Assertion: Glycolysis is the first step of respiration in which glucose completely breaks into `CO_(2)" and "H_(2)0`.
Reason: In this process. there is net gain of twenty four molecules of ATP.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false.

Answer

D

Explanation

Glycolysis is the process of breakdown of glucose or similar hexose sugar into two molecules of pyruvic acid through a series of enzyme mediațed reactions, releasing energy (ATP) and reducing power `(NADH_(2))`. It is the first step of respiration, which occurs inside the cytoplasm and is independent of `O_(2)`. In glycolysis, two molecules of ATP are consumed during double phosphorylation of glucose to form fructose 1, 6 diphosphate. Four molecules of ATP are produced in the conversion of 1, 3-diphosphoglycerate to 3-phosphogłycerate and phosphenol pyruvate to pyruvate whereas, two molecules of `NADH_(2)` are formed during oxidation of glyceraldehyde 3-phosphate to 1, 3-diphosphoglycerate. Since, each NADH is equivalent to 3 ATP, so net gain in glycolysis is 8 ATP.