Question

Where do the following occur in a cell?

a) Glycolysis

b) Citric Acid Cycle

c) Oxidative Phosphorylation

d) Carbon Fixation

Answer 1

Answer a. Glycolysis takes place in the cytoplasm of the cell.

In this, a molecule of glucose breaks into 2 molecules of phospho glyceric acid utilising a series of enzymes, coenzyme and cofactor. It is the first step of the aerobic respiration. It leads to the over all production of 6 ATP.

Answer b. Citric acid cycle takes place in the mitochondrial matrix.

Citric acid cycle is also known as the Kreb's cycle. It helps in converting 2 molecules of Acetyl CoA into carbon dioxide and water and reduced form of coenzymes is produced. Each cycle of kreb cycle produces 12 ATP. Thus, 2 cycles leads to the production of 12 X 2= 24 ATP. It is the third step of the aerobic respiration. It comes after oxidative decarboxylation.

Answer C. Oxidative phosphorylation occurs in the mitochondrial matrix.

It occurs after the Kreb's cycle. It leads to the production of ATP through the transfer of electrons from NADH or FADH2 to O2 through a cascade of the electron carriers.

Answer d. Carbon fixation refers to the photosynthesis. It occurs in the stroma snd grana of the chloroplast. Photosynthesis is an example of an anabolic reaction, in which starch is produced at the expense of CO2,water, sunlight, enzymes and coenzymes.

Photosynthesis is a combination of the light and the dark reaction. Light reaction occurs in the grana (piled structure of the thylakoids) and dark reaction occurs in the stroma (cytoplasm of the chloroplast) of the chloroplast.