Question

Minimum production of ATP is observed in
A. Anaerobic respiration
B. Fermentation
C. Aerobic respiration
D. Same in all the above

Answer 1

Hint:
In all living things, ATP is the primary energy carrier, and it is synthesized during the cellular respiration process. ATP is synthesized by oxidizing respiratory substrates such as proteins, lipids, and carbohydrates. High-energy bonds in ATP molecules are formed because of their oxidation, which produces energy.

Complete step by step answer:
When glucose is completely oxidized during aerobic respiration, 38 molecules of ATP are formed. An aerobic respiration process comprises glycolysis, oxidative decarboxylation of pyruvate, the Krebs cycle, and oxidative phosphorylation. There are eight molecules of ATP produced by glycolysis, 24 molecules of ATP produced by the Krebs cycle, and six molecules of ATP produced by oxidative decarboxylation of pyruvate. Hence, 38 molecules of ATP are produced during the complete oxidation of one glucose molecule.

The process of fermentation involves the breakdown of carbohydrates anaerobically using an organic molecule as the electron acceptor at the end. There is no electron transport system involved. As a result of substrate-level phosphorylation, fermentation produces only two net ATP per glucose. A glycolysis without an electron transport system generates no additional ATP from protons and electrons contributed by intermediate precursor molecules.

Anaerobic respiration starts with glycolysis just like fermentation and aerobic respiration, and it produces 2 ATP from one glucose molecule. Anaerobic respiration, on the other hand, does not end with glycolysis like fermentation, instead, it produces pyruvate and finishes as aerobic respiration. As soon as acetyl coenzyme A is produced, it goes on to the citric acid cycle. There is a constant process of making electron carriers, and everything ends up in the electron transport chain. In a process called chemiosmosis, electron carriers deposit electrons at the beginning of the chain, allowing many ATPs to be produced.

Option ‘B’ is correct

Note:
Even though Fermentation and anaerobic respiration are similar and neither uses oxygen, they differ in several ways. The process of anaerobic respiration is more like aerobic respiration than fermentation.