Question

Which step is called gateway step/link reaction in aerobic respiration?
A.Glycolysis
B.Formation of acetyl coenzyme A
C.Citric acid formation
D.ETS terminal oxidation

Answer 1

Hint: The important thing about aerobic respiration is the amount of energy it releases. They can split glucose into two molecules of pyruvate without oxygen.

Complete answer:
Cellular respiration is a group of metabolic reactions and processes that take place in the cells of organisms to exchange chemical energy from oxygen molecules or the nutrients into adenosine triphosphate –ATP and then liberate waste products. The reactions occupied in respiration are catabolic reactions, which split large molecules into smaller ones, releasing energy for the reason that weak high-energy bonds are meticulous in molecular oxygen and are replaced by stronger bonds in the products. Respiration is one of the major ways a cell releases chemical energy to fuel cellular activity. The whole reaction occurs in a series of biochemical steps, some of which are redox reactions. Even though cellular respiration is to be precise a combustion reaction, it evidently does not resemble one when it occurs in a living cell because of the slow, forbidden release of energy from the series of reactions.

Glycolysis is the process of metabolism of glucose into two pyruvate molecules, with the net generation of two molecules of ATP and two molecules of NADH.
It is synchronized at the entry to the pathway and at the irreversible steps
Glycolysis is generally an anaerobic reaction, and in low oxygen conditions it is the one and only source of ATP.
During aerobic respiration, pyruvic acid that is formed during glycolysis enters the mitochondrial matrix. It undergoes oxidative decarboxylation to produce carbon dioxide and NADH. The product combines with sulfur-containing coenzyme A to form the compound acetyl CoA. This reaction is catalyzed by an enzyme complex known as pyruvate dehydrogenase. This step is generally known as the link reaction or gateway step as it links glycolysis with Krebs' cycle.

Hence, the correct answer is option (A)

Note: Glycolysis involves the oxidative breakdown of glucose into pyruvate with the release of some energy as ATP and NADH.