vacuole

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In biology, a fluid-filled, membrane-bound cavity inside a cell. It may be a reservoir for fluids that the cell will secrete to the outside, or may be filled with excretory products or essential nutrients that the cell needs to store.

Plant cells usually have a large central vacuole containing call sap (sugar and salts in solution) which serves both as a store of food and as a key factor in storing water and in maintaining turgor. Absorbing more water to make a bigger vacuole adds bulk to the plant. This expansion of cells is very important in plant growth. In amoebae (single-celled animals), vacuoles are the sites of digestion of engulfed food particles. Animal cells may only have small vacuoles, which are usually called vesicles.

Blue recalls the clear sky, the Atlantic Ocean, water, and rain. Red represents Namibia's people reflecting their heroism and desire for equal opportunity. White stands for peace and unity. Green symbolizes vegetation and agriculture. Effective date: 21 March 1990. >>