Vacuole is a membrane bound organelle containing water and a mixture of enzymes, organic and the inorganic molecules. It is found in both bacteria, fungi, protists, plants and animal cells. This organelle plays the role of an osmoregulator in the living cells.
There are four types of vacuole:
- Contractile vacuoles
- Food vacuoles
- Central vacuoles
- Gas vacuoles
This is the vacuole responsible for the regulation of the water inside the cells, when water moves through the semi permeable membrane of the cell called cell membrane into the cytoplasm where is it used to regulate osmotic pressure and concentration of electrolytes in the cell. It is thereafter moved into the vacuole for expulsion, therefore giving rise to inward moment of another volume of water through the cell membrane into the cell.
Food vacuole can also be called digestion vacuole. It is commonly found in protists such as (Amoeba and Plasmodium species). It is the site of food digestion in Amoeba and haemoglobin digestion in Plasmodium species.
This type of vacuole is found only in plants cells. The plants central vacuole is larger than the vacuoles found in animals and protists. It store water and help to maintain cells turgor pressure.
This is also referred to gas vesicle. It is found in Cyanobacteria. This vacuole helps to regulate the air in the cells. Thus helping to maintain and regulate their buoyancy
SIZES AND SHAPES
Sizes of vacuoles varies from cells to cells, and their shapes depend on the volume of fluid stored in them.
Functions of the vacuole in living cells
Vacuoles functions in eliminating waste metabolites from the cells, storing food substances and in maintaining the cell rigidity.