vacuolák

Vacuoles are membrane-bound organelles found in eukaryotic cells. They are essentially enclosed sacs within the cytoplasm that can contain various substances, including water, ions, nutrients, and waste products. The size and function of vacuoles can vary significantly depending on the cell type and the organism. In plant cells, a large central vacuole is a prominent feature, occupying a significant portion of the cell volume. This central vacuole plays a crucial role in maintaining turgor pressure, which is the internal pressure that supports the plant cell against its cell wall. It also stores water, ions, pigments, and waste products, and can be involved in the breakdown of cellular debris.

In animal cells, vacuoles are generally smaller and more numerous, and their functions are more diverse. They can be involved in endocytosis and exocytosis, processes by which cells take in or release substances from their environment. Some specialized vacuoles in animal cells have specific roles, such as lysosomes, which contain digestive enzymes to break down waste materials and cellular debris, or phagosomes, which are formed during phagocytosis to engulf particles. Contractile vacuoles are found in some protists, particularly those living in freshwater environments, and are responsible for expelling excess water from the cell to prevent it from bursting. The fluid within a vacuole is called cell sap.