catabolic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways resulting in the breakdown of substances, including the breakdown of carbon compounds with the liberation of energy for use by the cell or organism. [ISBN:0198547684]

Catabolic processes are a fundamental aspect of cellular metabolism, involving the breakdown of complex molecules into simpler ones, releasing energy in the process. This energy, often in the form of ATP (adenosine triphosphate), is essential for various cellular functions, including growth, repair, and movement. Here's a detailed breakdown of the process:

1. **Initiation:** Catabolism begins with the breakdown of large molecules like carbohydrates, lipids, and proteins into smaller subunits. This step typically involves enzymes that catalyze specific reactions to break down the bonds within these molecules.
2. **Breakdown of Subunits:** The smaller subunits are further broken down through a series of enzymatic reactions. For example, glucose, a simple sugar, is broken down through glycolysis, producing pyruvate. Fats are broken down into fatty acids and glycerol, while proteins are broken down into amino acids.
3. **Electron Transport Chain (ETC):** In the final stage of catabolism, electrons are transferred through a series of protein complexes embedded in the mitochondrial membrane. This process releases energy, which is used to generate a proton gradient across the membrane.
4. **ATP Synthesis:** The proton gradient drives the movement of protons back across the membrane through ATP synthase, an enzyme that uses the energy to synthesize ATP.
5. **Waste Products:** Catabolic processes generate waste products, such as carbon dioxide, water, and ammonia. These waste products are eliminated from the body.

Overall, catabolic processes are essential for life, providing the energy needed for cellular functions and the building blocks for anabolic processes, which involve the synthesis of new molecules.'
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Proteins (2)

Compounds (51)