ATP synthesis coupled electron transport

Definition

Target type: biologicalprocess

The transfer of electrons through a series of electron donors and acceptors, generating energy that is ultimately used for synthesis of ATP. [ISBN:0716731363]

ATP synthesis coupled electron transport, also known as oxidative phosphorylation, is a fundamental biological process that generates the majority of ATP, the primary energy currency of cells. It occurs in the mitochondria, specifically in the inner mitochondrial membrane. The process involves a series of electron transfers down an electron transport chain, releasing energy used to pump protons across the membrane, creating a proton gradient. This gradient drives the synthesis of ATP by the enzyme ATP synthase. Here's a detailed breakdown:

1. **Electron Transport Chain:** The chain consists of four protein complexes (I, II, III, and IV) embedded in the inner mitochondrial membrane. Electrons from NADH and FADH2, generated from the breakdown of carbohydrates, fats, and proteins, enter the chain at different points. As electrons move down the chain, they lose energy, which is used to pump protons from the mitochondrial matrix to the intermembrane space.

2. **Proton Gradient:** The pumping of protons creates a proton gradient across the inner mitochondrial membrane. The concentration of protons is higher in the intermembrane space than in the matrix. This gradient represents potential energy, like a dam holding back water.

3. **ATP Synthase:** ATP synthase is a complex enzyme that spans the inner mitochondrial membrane. It has two main components: F0 and F1. F0 forms a channel through which protons flow back into the matrix, driven by the proton gradient. This flow of protons rotates the F1 component, which acts like a motor to drive the synthesis of ATP from ADP and inorganic phosphate.

4. **ATP Synthesis:** The rotation of F1 causes conformational changes in the enzyme, allowing it to bind ADP and phosphate, and then catalyze their reaction to form ATP. This process is highly efficient, producing approximately 3 ATP molecules for every pair of electrons that pass through the chain.

In summary, ATP synthesis coupled electron transport is a complex but elegant process that harnesses the energy from electron transfers to create a proton gradient, which in turn drives the synthesis of ATP. This process is essential for all living organisms, providing the energy required for all cellular activities.'
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Proteins (1)

Compounds (7)