Active transport
Moving substances against a concentration gradient, from low to high concentration, using energy from respiration.
Last updated
Analogy
Pushing a bike up a hill. It takes effort.
In practice
Root hair cells take in mineral ions from soil even when the soil has fewer of them than the cell.
Practice
Flashcards
- What is different about active transport?It moves substances from low to high concentration and uses energy.
Interview questions
- Explain the difference between diffusion, osmosis and active transport.
- Diffusion is the spreading of particles down a concentration gradient
- Osmosis is diffusion of water through a partially permeable membrane
- Active transport moves particles against the gradient
- Active transport needs energy from respiration
Questions people ask
Why does active transport need energy?
Particles are moved against the concentration gradient, which is like pushing something uphill. They would not go that way by themselves, so the cell uses energy released by respiration to power carrier proteins in the membrane. This is why cells doing lots of active transport have many mitochondria.
Where does active transport happen in the body?
In the small intestine, active transport takes glucose from the gut into the blood when there is more glucose in the blood than in the gut. This lets the body absorb all the glucose it can. Plant root hair cells also use it to absorb mineral ions.