Vacuoles are membrane bound transparent organelles present in both plant and animal cells offers buoyancy to the cell. Vacuoles are filled with water containing inorganic and organic molecules, including enzymes, in solution.
In plants, cells should be strong enough to withstand climatic changes in the environment. It has to undergo stress conditions.They have to maintain tugidity in their cells. Hence large vacuoles support them to store water and maintain turgidity of the cell. Vacuoles store nutrients required by the cell. Vacuoles also store waste materials in them.
In animals, there are special organs which maintain different process like transportation, excretion and storage. Hence, vacuoles are small and many in animal cells