Respiration is an important process that occurs in all living organisms in which oxygen is used and carbon dioxide is released from the body. The mechanism of cellular respiration involves the following mechanism.
What is Glycolysis?
Glycolysis – This is an anaerobic process that occurs in the cytoplasm of cells. Glycolysis involves partial metabolism of glucose, yielding two molecules of pyruvic acid.
What is Krebs Cycle?
Krebs Cycle – This is an aerobic process that takes place in the mitochondria of cells. Pyruvic acid produced during glycolysis gives carbon dioxide after complete oxidation.
Difference Between Glycolysis and Krebs Cycle
| Glycolysis | Krebs Cycle |
| It is the first step of respiration yielding two molecules of pyruvic acid after the partial breakdown of a glucose molecule in a set of enzymatic processes | Krebs Cycle is the second step of aerobic respiration in which pyruvate is oxidised completely into inorganic substances forming carbon dioxide |
| Occurs in all the living organisms | Occurs in aerobes |
| Occurs inside the cytoplasm | Occurs inside the mitochondria |
| No carbon dioxide evolved | Carbon dioxide evolved |
| Oxygen not required for glycolysis | Oxygen is required for Krebs Cycle |
| Four ATP molecules are produced in the glycolysis for each glucose molecule | One ATP or GTP molecule is produced by substrate-level phosphorylation in each turn of the Kreb’s cycle |
| Consumes 2 molecules of ATP for initial phosphorylation of substance molecules | Doesn’t consume ATP |
| Net gain of two molecules of ATP and two molecules of NADH gained for every molecule of glucose broken down | Each turn of the Krebs cycle yields three molecules of NADH and two molecules of FADH2 |
| Occurs as a linear sequence | Occurs as a cyclic sequence |
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