Vacuola: What is, function and structure

The vacuoles are intracellular organelles that constitute compartments delimited by membranes that separate them from the surrounding cytoplasm. They are widely distributed in various cell types, covering from unicellular to multicellular organisms, both in the prokaryotic and eukaryotic kingdom. These compartments are versatile, house a variety of fluids and materialsfrom water and enzymes to solids such as sugars, salts, proteins and other essential nutrients for cellular functioning.

The formation of vacuoles generally occurs by fusion of multiple membranous vesicles, which makes them dynamic and adaptable structures that can respond to cellular needs constantly changing.

The term “Vacuola” was introduced by the French biologist Félix Dujardin in 1841, who used it to describe an “empty” intracellular space observed inside a protozoan. Since then, vacuoles have been subject to intense study, especially in plants, where they perform fundamental functions in growth, development and adaptation to different environmental conditions.

• The vacuoles, generally largethey can constitute up to 90% of the total volume of a ripe cell.
• The membrane that surrounds them, known as tonepoplasto, is essential for their function.
• Its form may vary depending on the morphology and physiological conditions of the cell.
• Inside are the Vacuolar juicecomposed of water and various elements such as poisons, waste, malic acid and reserve compounds.
• Vacuolas in animal cells, called contractiles, regulate excess water.
• They usually occupy the Most of the cellular spacewith its extended membrane.
• They originate from the endoplasmic reticulum.

Vacuolas perform various essential functions in the cell, contributing significantly to their structure and metabolism:

• Fundamental for cell growth: since its size increase entails the increase in the cell as a whole. This phenomenon results in the development of a turgidity pressure, which plays a crucial role in maintaining the hydrated cell and preserving the stiffness of the tissue, crucial aspects for its functionality.
• It acts as an internal processing center: Here, the disintegration of macromolecules and the recycling of its components inside the cell is carried out. All cell organelles, such as ribosomes, mitochondria and plastids, can be deposited and degraded in vacuoles.
• Isolate toxic metabolism secondary products from the rest of the cytoplasm: Like nicotine, a harmful alkaloid for the cell if it is left in direct contact with other cell components.

In addition to these main functions, there are other structures called vacuoles, although its function differs significantly:

• Pulsatile vacuolas: For example, they are responsible for extracting excess water from the cytoplasm and expelling it abroad by active transport. This mechanism is essential to avoid cell damage caused by excessive water accumulation, which could cause cell rupture.
• Digestive vacuolas: They are specialized in the digestion of nutritional substances. Once the digestion is completed, waste products are eliminated outside the cell, thus contributing to the maintenance of its internal balance.
• Food vacuolas: They fulfill a nutritious function, forming from the cell membrane and the smooth endoplasmic reticulum. Its main function is to store and process nutrients for later use by the cell.

The vacuola is wrapped by a simple membrane known as tenaplastwhich is permeable and plays a crucial role in cell maintenance and growth. Inside, it houses a fluid substance called Vacuolar juicecomposed of water, as well as various organic and inorganic compounds, such as reserves, waste, poisons, malic acid and hydrosoluble pigments.

On some occasions, vacuoles can develop folds in their membrane, leading to temporary and mobile structures such as transovacuolar and bulbs.

• Transvacuolar strands: They are small channels that cross the inside of the vacuola, connecting different parts of the cytoplasm. Through these channels, cytosolic molecules are transported and even some organelles such as cisterns of the Golgi apparatus, mitochondria, plasti and endosomes.
• The bulbs: They are independent spherical structures that are inside the vacuola and have a diameter that varies from 1 to 22 µm. They are composed of a double membrane and include cytoplasmic material. Some researchers suggest that they could be artifacts or temporary storage compartments of the tenaplast.

Now that you know what an vacuola is and what is its function, we invite you to read this article about cellular organelles: what are, functions and examples.

If you want to read more articles similar to Vacuola: What is, function and structurewe recommend that you enter our biology category.