The cells of plants and animals contain a number of structures that provide their vital functions. One of them are vacuoles. Between themselves, they have a number of significant differences. From our article you will learn what vacuoles are and why they are necessary for living organisms.
Permanent Cell Structures
Vacuoles are called single-membrane organelles of plant and animal cells. Some of them are permanent structures, others arise as their functional need. Depending on the structural features, these organelles are able to store nutrients, break them down and perform a regulatory function.
Types of structures
There are three types of vacuoles. In the cells of the simplest animals are contractile and digestive. They regulate the osmotic pressure, remove undigested residues and perform a secretory function. But in plants, these are large reservoirs containing water, in which all the substances necessary for the cell are dissolved.
Plant cell vacuole
In young plant cells, these structures can occupy almost all of the internal contents. And that is easy to explain. After all, a growing body needs a lot of reserve substances for development. What are plant cell vacuoles? These are large single-membrane reservoirs with cell juice. The latter is water with dissolved carbohydrates and residues of inorganic substances. The composition of cell juice also includes a variety of metabolic products. It can be alkaloids, tannins. There are also pigments that give color to various parts of plants. Thus, the vacuole in the plant cell plays the role of a kind of "pantry".
Contractile vacuoles
The structure of vacuole, which performs a regulatory function, is completely different. Most of these structures are found in the cells of freshwater and marine protozoa. What are vacuoles that regulate turgor cells? They are pulsating vesicles around which there is a network of tubules. These are transport routes for liquids. On the tubules, excess fluid first enters from the cytoplasm into a vacuole, and from it is already discharged.
Where does excess fluid come from in the cell and why should it be removed? It's all about the laws of physics. According to them, the movement comes from an area with a higher concentration to a smaller one. As there is more salt in the environment, water begins to flow into the cell. Its surface apparatus may simply not withstand such pressure. And thanks to contractile vacuoles, the same level of osmotic pressure and equilibrium with the environment are maintained.
Digestive vacuoles
Digestive vacuoles break down complex substances into simple substances that can absorb organisms. These structures are inconsistent entities. They arise in that part of the cytoplasm where food particles are located. It can be either solid particles or liquids. A single-membrane bubble containing hydrolytic enzymes is formed around them. Depending on the nature of the contents, the medium in it varies from acidic to alkaline. These biologically active substances accelerate chemical reactions, but are not part of its products. Further, through the wall of the vacuole, food enters the cytoplasm and is absorbed by the body. Its undigested residues are secreted through the cell membrane or specialized formations.
So, in our article we examined what vacuoles are, got acquainted with their diversity. Depending on the structural features, they are capable of storing substances, splitting them or removing them from the cell and its structures.