Diffusion, Osmosis, Active Transport
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(Credits to Mustafa Asif)
Notes
Diffusion: movement of molecules, from a region of high concentration to a region of low concentration.
- Oxygen diffuses into cells, and the waste carbon dioxide diffuses out.
Osmosis: movement of water molecules, across a partially permeable membrane, from a region of high concentration of water to a low concentration of water molecules.
- It allows plants to take in water through their roots.
- It is used in kidney dialysis machines to filter the blood.
Semi-permeable membrane
- Small molecules, such as water can pass through the small holes in the membrane…
- But larger molecules like sugar cannot pass through the membrane.
Questions
A and B are salt solutions. A has a concentration of 2 g/cm3 and B has a concentration of 3 g/cm3
a) Describe solutions A and B using the terms ‘hypotonic’, ‘hypertonic’ or ‘isotonic’.
Solution A is hypotonic relative to B.
or solution B is hypertonic relative to A
b) Describe solutions A and B in terms of water potential
Solution A has a higher water potential than solution B
or Solution B has a lower water potential than solution A
c) Describe solutions A and B in terms of concentration
Solution A is less concentrated/more dilute than solution B
Solution B is more concentrated/less dilute than solution A