number 3 is the central vacuole and its large, membrane-bound organelles found in plant cells that act as a storage space for water and other molecules in the cell
Plant vacuole is a membrane (tonoplast) bound space which contains sap, water, excretory products and other materials (which are not useful for plants).
It occupies 90% of the volume of the plant cell.
Tonoplast, in plants facilitates transportof ion into the vacuole (against the concentration gradient) which causes higher ionic concentration in vacuole than in the cytoplasm.
Some other points:-
Amoeba have contractile vacuole for osmoregulation and excretory purposes.
Some protists develop food vacuoles by engulfing food particles.
