2. Define catabolism and its stages. Using the scheme below indicate common and specific stages of catabolism. Catabolism is

Catabolism is the process of breaking down complex molecules into simpler ones, releasing energy in the process. It is a part of metabolism, which also includes anabolism, the process of building up complex molecules from simpler ones.<br /><br />The stages of catabolism are as follows:<br /><br />1. **Breakdown of macromolecules**: This is the first stage of catabolism, where large macromolecules such as proteins, lipids, and carbohydrates are broken down into smaller molecules. This is done through a process called hydrolysis, where water is added to the molecule to break it down.<br />2. **Oxidation**: The second stage of catabolism is the oxidation of the smaller molecules. This is done through a process called oxidation, where electrons are removed from the molecule, releasing energy.<br />3. **Formation of Acetyl-CoA**: The third stage of catabolism is the formation of Acetyl-CoA, a molecule that is used in the next stage of metabolism, the citric acid cycle.<br />4. **Citric Acid Cycle**: The fourth stage of catabolism is the citric acid cycle, also known as the Krebs cycle. This is a series of chemical reactions that takes place in the mitochondria of cells, where Acetyl-CoA is further broken down, releasing energy.<br />5. **Electron Transport Chain**: The final stage of catabolism is the electron transport chain, where electrons are transferred from one molecule to another, releasing energy that is used to produce ATP, the main energy currency of the cell.<br /><br />In summary, catabolism is the process of breaking down complex molecules into simpler ones, releasing energy in the process. The stages of catabolism include the breakdown of macromolecules, oxidation, formation of Acetyl-CoA, the citric acid cycle, and the electron transport chain.