Active transport moves substances from a more dilute solution to a more concentrated solution (against a concentration gradient). This requires energy from respiration.
Active transport occurs in a range of scenarios including:
- Active transport allows mineral ions to be absorbed into plant root hairs from very dilute solutions in the soil. Plants require these ions for healthy growth.
- Active transport allows sugar molecules to be absorbed from lower concentrations in the gut into the blood which has a higher sugar concentration. These sugar moleculess are then used for cellular respiration.