Botany - Cell - The Unit of Life Question with Solution | TestHub

Vacuoles: Membrane-bound space found in the cytoplasm is called vacuole. A vacuole contains water, sap, excretory product and other useless materials. The vacuole is bound by a single membrane; called tonoplast. 
The vacuole can occupy up to 90% of the volume in a plant cell. In plant cells, the tonoplast facilitates the transport of a number of ions and other materials against concentration gradient into the vacuole. Hence, their concentration is significantly higher in the vacuole than in the cytoplasm. 
In Amoeba, the vacuoles can be contractile vacuoles or food vacuoles. Contractile vacuoles helps in storing up of excretory waste, while food vacuoles helps in storing and gathering foods.