Absorption (Cambridge (CIE) O Level Biology): Revision Note

Absorption is the movement of digested food molecules from the digestive system into the blood (glucose and amino acids) and lymph (fatty acids and glycerol)

Nutrients are absorbed in the small intestine

Absorption can occur by diffusion, osmosis and active transport

Absorption is the movement of nutrients from the intestines into cells lining the digestive system and then into the blood

Assimilation is the movement of digested food molecules from the blood

The molecules pass into the cells of all tissues and organs

• Where they are used, becoming part of the cells

Water is absorbed in both the small intestine and the colon, but most absorption of water (around 80%) happens in the small intestine