Revision Notes

3.3 Active Transport

What is Active Transport?

  • Active transport is the movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiration
Extended Only

Examples of Active Transport

  • Energy is needed because particles are being moved against a concentration gradient, in the opposite direction from which they would naturally move (by diffusion)
  • Examples of active transport include:
    • uptake of glucose by epithelial cells in the villi of the small intestine and by kidney tubules in the nephron
    • uptake of ions from soil water by root hair cells in plants


Active transport across the cell membrane, IGCSE & GCSE Biology revision notesActive transport across the cell membrane

Extended Only

How Protein Molecules Move Particles

  • Active transport works by using carrier proteins embedded in the cell membrane to pick up specific molecules and take them through the cell membrane against their concentration gradient:
    1. Substance combines with carrier protein molecule in the cell membrane
    2. Carrier transports substances across membrane using energy from respiration to give them the kinetic energy needed to change shape and move the substance through the cell membrane
    3. Substance released into cell

Author: Jenna

Jenna studied at Cardiff University before training to become a science teacher at the University of Bath specialising in Biology (although she loves teaching all three sciences at GCSE level!). Teaching is her passion, and with 10 years experience teaching across a wide range of specifications – from GCSE and A Level Biology in the UK to IGCSE and IB Biology internationally – she knows what is required to pass those Biology exams.

Join Save My Exams

Download all our Revision Notes as PDFs

Try a Free Sample of our revision notes as a printable PDF.

Join Now