The first (in animals) is eating and digesting food. Food is absorbed and broken down. This is done by physical breakdown (chewing and stomach churning), then chemical breakdown by enzymes and acids) The results are absorbed into the bloodstream.
The second process of is the chemical alteration of substances in the bloodstream by the liver. Many compounds needed by cells are done by this second process. Both the liver and cellular secretions can be very specific in their action This second process is where the absorbed food reaches the cells via the liver.
Examples of assimilation by plants[change | change source]
- Photosynthesis, the process whereby carbon dioxide and water are transformed into a number of organic molecules in plant cells.
- Nitrogen fixation from the soil into organic molecules by symbiotic bacteria which live in the roots of certain plants, such as Leguminaceae.