The process of cellular respiration

Cellular respiration is mainly aerobic respiration, which is divided into three stages:

The first stage:

In the matrix of the cytoplasm, a molecule Glucose is decomposed into two molecules of pyruvate, taking off 4 [H] (activated hydrogen) at the same time; a small amount of energy is released during the decomposition of glucose, part of which is used to synthesize ATP, producing a small amount of ATP. This stage does not require the participation of oxygen and occurs in the cytoplasmic matrix.

Reaction formula: C6H12O6 enzyme → 2C3H4O3 (pyruvic acid) 4[H] small amount of energy (2ATP) (4[H] is 4NADH).

The second stage:

Pyruvate enters the matrix of the mitochondria, and all the hydrogens in the two molecules of pyruvate and 6 water molecules are taken off, and 20 of them are taken off [ H], pyruvate is oxidized and decomposed into carbon dioxide; a small amount of energy is released in this process, part of which is used to synthesize ATP, producing a small amount of energy. This stage does not require the participation of oxygen and is carried out in the mitochondrial matrix.

Reaction formula: 2C3H4O3 (pyruvate) 6H2O enzyme → 20[H] 6CO2 small amount of energy (2ATP) (20[H] is 16NADH and NADPH).

The third stage:

On the inner membrane of the mitochondria, the ***24 [H] taken off in the first two stages are combined with the 6 absorbed from the outside or produced by chloroplast photosynthesis. O2 combines to form water; a large amount of energy is released in this process, part of which is used to synthesize ATP, producing a large amount of energy. This stage requires the participation of oxygen and occurs on the inner mitochondrial membrane.

Reaction formula: 24[H] 6O2 enzyme → 12H2O A large amount of energy (34ATP)?

Extended information:

Anaerobic respiration process:

Phase 1: It is exactly the same as the first phase of aerobic respiration. carried out in the cytoplasm. Reaction formula: C6H12O6—(enzyme)→ 2 C2H5OH (alcohol) 2 CO2? A small amount of energy

Second stage: Pyruvate is decomposed into alcohol and carbon dioxide or converted into lactic acid under the catalysis of different enzymes. carried out in the cytoplasm. Reaction formula: C6H12O6—(enzyme)→ 2 C3H6O3 (lactic acid) A small amount of energy

Anaerobic fermentation process:

Alcoholic fermentation:

Pyruvate (C3H4O3) After the decarboxylation process, acetyl-CoA is not produced, but acetaldehyde is produced, and acetaldehyde accepts reducing hydrogen and is reduced to alcohol.

Lactic acid fermentation:

The respiratory process of some organisms, typically the lactic acid bacteria we are familiar with. In lactic acid fermentation, pyruvate directly generates lactic acid. This is an oxidized process and can also generate very little ATP. This process also exists in the human body. During strenuous exercise, when the muscle oxygen supply is insufficient, it will be obtained through this process. energy, and the lactic acid produced causes muscle soreness.

Reference: Baidu Encyclopedia - Aerobic Respiration