Question

The energy­ releasing metabolic process in which substrate is oxidized without an external electron acceptor is called:

• A. Fermentation
• B. Glycolysis
• C. Photorespiration
• D. Aerobic respiration

Answer 1

The correct option is A

Fermentation

The correct option is A.

Explanation of the correct option:

1. Fermentation is an anaerobic process in which a living cell obtains its energy via breaking down glucose and other simple sugar molecules in the absence of oxygen.
2. Fermentation ultimately results in the formation of energy which is in the form of two ATP molecules which are very less than the aerobic process of cellular respiration.
3. This process takes place mainly in the yeast cells, and muscle cells during exercise to produce lactic acid.
4. During the process of permutation what about the respiratory substrate, it is only partially oxidized and there is no external electron acceptor.

Explanation of the incorrect options:

Option B:

1. In the process of glycolysis, the glucose is converted into pyruvic acid and this process takes place in the presence of oxygen.

Option C:

1. It is the process that takes place in plants.
2. In photorespiration, the light-dependent uptake of oxygen takes place along with the release of carbon dioxide.

Option D:

1. Aerobic respiration is nothing but a process of cellular respiration that occurs in the presence of oxygen and produces energy.

Final answer: The energy­ releasing metabolic process in which substrate is oxidized without an external electron acceptor is called fermentation.