A vacuole is a membrane-bound organelle found in the cells of plants, fungi, and some protists. It serves various functions, including storing nutrients, waste products, and other substances. In plant cells, vacuoles are often large and help maintain turgor pressure, which keeps the plant upright and healthy. In addition to storage, vacuoles play a role in cellular processes such as maintaining pH balance and breaking down complex molecules. They can also contain enzymes that aid in digestion within the cell. Overall, vacuoles are essential for the proper functioning of many types of cells, particularly in the plant kingdom.