One of the permanent structures of plant and animal cells are vacuoles. However, the difference in their structure and functions in these groups of living organisms is quite significant. What is a vacuole, the structure and functions of this structure will be discussed in detail in the article.
What is a vacuole?
A vacuole, the structural features and functions of which can vary significantly, always develops from the membrane vesicles of the endoplasmic reticulum and the Golgi complex. All vacuoles are single-membrane organelles. They are located only in the cells of eukaryotic organisms.
Vacuole: structure and functions (table)
Despite the common origin, these structures acquire a certain specialization in the process of ontogenesis. Where the vacuole can be located, the structure and functions of the organelle depending on the location - all these data are contained in the table.
| Type of vacuole | Location Features | Functions |
| Reserve | Located in plant cells, occupies most of the internal contents | Stock of water with minerals dissolved in it |
| Digestive | Characteristic for cells of single and multicellular animals | The implementation of the digestion process, the breakdown of organic substances |
| Contractile | Animal cells | Regulation of osmotic cell pressure |
Plant vacuoles
The vacuole, the structure and functions of which we are now considering, is characterized by very large sizes. Located in plant cells, it fills almost the entire space of the cytoplasm, from which it is separated by its own membrane - the tonoplast. This type of vacuole is a cavity filled with cell juice. It is a liquid based on water. Minerals, polysaccharides, protein monomers, and some pigments are dissolved in it. This is a kind of reservoir in which all the necessary substances are stored. They help cells successfully survive all adverse periods. In some vacuoles secondary metabolic products accumulate, for example, alkaloids, tannins, and milky juice. They perform not only storage, but also a protective function, scaring away many animals with an unpleasant astringent taste.
Contractile vacuoles
In the cells of unicellular animals there is a contractile vacuole. Its structure and functions are somewhat different. This is a pulsating bladder that controls the level of intracellular pressure and the concentration of substances. For example, amoeba and ciliates live in an aquatic environment, the concentration of salts in which is usually higher than in their cytoplasm. According to the laws of physics, water will enter the cage of animals - from an area with a higher concentration to a smaller one. As a result of such a process, the death of organisms would inevitably occur. Contractile vacuoles remove excess water with salts dissolved in it, maintaining the turgor of the cell at a constant level, being the "organ" of excretion.
Digestive vacuoles
These vacuoles are characteristic of animal organisms. In unicellular organisms, they have the appearance of vesicles into which nutrients enter and are digested. Excretion of metabolic products occurs anywhere in the cell membrane or through a specialized hole - a powder. In multicellular organisms, lysosomes are a special form of vacuole. These are single-membrane organelles containing hydrolytic enzymes. Lysosomes carry out the processes of pinot and phagocytosis, digesting not only nutrients, but also dead cells.
So, the vacuole, the structure and functions of which we have examined, is located in the cells of plant and animal organisms. Depending on the location, it can perform storage, digestive and regulatory functions.