Respiratory O2 consumption is affec

Respiratory O2 consumption is affected by several factors that do not
affect the Vmax of the respiratory ETS. Among these short-term factors
are nutritional level, activity level, and behavioral shifts. They can
change respiration at the physiological level, but they do not change the potential respiration at the biochemical level. The potential respiration
is determined by the concentration of the enzyme complex NADH
dehydrogenase-lipoprotein in the inner membrane of mitochondria
(Nelson & Cox, 2005). This enzyme complex is constitutive and therefore
part of the mitochondrial machinery. This Vmax does not change
rapidly with changing external nutritional conditions, behavior, or
the amount of substrate metabolized. Indeed, it is a permanent characteristic
of the cell and as such varies along with variations in carbon,
nitrogen, protein and total biomass of the cell. However
because this Vmax is a property of organic catalysts it will vary with
the temperature, pressure, pH, and ionic strength of the surrounding
chemical and physical fields. Furthermore, because this Vmax is the
respiratory potential, it and the respiration rate will move in parallel
with these four factors.