What is the cytoplasm of the cell. Features of the structure of the cytoplasm

It is known that most living creatures consist of water in free or bound form by 70 or more percent. Where does it come from, where it is localized? It turns out that each cell in its composition has up to 80% water, and only the rest is the mass of dry matter.

And the main "water" structure is just the cytoplasm of the cell. This is a complex, heterogeneous, dynamic internal environment, with the features of the structure and the functions that we perform, and we will get acquainted further.

Protoplast

This term is used to designate the entire internal contents of any eukaryotic minute structure separated by a plasma membrane from its other "colleagues". That is, it includes the cytoplasm - the inner environment of the cell, the organoids in it, the nucleus with nucleoli and genetic material.

What organelles are located inside the cytoplasm? It:

• Ribosomes;
• Mitochondria;
• EPS;
• Golgi apparatus;
• Lysosomes;
• Cellular inclusions ;
• Vacuoles (in plants and fungi);
• The cell center;
• Plastids (in plants);
• Cilia and flagella;
• Microfilaments;
• Microtubules.

The nucleus, separated by a cariousmoma, with nucleoli and DNA molecules, also contains the cytoplasm of the cell. In the center it is in the animals, closer to the wall - in plants.

Thus, the peculiarities of the structure of the cytoplasm will largely depend on the type of cell, the organism itself, its belonging to the realm of living beings. In general, it occupies all the free space inside and performs a number of important functions.

Matrix, or hyaloplasm

The structure of the cytoplasm of a cell consists primarily of its division into parts:

• Hyaloplasma - a constant liquid part;
• Organoids;
• Inclusions are structure variables.

Matrix, or hyaloplasm, is the main internal component, which can be in two states - ash and gel.

Cytosol is a cell cytoplasm that has a more fluid aggregative character. The cytogel is the same, but in a denser, rich state of large organic molecules. The overall chemical composition and physical properties of the hyaloplasm are expressed as follows:

• Colorless, viscous colloidal substance, sufficiently thick and mucous;
• Has a clear differentiation in structural organization, but due to mobility it can easily change it;
• From the inside is represented by a cytoskeleton or microtrabecular lattice, which is formed due to protein filaments (microtubules and microfilaments);
• On the parts of this lattice and all the structural parts of the cell as a whole are located, and due to the microtubules, the Golgi apparatus and the EPS, a message occurs between them through the hyaloplasm.

Thus, the hyaloplasm is an important part that provides many functions of the cytoplasm in the cell.

Composition of the cytoplasm

If we talk about the chemical composition, the water in the cytoplasm accounts for about 70%. This is an average value, because some plants have cells in which up to 90-95% of water. The dry substance is represented by:

• Proteins;
• Carbohydrates;
• Phospholipids;
• Cholesterol and other nitrogen-containing organic compounds;
• Electrolytes (mineral salts);
• Inclusions in the form of droplets of glycogen (in animal cells) and other substances.

The general chemical reaction of the medium is alkaline or slightly alkaline. If we consider how the cytoplasm of the cell is located, then this feature should be noted. The part is collected at the edge, in the region of the plasmalemma, and is called ectoplasm. The other part is oriented closer to the karyolemma, bears the name of endoplasm.

The structure of the cytoplasm of the cell is determined by special structures - microtubules and microfilaments, so we will consider them in more detail.

Microtubules

Hollow small elongated particles up to a few micrometers in size. The diameter is from 6 to 25 nm. Because of the too meager indicators, a complete and capacious study of these structures is not yet possible, but it is assumed that their walls consist of the protein substance tubulin. This compound has a chain helically twisted molecule.

Some functions of cytoplasm in the cell are performed precisely due to the presence of microtubules. So, for example, they participate in building the cell walls of fungi and plants, some bacteria. In the cells of animals, they are much smaller. Also these structures are responsible for the movement of organoids in the cytoplasm.

Microtubules themselves are unstable, capable of quickly disintegrating and forming again, from time to time being updated.

Microfilaments

Quite important elements of the cytoplasm. They are long threads of actin (globular protein), which, intertwining with each other, form a common network - the cytoskeleton. Another name is the micro-trabecular lattice. This is a kind of peculiarity of the structure of the cytoplasm. After all, thanks to this cytoskeleton, all organoids are held together, they can communicate with each other safely, substances and molecules pass through them, and metabolism is realized.

However, it is known that the cytoplasm is an internal cell environment that is often able to change its physical data: become more fluid or viscous, change its structure (transition from sol to gel and back). In this regard, microfilaments - a dynamic, labile part that can quickly rebuild, mutate, disintegrate and form again.

Plasma Membranes

Important for the cell is the presence of well-developed and normally functioning numerous membrane structures, which also constitutes a kind of peculiarities of the structure of the cytoplasm. After all, it is through the plasma membrane barriers that the transport of molecules, nutrients and metabolic products, gases for respiration processes, and so on. This is why most organoids have these structures.

They, like a network, are located in the cytoplasm and delimit the inner contents of their hosts from each other, from the environment. Protect and protect against unwanted substances and bacteria that are a threat.

The structure of most of them is similar - the liquid-mosaic model, which treats each plasmalemma as a bioplastic of lipids, permeated with different protein molecules.

