Diffusion, osmosis and active transport
- Created by: Serena_123
- Created on: 03-05-17 14:57
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- Diffusion, Osmosis and Active Transport
- Diffusion is the NET random movement of particles from an area of high concentration to an area of low concentration down a concentration gradient
- The rate of diffusion is affected by temperature, surface area and the different concentrations
- Osmosis is the diffusion of water molecules from an area of high concentration of water to an area of low concentration across a partially permeable membrane
- Hypotonic- the water concentration is higher outside the cell than in
- Isotonic - the water concentration is the same inside the cell as out
- Hypertonic - the water concentration outside the cell is lower than in
- It is important that animal cells remain in isotonic conditions and plant cells hypotonic
- Red blood cells maintain their disc like shape in isotonic
- In hypotonic, red blood cell shrivels and bursts
- In hypertonic, red blood cells shrivel up
- The plant cell wall prevents the cell from bursting but the hypotonic conditions ensure the cell stays turgid
- In hypertonic, the plant cell becomes flaccid and will eventually plasmolyse where the cell membrane comes away from the cell wall
- Osmosis is important in animals to maintain the concentration inside cells and prevent them shrivelling up or bursting
- Active transport is the movement of molecules from a low concentration to a high concentration AGAINST a concentration gradient
- Active transport requires energy from respiration
- Active transport is important in plant root hair cells to uptake mineral ions
- active transport is important in the gut in animals to uptake glucose when levels are lower in the gut than blood
- Cells that carry out a lot of active transport are adapted to have lots of mitochondria for the extra energy they need
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