Question

two organisms are grown with the same food source. one uses aerobic respiration for energy production, and the other uses fermentation for energy production. if both produce the same amount of atp over a 24-hour period, which one had the faster metabolic rate (i.e. used more glucose)? explain your answer.

Answer 1

The organism which used fermentation for energy production has a faster metabolic rate i.e. used more glucose.

In aerobic respiration the electrons from glucose are transferred to oxygen via electron transport chain. Glucose is oxidized and reduction of oxygen and NAD⁺ to water and NADH takes place. Aeroboc respiration produces 38 ATP per glucose molecule.

On the other hand, in fermentation the reduced NADH in aerobic respiration is converted back to NAD⁺. This process produces 2 ATP per molecule of glucose.

It is evident that aerobic respiration produces much larger quantity of ATP per molecule of glucose (38 ATP) compared to fermentation process (2 ATP). In accordance to this, if both the organism are producing the same amount of ATP, it is expected that fermentaion process had a faster matabolic rate producing same amount of ATP as that of aerobic fermentation inspite of yielding only 2 ATP per glucose molecule.