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particles move around randomly,then they end up evenly spaced.

MEANING - Diffusion is the passive movement of particles from an area of higher concentration to an area of lower concentration.

it happens in both liquids and gases because particles in these substances are free to move around randomly.the simplies type of diffusion is when different gases diffues through each other. this is whats happening when a smell is diffused around a room.

cell membranes are kind of clever :

they hold ur cells together but let stuff in and out aswell.

only things like glucose, amino acids, water and oxygen can go in and out of the cell.

big molecules like starch and proteins cant fit through the membrane.

just like diffusion in air, particles flow through the cell membrane from where there's a higher concentration (more of them) to where theres a lower concentration (not alot of them).

they only moving around randomly ofcourse, so they go both ways - but if theres a lot more particles on one side of the membrane, theres a net (overall) movement from that side.

3. the rate of diffusion depends on three main things:

a) distance - substances diffuse ore quickly when they haven't as far to move.

b) concentration difference (gradient) - substances diffuse faster if there's a big difference in concentration. if there are lots more particles on one side, there are more there to move across.

c.surface area - the more surface area there is available for molecules…


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