Vacuole

Vacuoles are organelles. They are similar built like vesicles, but include much larger area enclosed by a membrane rooms. Because of their size, they are also visible in the light microscope. They occur, for example as food vacuoles, which have been formed by phagocytosis of parts of the cell membrane.

Particularly striking is the vacuole (also central vacuole or vacuole called ). She takes in mature plant cells usually the largest volume of a cell. The membrane that separates the cytoplasm from the adjacent vacuole is called tonoplast. Inside the vacuole is a liquid, the cell sap which contains the cytosol in contrast to very little protein, and therefore is not plasmatic. Vacuoles can have the following tasks:

• Generating a blazing state of the cell by the turgor
• Hydrogen storage of proteins, organic compounds and ions, ie substances which are toxic or interfere with the metabolism could
• By storing poisonous or bitter substances they can protect themselves from being eaten by animals, fungi (eg calcium oxalate )
• By dyes are incorporated in the cell sap, plant parts can be particularly colored: blue-purple - red are often anthocyanins, which with acids red and blue with bases forming salts ( flowers of the hollyhock, Cornflower, Hydrangea ), yellow are flavones ( flowers of primroses, snapdragons )
• They also play a role in growth and movement processes by osmotic uptake of water into the vacuole
• Digestion of macromolecules (see lysosomes in animals )
• Memory function - can be found for example in the Leguminosae, in which cotyledons vacuoles with storage proteins.
• Tannins make for an antiseptic wound layer and bring the proteins of the cytoplasm to a halt ( wound closure )

The formation of vacuoles occurs in cell growth. Within the extension of the plant cell growth, the increased volume of the cell by osmotic water absorption. Since the substance of the cytoplasm but does not grow fast enough, cavities are formed, which are then separated by tonoplast from the adjacent plasma. At the end of growth, the central vacuole often occupies so much space that the cytoplasm only forms a thin layer between the plasmalemma and tonoplast. This is how the Zentralvakuole.