Diffusion, osmosis and active transport, the factors affecting them, and osmosis in plant and animal cells.
Diffusion
Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration (down a concentration gradient), as a result of their random motion. It needs no energy from respiration. Examples: oxygen into cells, carbon dioxide out, gas exchange in the lungs and leaves.
Rate of diffusion increases with a steeper concentration gradient, higher temperature, shorter distance, and a larger surface area.
Viewing only
This content is free to read on superexams.com and cannot be printed or downloaded.
Read the full note, free
Create a free account to read this note in full. Every free account gets 2 complete revision notes, no card needed.