Absorption Definition

Absorption, in biology, is the process of taking or assimilating substances into the cell or across the tissues by the process of diffusion or osmosis.

• Absorption of substances into a cell or tissue usually occurs through the general surface of the cell.
• The rate and process of absorption depend on a number of factors like the concentration of the substance, surface area and duration of contact, and solubility of the material.
• The substance that is taken in is termed absorbate, whereas the substance that takes in the absorbate is terms absorbent.
• Absorption takes place due to the presence of empty spaces within the molecules of the absorbent, which are then filled by the molecules of absorbate.
• The process of absorption might occur either without the application of energy (diffusion) or with the expenditure of energy (active transport).
• Absorption is an endothermic process where the heat energy of the system increases after taking in new molecules.
• In most of the cases of absorption, solid substances dissolve in the liquid phase and then are absorbed into the cell or tissue.
• Absorption is a bulk phenomenon where the absorbed material is uniformly distributed throughout the absorbent and thus affects the entire system.
• Absorption occurs in all living and non-living systems either to intake nutrients or to maintain the homeostasis or concentration of substances across a surface.
• The interactions between the absorbent and absorbate are physical and non-specific. Also, no chemical forces are involved.