Answer:
Oxygen consumption is a measure of the activity of the first two stages of cellular respiration: glycolysis and the Kreb's cycle. The addition of malate stimulates the citric acid cycle and thus stimulate respiration.
Explanation:
The added malate serves a catalytic role, because it is regenerated in the later part of the citric acid cycle. With higher concentrations of oxaloacetate or malate, higher flux of acetyl CoA will be utilized into the citric acid cycle increasing the oxygen consumption much greater levels.
The inhibition of succinate oxidation by malonate is a well known phe-
nomenon. Since the oxidation of succinate to fumarate is an integral
part of the Krebs cycle of oxidations, it has been generally assumed that
the inhibitory effect of malonate upon the oxidation of any member of
the cycle is the result of the inhibition of the succinate to fumarate step. malonate inhibits oxidations in the cycle by at least two mechanisms: in addition to the inhibition resulting from a block of succinate oxidation, malonate inhibits oxidation by another mechanism that is believed to involve combination with magnesium ions.
