Maintenance of Life
Osmosis in red blood cells.
If a red blood cell is placed in water, water enters the cell by osmosis. Because the membrane is quite weak the cell will burst as the volume and therefore the pressure in the cell increases. Red blood cells shrink when placed in concentrated solutions of sugar as water moves out of them by osmosis. This makes the cells appear wrinkled when viewed through a microscope.
This does not happen inside the body because the kidneys make sure the concentration of the blood stays about the same as the concentration of the solution inside the red blood cell.
Osmosis in plant cells
Plant cells have a strong rigid cell wall on the outside of the cell membrane. This stops the cell bursting when it absorbs water by osmosis. The increase in pressure makes the cell rigid. This is useful as plants do not have a skeleton. Instead the leaves and shoots can be supported by the pressure of water in their cells. If plant cells lose too much water by osmosis they become less rigid and eventually the cell membrane shrinks away from the cell wall.
Water entering the cell by osmosis inflates the cell and makes it rigid
Loss of water makes the cell limp and shrinks the cell membrane away from the cell wall.
- Lysis – bursting an animal cell by osmosis
- Crenation – shrinking an animal cell by osmosis
- Turgid – a plant cell fu
- Created by: night
- Created on: 08-05-14 19:31
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