Transport in cells Edexcel GCSE Biology – by BBC bitesize Transport in cells Diffusion is the movement of particles from a high to a lower concentration. Osmosis is the diffusion of water across a membrane. Active transport moves particles from low to higher concentrations. Topic Content 0% Complete 0/9 Steps Diffusion The rate of diffusion Investigating the effect of concentration on rate of diffusion Osmosis Core practical – Investigating osmosis in potatoes Maths – Simple compound measures of rate Maths – Calculating percentage gain and loss of mass in osmosis Active transport Comparing diffusion, osmosis and active transport Previous Topic Back to Subject Next Topic