Shape: linear, granular or rod-shaped under light microscope

Quantity: ① Varies depending on cell type ② The minimum contains only 1 mitochondria, and the maximum contains 500,000. ③When metabolism is strong, the number of mitochondria is greater, and vice versa. ④ There are about 25 sperm cells, about 400 kidney cells, and about 1,300 mitochondria in liver cells. Most mature red blood cells have no mitochondria.

Under the electron microscope, mitochondria are closed membrane vesicle structures composed of double-layered unit membranes.

1. outer membrane (outerembrane)

2. Intima (innermembrane)

3. translocation contactsite

4.Matrix

5.elementary particle

1. Location: In the matrix of mitochondria or attached to the inner membrane of mitochondria.

2. Quantity: There are often 1 to several mtDNA molecules in a mitochondria, with an average of 5 to 10.

3. Genome structure:

4. Coding products: few. Mitochondrial tRNA, rRNA and some mitochondrial proteins.

mtDNA replication is similar to prokaryotic cells, D-loop replication

The light chain replicates later than the heavy chain

The direction of synthesis of the heavy chain is clockwise and the direction of synthesis of the light chain is counterclockwise.

Replication is not affected by the cell cycle, can transcend the stationary phase or interphase of the cell cycle, and can even be distributed throughout the cell cycle.

subtopic

1. When nuclear-encoded proteins enter mitochondria, a signal sequence is required.

2. The precursor protein remains in an unfolded state outside the mitochondria

3. The power generated by molecular motion assists the polypeptide chain to pass through the mitochondrial membrane

4. The polypeptide chain needs to be refolded within the mitochondrial matrix to form an active protein.

During mitosis and meiosis, newly synthesized mtDNA molecules are randomly distributed to daughter mitochondria, and daughter mitochondria are randomly distributed to daughter cells. Therefore, daughter cells have different proportions of mutant mtDNA molecules.

Cellular oxidation: The process in which cells, with the participation of O, decomposes various macromolecule substances to produce COz, and the released energy is stored in ATP, is also called biological oxidation. Similar to human respiration, also known as cellular respiration

While cells oxidize substances, they undergo a phosphorylation reaction of ADP, so it is also called oxidative phosphorylation.

Glucose is degraded in the cytoplasm to form pyruvate

Site of occurrence: cytoplasm

Net production of 2 ATP, 2 NADH

Under aerobic conditions, it eventually enters the mitochondria for oxidation.

Fermentation capacity under anaerobic conditions

Fermentation produces ATP under anaerobic conditions while regenerating NAD

Pyruvate enters the mitochondria and is broken down in the mitochondrial matrix to produce acetyl CoA

Site of occurrence: mitochondrial matrix

Generate 1 NADH

Acetyl CoA goes through the three-acid cycle and all its C is oxidized to CO2

produce

Site of occurrence: mitochondrial matrix

The permeability of the inner mitochondrial membrane is small, and substances with a molecular weight greater than 150 cannot pass through.

The H produced by glycolysis, acetyl-CoA, and the trisulfate cycle contains H and e-

Among them, H is captured by NADH and FADH, and pumped into the mitochondrial intermembrane cavity through the respiratory chain coenzymes.

e- is transmitted sequentially through the respiratory chain, and a free energy difference is generated during the transmission process, which is used as pump energy by coenzymes.

They finally reduce O2 to H2O, and at the same time synthesize a large amount of ATP from the grana.

Site of occurrence: mitochondrial inner membrane, grana

The respiratory chain is a series of enzyme systems that can reversibly accept and release H and e-. They are ordered in a chain on the inner mitochondrial membrane, so they are called the respiratory chain. And because they can transfer H and e-, they are also called electron transport chains.

1 respiratory chain

2 Thinking from the perspective of "free energy difference", why do cells need to undergo multiple transmissions?

3 chemiosmotic coupling hypothesis

4 grana

5 Working mechanism of ATP synthase: binding allostery