• Liquid-filled sac, which is the cell sap.
• A vacuole is surrounded by the tonoplast membrane.
• Young plant cells have many small vacuoles while mature plant cells have a large vacuole.
• The vacuole in animal cells is small.
• Cell sap contains water, organic acids, sugars, amino acids, enzymes, mineral salts, oxygen, carbon dioxide and metabolic by-products.