Vacuoles - Storage Bins to the Cells
Vacuoles are storage bubbles found in cells. They are found in both animal and plant cells but are much larger in plant cells. Vacuoles might store food or any variety of nutrients a cell might need to survive. They can even store waste products so the rest of the cell is protected from contamination. Eventually, those waste products would be sent out of the cell. The structure of vacuoles is fairly simple. There is a membrane that surrounds a mass of fluid. In that fluid are nutrients or waste products. Plants may also use vacuoles to store water. Those tiny water bags help to support the plant. They are closely related to objects called vesicles that are found throughout the cell.
In plant cells, the vacuoles are much larger than in animal cells. When a plant cell has stopped growing, there is usually one very large vacuole. Sometimes that vacuole can take up more than half of the cell's volume. The vacuole holds large amounts of water or food. Don't forge that vacuoles can also hold the plant waste products. Those waste products are slowly broken into small pieces that cannot hurt the cell. Vacuoles hold onto things that the cell might need, just like a backpack.
Helping with Support
Vacuoles also play an important role in plant structure. Plants use cell walls to provide support and surround cells. The size of that cell may still increase or decrease depending on how much water is present. Plant cells do not shrink because of changes in the amount of cytoplasm. Most of a plant cell's volume depends on the material in vacuoles. Those vacuoles gain and lose water depending on how much water is available to the plant. A drooping plant has lost much of its water and the vacuoles are shrinking. It still maintains its basic structure because of the cell walls. When the plant finds a new source of water, the vacuoles are refilled and the plant regains its structure.
