Biology · Grades 8–11
Diffusion, osmosis and active transport · Revision sheet
Use gradients and membrane properties to choose the process.
Learn the idea
Diffusion
Random molecular motion can produce net movement down a concentration gradient.
Osmosis
Osmosis is net water movement across a selectively permeable membrane driven by a water-potential difference.
Active transport
Moving a solute against its relevant electrochemical gradient requires an energy-coupled process.
Equilibrium
Molecules continue moving even when there is no net transfer.
Explain without looking
- Why is saying water moves to where there is more salt incomplete?
- What is a selectively permeable membrane?
Further reading and review references
- openstax.org · reference 1
- www.genome.gov · reference 2
- www.genome.gov · reference 3
- www.genome.gov · reference 4
- www.genome.gov · reference 5
- www.genome.gov · reference 6
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Independent educational review required. Grade bands are approximate; these are not officially aligned curricula.