency of matter at a lower
level, at the expense of energy extracted from the surrounding to con-
struct the discrete structure of a living cell.
In summary, a cell, even the simplest one, is not a bag of homoge-
neous protoplasm, but a miniature metropolis complete with a city hall,
residential buildings, commercial establishments, factories, thoroughfares,