Vacuoles:

Vacuoles are fluid-filled single membrane-bound organelles. Cells have many vacuoles in their cytoplasm.

Function and working of vacuoles:

When a plant cell matures its small vacuoles absorb water and fuse to form a single large vacuole in the center. The cell in this state becomes turgid. Many cells take in materials from the outside in the form of a food vacuole and then digest the material with the help of a lysosome. Some unicellular organisms use contractile vacuoles for the elimination of wastes from their bodies.