Since the functions of the cytoplasm in the cell are primarily a transport connection between all its parts, the presence of membranes in most organoids is one of the structural parts of the hyaloplasm. Complexly, all together, they perform common tasks to ensure the vital activity of the cell.

Ribosomes

Small (up to 20 nm) rounded structures, consisting of two halves - subunits. These halves can exist both together and separate for a while. The basis of the composition: rRNA (ribosomal ribonucleic acid) and protein. The main places of localization of ribosomes in the cell:

• Nucleus and nucleoli, where the formation of the subunits on the DNA molecule occurs;
• Cytoplasm - the ribosomes are finally formed into a single structure, uniting the halves;
• Membranes of the nucleus and endoplasmic reticulum - on them the ribosomes synthesize the protein and immediately send it into the organoids;
• Mitochondria and chloroplasts of plant cells themselves synthesize ribosomes inside the body and use the produced proteins, that is, in this respect they exist autonomously.

The functions of these structures consist in the synthesis and assembly of protein macromolecules, which are expended on the vital functions of the cell.

Endoplasmic reticulum and Golgi apparatus

A large network of tubules, tubes and vesicles, which forms a conducting system inside the cell and located throughout the cytoplasm, is called the endoplasmic reticulum, or reticulum. Its function corresponds to the structure - ensuring the interconnection of organoids among themselves and the transport of nutrient molecules to the organelles.

The Golgi complex, or apparatus, performs the function of accumulating the necessary substances (carbohydrates, fats, proteins) in a system of special cavities. They are restricted from cytoplasm by membranes. It is also this organelle that is the site for the synthesis of fats and carbohydrates.

Peroxisomes and lysosomes

Lysosomes are small, round structures resembling bubbles filled with liquid. They are very numerous and distributed in the cytoplasm, where they freely move inside the cell. Their main task is the dissolution of alien particles, that is, the elimination of "enemies" in the form of dead cells of cellular structures, bacteria and other molecules.

Liquid contents are saturated with enzymes, so lysosomes participate in the cleavage of macromolecules to their monomeric units.

Peroxisomes are small oval or round organelles that have a single membrane. They are filled with liquid contents, including a large number of different enzymes. Are one of the main oxygen consumers. Their functions are performed depending on the type of cell in which they are located. It is possible to synthesize myelin for the sheath of nerve fibers, and can also oxidize and neutralize toxic substances and various molecules.

Mitochondria

These structures are not for nothing called the power (power) stations of the cell. After all, it is in them that the formation of the main energy carriers - molecules of adenosine triphosphoric acid, or ATP - takes place. In appearance, they remind of beans. The membrane, which limits the mitochondria from the cytoplasm, is double. The internal structure is strongly folded to increase the ATP synthesis surface. The folds are called cristae, they contain a large number of different enzymes for the catalysis of synthesis processes.

Most of all mitochondria have muscle cells in animals and humans, since they require an increased content and energy expenditure.

The phenomenon of cyclosis

The movement of the cytoplasm in the cell is called cyclosis. It consists of several types:

• Oscillatory;
• Rotational, or circular;
• Streamed.

Any movement is necessary to provide a number of important functions of the cytoplasm: a full-fledged movement of organoids inside the hyaloplasm, a uniform exchange of nutrients, gases, energy, excretion of metabolites.

Cyclos occurs both in plant and in animal cells, without exception. If it stops, then the body dies. Therefore, this process is also an indicator of the vital activity of beings.

Thus, it can be concluded that the cytoplasm of the animal cell, plant, any eukaryotic is a very dynamic, living structure.

The difference between the cytoplasm of the animal and plant cells

Actually, there are not many differences. The overall layout of the structure, the functions performed are completely similar. However, some differences still exist. For example:

• The cytoplasm of plant cells contains more microtubules that take part in the formation of their cell walls than microfilaments. In animals, on the contrary.
• Cellular inclusions in the cytoplasm of plants are grains of starch, in animals they are drops of glycogen.
• A plant cell is characterized by the presence of such organelles that are not found in animals. This plastids, vacuole and cell wall.

In other respects, both structures are identical in composition and structure of the cytoplasm. The number of these or those elemental links may vary, but their presence is mandatory. Therefore, the importance of the cytoplasm in the cell of both plants and animals is equally great.

The role of the cytoplasm in the cell

The value of the cytoplasm in the cell is large, if not to say that it is the determining one. After all, this is the basis in which all vital structures are located, therefore it is difficult to overestimate its role. It is possible to formulate several basic points that reveal this meaning.

1. It is she who unites all the constituent parts of the cell into one integrated unified system that realizes the processes of life activity in a coherent and coherent way.
2. Due to the water contained in the water, the cytoplasm in the cell serves as a medium for numerous complex biochemical interactions and physiological transformations of substances (glycolysis, nutrition, gas exchange).
3. This is the main "capacity" for the existence of all organelles of the cell.
4. Due to microfilaments and tubules forms a cytoskeleton, binding the organoids and allowing them to move around.
5. It is in the cytoplasm that a number of biological catalysts , enzymes, are concentrated, without which no biochemical reaction occurs.

Summing up, it is necessary to say the following. The role of the cytoplasm in the cell is practically key, since it is the basis of all processes, the environment of life and the substrate for reactions.