Osmoregulation (Leaving Cert Biology): Revision Notes
📚 Revision Notes
Osmoregulation
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Osmoregulation is the maintenance of the H₂O balance and salt balance in body fluids.
- In amoeba, osmoregulation is carried out by the contractile vacuoles.
Osmoregulation in Freshwater Amoeba
- Amoeba live in freshwater environments where the concentration of water outside the cell is higher than inside the cytoplasm.
- Water enters the amoeba through osmosis.
- Amoeba must constantly get rid of excess water.
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Osmosis: the movement of water molecules from an area of high water concentration to an area of low water concentration across a semi-permeable membrane.
Process:
- Water enters due to osmosis.
- Excess water is collected into the contractile vacuole.
- Contractile vacuole swells.
- Contractile vacuole moves to the edge of the cell.
- Contractile vacuole bursts and expels water out of the cell.
- The cycle is repeated to continuously remove excess water.
