Active Transport (SQA National 5 Biology): Revision Note

The process of active transport

• Active transport can be defined as:

the movement of molecules and ions across cell membranes from a region of lower concentration to a region of higher concentration, using energy

• Active transport moves substances against a concentration gradient; this process is dependent on:

  • energy from respiration

  • specific membrane proteins embedded in the cell membrane

• Examples of active transport in living organisms include:

  • uptake of mineral ions from the soil by plant roots

  • absorption of some nutrients from the small intestine during digestion