Question

How does the difference in solute concentration across a membrane affect the rate of diffusion?

Answer 1

diffusion is the movement of molecules/ substances from regions of higher concentration to regions of lower concentration across a membrane.  diffusion is a passive process across the membrane down the concentration gradient. the gradient of concentration, the permeability of the membrane separating them, temperature and pressure are the main factors affecting the rate of diffusion.

when the concentration of the molecule is higher in the outer side of the cell, the molecule starts moving across the membrane to the inner side of the cell (cytoplasm). the movement is based on the concentration gradient across the membrane. the molecules will stop moving when the concentration of the substance is equal in either side of the membrane. no uphill transport (movement of molecules from lower concentration to higher concentration) happens in diffusion. since it is a passive process, no energy is used for the movement of the molecule. it is mainly based on the concentration gradient of the molecules across the membrane.