Question

Maximum usable energy per mole of glucose metabolized will be generated during:

• A. Aerobic respiration by germinating seeds
• B. Production of methanol by enteric bacteria
• C. Fermentation into ethanol by yeast
• D. Glycolysis in the skeletal muscle of a sprinter performing a hundred metre dash

Answer 1

The correct option is A Aerobic respiration by germinating seeds

The energy yield during aerobic respiration (36 ATP) is 18 times of that during anaerobic respiration (2 ATP). The energy production in the form of ATP is much less than in anaerobic process, this is because the breakdown of glucose is incomplete and the end product is not carbon dioxide and there is no oxygen as the final electron acceptor. All these factors cause less energy production in anaerobic respiration than aerobic respiration.

Fermentation by yeast producing ethanol or anaerobic bacteria producing methanol are the examples of anaerobic respiration. While, glycolysis is the only common step between aerobic and anaerobic respiration, and only 2 ATP molecules are produced during glycolysis.

Thus, aerobic respiration yields more energy than anaerobic respiration or fermenation. Hence, maximum usable energy will be generated during aerobic respiration by germinating seeds.