Diffusion
Diffusion is the movement/spreading out of particles from areas of high to low concentration.
- Goes with concentration gradient
- No energy is required
- Factors
- Temperature
- Surface area Example to learn:
- Fish have gills which are covered in large numbers of fine filaments where gas pass in and out of blood
- Filaments are adapted as they
- Have massive surface area
- This membrane for short diffusion path
- Efficient blood supply to ensure Concentration Gradient is high
Osmosis
Osmosis is the movement of water molecules from a dilute solution to a concentrated solution through a partially permeable membrane
- Goes against concentration gradient
- Cytoplasm is a relatively concentrated solution so it has low concentration of water so water moves into cell by osmosis
Active Transport
Active transport moves substances from a more dilute solution to a more concentrated solution
- Against concentration gradient
- Requires energy (from respiration)