The anabolism is the synthesis of complex organic molecules from other simpler molecules with the energy provided by the phosphate bonds of the ATP and reducing power. ATP necessary may come from the catabolism of the photosynthesis or chemosynthesis.
Before entering anabolism, we will remember the different forms of nutrition that living beings have.
Classification of organisms according to their form of nutrition
Living beings need to live:
- A source of carbon, necessary to build your organic biomolecules. Depending on your carbon source, we distinguish:
- Autotrophic organisms: they take C from CO2 from the air.
- Heterotrophic organisms: they use the C of simple organic molecules .
- A source of electrons (hydrogen) to reduce molecules. Depending on where it comes from in hydrogen, we distinguish:
- Lithotrophic organisms: hydrogen comes from inorganic substances, such as H2O, H2S.
- Organotrophic organisms: hydrogen comes from organic molecules.
- A source of energy that allows endergonic reactions to take place.
- Phototrophic organisms, if they take advantage of the energy of light.
- Chemotrophic organisms, if they use chemical energy.
- An ultimate acceptor of electrons (hydrogens) that allows the former molecule to oxidize, releasing energy. They are distinguished:
- Aerobic organisms, if oxygen is the last electron acceptor.
- Anaerobic organisms, if it is another substance that accepts the electrons.
- Water, mineral salts and nitrogen to build proteins and other nitrogenous compounds.