Question

In anaerobic respiration, from one glucose molecule how many net ATP molecules are formed?

• A. 2
• B. 8
• C. 6
• D. 4

Answer 1

The correct option is A 2

• The steps of glycolysis remain the same till the formation of pyruvate in both aerobic and anaerobic modes of respiration. After pyruvate formation, depending on the availability of oxygen the pyruvate will have different fates in different organisms.
• In animals, where there is sufficient oxygen supply pyruvate enters the mitochondria and is completely oxidized to carbon dioxide. In the absence of oxygen, it enters the anaerobic respiration where it is converted to lactate.
• So, Under aerobic conditions, the net formation of ATP until the formation of pyruvate is 2 ATP + (1 NADH = 3 ATP) = 5 ATP. However, under anaerobic conditions, the NADH is not converted to ATP; therefore, the net production of ATP is only 2 ATP.