Distinguish between the following:(a) Aerobic respiration and anaerobic respiration(b) Glycolysis and fermentation(c) Glycolysis and citric acid cycle.

(a) Differences between aerobic respiration and anaerobic respiration

Aerobic respiration	Anaerobic respiration
1.It takes place in the presence of oxygen.	1.it takes place in the absence of oxygen.
2.It is completed in cytoplasm and mitochondria of cells.	2.It is completed in the cytoplasm only.
3.In involves the complete oxidation of glucose into CO2 and H2O.	3.It involves the incomplete oxidation of glucose into CO2 and alcohol.
4.One molecule of glucose on complete oxidation releases 2870 kJ of energy.	4.One molecule of glucose on oxidation releases 247 kJ of energy.

(b) Difference between glycolysis and fermentation

Glycolysis	Fermentation
1. It takes place in all organisms	1. It occurs in some microorganisms and fungi.
2. Glycolysis can function in the presence or absence of O2.	2. Fermentation takes place only in absence of oxygen.

Differences between Glycolysis and citirc acid cycle. 

Glycolysis	Citric Acid Cycle (Kreb’s Cycle)
1.Enzymes for glycolysis occurs inside the cytoplasm.	1.Kreb’s cycle operates inside mitochondria because its enzymes are present in matrix.
2.Glycolysis is the first step of respiration in which glucose is completely broken down to the level of pyruvic acid.	2.Kreb’scycle is a cyclic process, which completely breaks an active acetyl group through decarboxylation and dehydr-genation.
3.The process is common in both aerobic and anaerobic modes of respiration.	3.It occurs only in aerobic mode of respiration.
4.Glycolysis yields 2 molecules of pyruvic acid.	4.It degrades pyruvic acid completely into inorganic substances (CO2 + H2O).
5.It forms two molecules of NADH and two molecules of ATP for every molecule of glucose broken down.	5.Kreb’s cycle produces four molecules of NADH2, 2 molecules of NADPH2for every two molecules or acetyl CoA oxidised by it. Two more molecules of NADH2 are liberated during conversion of pyruvic acid to Acetyl CoA.
6. No carbon dioxide is evolved in glycolysis.	6. Carbon dioxide is evolved in kreb’s cycle.