How many ATPs are directly formed during the glycolysis cycle of by 6 molecules of glucose?
a. 24
b. 32
c. 36
d. 38

Hint: Glycolysis is derived from the Greek worlds (glucose- sweet or sugar; lysis- dissolution). It is a universal pathway in the living cells. Glycolysis cycle is often referred to as Embden-Meyerhof-Parnas pathway (EMP pathway) in honour of the biochemists who made a major contribution to the knowledge of glycolysis.

Complete answer:
Glycolysis is defined as the sequence of reaction converting glucose (or glycogen) to pyruvate or lactate, with the production of ATP.
During glycolysis, a total 4 ATPs are formed out of which 2 are consumed. So, 24 ATPs are directly formed during the glycolysis cycle of by 6 molecules of glucose.

Salient features of glycolysis

- Glycolysis takes place in the cells of the body. The enzymes of this pathway are existing in the cytosomal fragment of the cell.
- Glycolysis takes place in the absence of oxygen (anaerobic) or in the existence of oxygen (aerobic). Lactate is the end product under anaerobic condition. In the aerobic condition, pyruvate is formed, which is then oxidized to $CO_2$ and $H_2O$.
- Glycolysis is a crucial pathway for ATP synthesis in tissues lacking mitochondria, e.g. erythrocytes, cornea, lens etc.
- Glycolysis is very essential for the brain which is dependent on glucose for energy.
- Thus, the intermediates of glycolysis are functional for the synthesis of amino acids and fat.

So, the correct answer is 24.

Note: Glycogen is the storage form of glucose. The degradation of glycogen (glycogenolysis) in muscle meets the immediate fuel requirements, where the liver glycogen maintains the blood glucose level.