Question

Distinguish between the following.

(a) Aerobic respiration and Anaerobic respiration

(b) Glycolysis and Fermentation

(c) Glycolysis and Citric acid cycle

Answer 1

(a)

Aerobic Respiration	Anaerobic Respiration
1. Aerobic respiration takes place in the presence of free oxygen.	1. Anaerobic respiration takes place in the absence of free oxygen.
2. The first step of this process (glycolysis) takes place in the cytoplasm while the second step (Krebs cycle) is carried out in mitochondria.	2.The complete process is carried out outside the mitochondria i.e., in the cytoplasm.
3. Glucose is completely oxidized into carbon dioxide and water.	3. Glucose is incompletely oxidized into carbon dioxide and ethyl alcohol.
4. 38 molecules of ATP are produced by the complete oxidation of one gram-mole of glucose.	4. Only 2 molecules of ATP are formed in this process.

(b)

Glycolysis	Fermentation
1. Glycolysis is a common process during aerobic and anaerobic respiration.	1. Fermentation is a type of anaerobic respiration.
2. Pyruvic acid is produced as its end product.	2. Ethanol or lactic acid is produced as its end product.

(c)

Glycolysis	Citric acid cycle (Krebs cycle)
1. It is a linear pathway.	1. It is a cyclic pathway.
2. It occurs in the cell cytoplasm.	2. It occurs in the mitochondrial matrix.
3. It occurs in both aerobic as well as in anaerobic respiration.	3. It occurs in aerobic respiration only.
4. One glucose molecule breaks down to generate 2 NADH22 and 2 ATP molecules.	4. It produces 6 NADH22, 2 FADH22, and 2 ATP molecules on the breakdown of two acetyl-CoA molecules generated after glycolysis.