In specific organelles (mainly mitochondria), with the participation of O2, various macromolecular substances are decomposed to produce Co2; at the same time, the process in which the energy released by catabolism is stored in ATP is called cellular respiration (cellular respiration). respiration), also known as biological oxidation or cellular oxidation.

1. It is essentially a series of redox reactions catalyzed by enzymes in mitochondria.

2. The energy generated is stored in the high-energy phosphate bonds of ATP

3. The entire reaction process is carried out step by step, and energy is also gradually released.

4. The reaction is carried out under constant temperature (37°C) and constant pressure conditions

5. The reaction process requires the participation of H2O

1.ATP is a high-energy phosphate compound

2. During cellular respiration, the energy released can be promptly stored in the high-energy phosphate bonds of ATP through the phosphorylation of ADP as a backup.

3. When cells require energy to carry out various activities, they can be dephosphorylated and break a high-energy phosphate bond to release energy to meet the needs of the body.

The energy carried in ATP comes from the oxidation of sugars, amino acids, fatty acids, etc. The oxidation of these substances is the prerequisite for energy conversion.

From glycolysis to ATP formation is an extremely complex process, divided into three steps

(1) Glucose is decomposed into pyruvate in the cytoplasm through the glycolysis pathway

(2) NADH H enters mitochondria through shuttle mechanism

(3) Oxidative decarboxylation of pyruvate in the mitochondrial matrix generates acetyl CoA

(1) The respiratory chain and ATP synthase complex are the structural basis of oxidative phosphorylation

(2) Oxidative phosphorylation coupling

(3) Coupling mechanism-chemiosmosis hypothesis

Mitochondria are very sensitive to changes in external environmental factors, and the influence of some environmental factors can directly cause abnormal mitochondrial function. As we age, the oxidative phosphorylation capacity of mitochondria decreases.

Mitochondria contain their own unique circular DNA, but their DNA is naked, prone to mutations and rarely repaired.

Diseases with mitochondrial structural and functional defects as the main cause are often called mitochondrial diseases (mitochondrial disorders).

Abnormal mitochondrial fusion and fission or mutations in genes encoding proteins involved in mitochondrial fusion and fission may lead to disease.

When the Drp1 gene, which is involved in mitochondrial fission, is mutated, it can lead to brain development disorders, optic nerve atrophy, and other serious complications after birth.

When mitochondrial division is disrupted, some common mitochondrial dysfunctions will result, such as loss of mitochondrial membrane potential, increased ROS, and loss of mitochondrial DNA.

Mutations in the proteins Opa1 and Mfn2 that mediate cell fusion cause Kjer's disease (autosomal dominant optic atrophy) and peroneal muscular atrophy type 2A.

Basic measures for the treatment of mitochondrial diseases include