Becker points that life would be impossible if all reactions
would go to equilibrium. Is it possible that you could please
to site an example (using one of the characteristics of life)
which validates this statement? What is the difference between steady
state and equilibrium?
Life is in a constant state of flux because it takes a lot of energy to
maintain. A lot of energy must be constantly put in in order to grow, to construct
complex structures out of simple ones (e.g., E. coli cells out of
glucose) and even to maintain a living complex structure (e.g., muscles moving to
obtain food, proteins being broken down to amino acids and new proteins
resynthesisized). At equilibrium, no energy is being put in, being
used, because at equilibrium there is, by definition, no change in free energy
taking place (delta G = 0). At equilibrium, complex structures would
represent only a tiny percentage of the material present with the great
majority of atoms being in simple stable compounds such as CO2 and H2O.
So to maintain and expand these complex molecules that are
characteristic of life, we need a constant great input of energy. For us, this is in the form
of the chemical energy in food. For the planet as a whole it is the from
our constant bombardment with photons from the sun.
All living organisms maintain a steady state of atoms flowing in to the
system and atoms flowing out while energy is being consumed. As an
example of steady state on an organismic basis, we can consider a human being being maintained alive
even as its atoms are changing and great amounts of glucose and other energy
sourcesare being consumed and CO2 being released. At a microscopic chemical
level,we can observe a constant amount of ATP per cell in an exponentially
growing culture of E. coli, as great amounts of ATP are being produced by
respiration and great amount expended in the synthesis of proteins and nucleic acids, etc. The ATP is constant in its steady state, but its concentration bears no relation to its equilibirum concentration, with ADP + Pi, for example.