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Characteristics of the movement of the cytoplasm. The cytoplasm of a living cell

Hyaloplasm (cytoplasm matrix) is a transparent colloidal solution of organic and inorganic
connections. Of the inorganic compounds in the hyaloplasm, water predominates (from 50 to 90%),
there are Ca2+, K+ cations, anions of carbonic and phosphoric acids, dissolved oxygen,
carbon dioxide and other gases. Organic compounds are proteins, amino acids,
lipids, carbohydrates, different types of RNA, individual nucleotides. In the cytoplasm there are ground substance, organelles and inclusions. The main substance of the cytoplasm is hyaloplasm fills the space between the plasmalemma, nuclear membrane and other intracellular structures. The main substance of the cytoplasm forms the true internal environment of the cell, which unites all intracellular structures and provides interaction with each other. The fulfillment by the matrix of the unifying, as well as the framework function, can be associated with the help of a super-powerful electron microscope of the microtrabecular network formed by thin fibrils. Also functionally, the cytoplasmic matrix is the site of intracellular metabolism. Through the hyaloplasm, a significant amount of intracellular movements of substances and structures is carried out. Hyaloplasm should be considered as a complex colloidal system capable of changing from liquid to gel state.

Hyaloplasm functions:
1. It is an internal environment in which many chemical processes of energy
and plastic exchange, and in particular:
- processes of oxygen-free energy metabolism with the formation of a small amount
ATP;
- processes of protein synthesis on ribosomes with the participation of mRNA, tRNA.
2. It unites all cellular structures and provides interaction between them.
The cytoplasm of a living cell is characterized by the constant movement of its colloidal particles and other
components (cyclosis). Cyclose provides the transport of substances and the movement of organelles
(for example, the movement of chloroplasts, digestive vacuoles), optimization of metabolic processes
substances, removal of metabolic products from the cell.
Organelles are permanent specialized components of the cytoplasm that have
a certain structure and perform certain functions in the cell.

7. General purpose organelles. Their structure and functions .

General purpose organelles are divided into membrane And non-membrane. Membrane, in turn, are divided into single membrane And two-membrane.
TO single membrane include:

Endoplasmic reticulum (EPR)). It is a system of membranes that form tanks and channels, connected to each other and limiting a single internal space - EPR cavities. There are two types of EPR: rough containing ribosomes on its surface smooth, whose membranes do not carry ribosomes.
Functions: divides the cytoplasm of the cell into isolated compartments, thereby providing a spatial delimitation from each other of many different reactions running in parallel. Carries out the synthesis and breakdown of carbohydrates and lipids (smooth ER) and provides protein synthesis (rough ER), accumulates in channels and cavities, and then transports biosynthesis products to cell organelles.

Golgi apparatus. An organoid usually located near the cell nucleus (often near the cell center in animal cells). It is a stack of flattened tanks with widened edges, consists of 4-6 tanks. The number of Golgi stacks in a cell ranges from one to several hundred.
The most important function of the Golgi complex is the removal of various secrets (enzymes, hormones) from the cell, therefore it is well developed in secretory cells. Here is the synthesis of complex carbohydrates from simple sugars, the maturation of proteins, the formation of lysosomes.

Lysosomes. The smallest single-membrane cell organelles, which are vesicles with a diameter of 0.2-0.8 microns, containing up to 60 hydrolytic enzymes. Lysosomes are formed in the Golgi apparatus. The breakdown of substances with the help of enzymes is called lysis, hence the name of the organoid.
There are: primary secondary lysosomes - lysosomes formed as a result of the fusion of primary lysosomes with pinocytic or phagocytic vacuoles; digestion and lysis of substances entering the cell occur in them (therefore, they are often called digestive vacuoles):
Sometimes, with the participation of lysosomes, the cell self-destructs. This process is called autolysis.

Vacuoles- large membranous vesicles or cavities in the cytoplasm filled with cell sap. Vacuoles are formed in the cells of plants and fungi from vesicular extensions of the endoplasmic reticulum or from the vesicles of the Golgi complex. vacuoles absorb excess water and then bring it out through contractions.

To double membrane organelles include:

plastids - plastids- organelles characteristic only for plant cells and found in all living cells of green plants. The inner membrane of the chloroplast forms invaginations into the stroma - thylakoids. Leucoplasts- small colorless plastids of various shapes are mainly found in the cells of organs hidden from sunlight (roots, rhizomes, tubers, seeds). They carry out secondary synthesis and accumulation of reserve nutrients.

Mitochondria are integral components of all eukaryotic cells. 0.5 µm thick and up to 7-10 µm long. Mitochondria are limited by two membranes - outer and inner. The outer membrane separates it from the hyaloplasm. The inner membrane forms many protrusions inside the mitochondria - the so-called cristae. Enzymes that participate in oxygen respiration are located on the membrane of the cristae or inside it. The internal content of the mitochondria (matrix) limited by it is close in composition to the cytoplasm. The matrix contains various proteins, including enzymes, DNA (circular molecule), all types of RNA, amino acids, ribosomes, and a number of vitamins. DNA provides some genetic autonomy for mitochondria, although in general their work is coordinated by nuclear DNA. Mitochondria are the powerhouse of the cell.

Non-membrane organelles:

Cell center. In the cells of most animals, as well as some fungi, algae, mosses and ferns, there are centrioles. They are usually located in the center of the cell, which determined their name. Centrioles are hollow cylinders no more than 0.5 µm long. They are arranged in pairs perpendicular to each other. Each centriole is built from nine triplets of microtubules. The main function of centrioles is the organization of microtubules of the spindle of cell division.

