| Name | Characteristics
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| Vacuole in plant cells |
In plant cells, the vacuole is used for storing wastes. Its membrane is called the tonoplast. The content is called cell sap. The vacuoles in young cells are smaller in size and more in number. In older cells there is only one vacuole and it occupies the major part of the cell.
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Contractile Vacuole in Protozoans
Contractile vacuole
| Most protozoans in freshwater would have the contractile vacuoles. Its role is to excrete the excess water out of the cells in order to prevent the cells from bursting. If the difference in water potential between the cytoplasm and the medium fluid is greater, the more rapidly the water would enter into the cell. Then, the frequency of operation of the contractile vacuole would be higher. If the water potentials inside and outside the cell are the same, there would be no net flow of water either into the cell or out of the cell. Then, the contractile vacuole would stop working. So, the freshwater Amoeba and Paramecium can have the contractile vacuoles. But the blood parasite Entamoeba histolytica would have no contractile vacuole, because the water potential of its cytoplasm is almost the same as that of the blood.
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Food vacuole of animal cells
| Lower animal cells can use the plasma membrane to enclose the food particles and form the Food vacuole. After combining with lysosomes, lysozyme can digest the food particle inside the food vacuole. The digested material can be absorbed through the mwmbarne of the vacuole. The undigested and unabsorbed material would be left inside.
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| The waste vacuole in animal cells | After absorption, the unabsorbed material would be left inside the vacuole. Eventually, this food vacuole containing unabsorbed material would fuse with the plasma membrane. Then, the unabsorbed material would be ejected out of the cell.
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