Hi guys!
Ridiculously easy question... what would be a good/concise definition for diffusion, osmosis and active transport?
Does anyone have a definition given by VCAA from past exams?
Thanks
Diffusion: The passive
net movement (down a concentration gradient) of a
solute from a region of
high solute concentration to a region of
low solute concentration.
Osmosis: Passive
net transport (again, down a concentration gradient) of a
solvent (almost always water for the purposes of VCE biology) from a region of
low solute concentration to a region of
high solute concentration. This process usually takes place across a semi-permeable membrane.
Active transport: Active (therefore requiring energy as ATP)
net transport of a
solute from a region of
low solute concentration to a region of
high solute concentration (therefore up a concentration gradient).
I've colour-coded some important bits of those definitions, because students often get confused between solvents/solutes and the like
"
Net" is highlighted as such as it is important to remember that solutions are NOT static; there is constant flow between regions. Hence, we can identify changes only as NET movements of solutes relative to solvent concentrations in regions of a solution.
Hope this helps!