Ribosomes- these are the smallest spherical granules, which are the site of protein synthesis from amino acids. They are found in the cells of all organisms. 2 subunits- large and small, formed from
ribosomal RNA molecules and proteins.

cytoskeleton-Elements of the cytoskeleton, closely associated with the outer cytoplasmic membrane and the nuclear membrane, form complex weaves in the cytoplasm. The cytoskeleton is formed microtubules And microfilaments, determines the shape of the cell, participates in its movements, in the division and movements of the cell itself, in the intracellular transport of organelles and individual compounds.

8. Organelles for special purposes. Their structure and functions.
Special-purpose organelles are present in cells specialized for a specific function, but can also be found in small numbers in other cell types. They include, for example, microvilli of the absorptive surface of the intestinal epithelial cell, cilia of the epithelium of the trachea and bronchi, synaptic vesicles, transporting carriers of nervous excitation from one nerve cell to another or a cell of the working organ, myofibrils on which muscle contraction depends.

The cytoplasmic, or cellular, membrane (plasmalemma) is a biological membrane that surrounds the protoplasm (cytoplasm) of a living cell. The structure is based on a double layer of lipids - water-insoluble molecules that have polar "heads" and long non-polar "tails" represented by fatty acid chains; most of all, the membranes contain phospholipids, in the heads of which there are residues of phosphoric acid.

The tails of lipid molecules face each other, the polar heads look outward, forming a hydrophilic surface. Charged heads are attached to proteins called peripheral membrane proteins. Other protein molecules can be embedded in the lipid layer by interacting with their non-polar tails. Some of the proteins penetrate the membrane through, forming channels or pores. In some cells, the membrane is the only structure that serves as a membrane; in other cells, there is an additional membrane on top of the membrane (for example, the cellulose membrane in plant cells). Animal cells outside the membrane are covered with glycocalyx - a thin layer consisting of proteins and polysaccharides.

The cell membrane performs many important functions on which the vital activity of cells depends. One of them is the formation of a barrier between the internal contents of the cell and the external environment. Along with this, the membrane provides for the exchange of substances between the cytoplasm and the external environment, from which water, ions, inorganic and organic molecules enter the cell through the membrane. Products formed in the cell (metabolic products and substances synthesized in the cell) are excreted into the external environment through the membrane.

Thus, substances are transported through the membrane. Large molecules of biopolymers enter through the membrane due to phagocytosis, a phenomenon first described by I.I. Mechnikov. The process of capture and absorption of liquid droplets occurs by pinocytosis. The receptor function of the membrane plays an important role in the life of the cell. There are a large number of receptors in membranes - special proteins, the role of which is to transmit signals from the outside to the inside of the cell.

The cell nucleus is a part of the cell with a diameter of 3-10 microns surrounded by a membrane consisting of two membranes. Between the outer and inner membranes there is a narrow space (30 nm) filled with a semi-liquid substance. The nuclear membrane has the same structure as the plasma membrane. The nuclear membrane has many pores through which the process of metabolism between the nucleus and the cytoplasm takes place. Under the nuclear membrane is the nuclear juice (karyoplasm), which contains the nucleoli and chromosomes.

The nucleoli are round bodies with a diameter of 1 micron to several microns. There may be several nucleoli in the nucleus. The nucleoli are composed of RNA and protein. Nucleoli are formed on certain parts of the chromosomes; they synthesize ribosomal RNA (rRNA). In the nucleolus, the formation of large and small subunits of ribosomes occurs. Nucleoli are visible only in non-dividing cells.

Chromosomes (gr. chroma - paint and soma - body) were so named in connection with the ability to intense staining - the most important organelle of the nucleus, containing DNA in combination with the main protein - histone. This complex makes up about 90% of the substance of the chromosomes.

Chromosomes can be tens or hundreds of times longer than the diameter of the nucleus. In interphase (the period between divisions), chromosomes are visible only under an electron microscope and are long thin threads called chromatin (despiralized state of chromosomes). During this period, the process of doubling (reduplication) of chromosomes takes place; at the end of interphase, each chromosome consists of two chromatids. Each chromosome has a primary constriction, on which the centromere is located; The constriction divides the chromosome into two arms of the same or different lengths. The centromere serves as the site of attachment of the fission spindle filament. The nucleolar chromosomes also have a secondary constriction where the nucleolus is formed.

The function of chromosomes is to control all the life processes of the cell. Chromosomes are carriers of genes, that is, carriers of genetic information. Hereditary information is transmitted by replication of the DNA molecule. The number, size and shape of chromosomes are strictly defined and specific to each species.

In germ cells and in spores, plants have a single (haploid) set of chromosomes, in somatic cells - a double (diploid) set. There are also polyploid cells. There are homologous (paired, corresponding) and non-homologous chromosomes. The chromosomes that determine the development of sex are called sex chromosomes. The rest of the chromosomes are called autosomes.

Cytoplasm (gr. cytos - cell and plasma - fashioned) - the living contents of the cell, except for the nucleus. It consists of membranes and organelles (EPS, ribosomes, mitochondria, plastids, Golgi apparatus, lysosomes, centrioles, etc.), the space between which is filled with a colloidal solution - hyaloplasm. Outside, the cytoplasm is limited by the cell membrane, inside - by the membrane of the nuclear membrane. Plant cells also have an internal boundary membrane that separates the cell sap and forms a vacuole.

The cytoplasm contains a large amount of water with salts and organic substances dissolved in it. Cytoplasm is a medium for intracellular physiological and biochemical processes. It is capable of movement - circular, striated, ciliary.

The endoplasmic reticulum (EPS), or endoplasmic reticulum (EPR), is a network of channels that permeates the entire cytoplasm. The walls of these channels are membranes in contact with all organelles of the cell. EPS and organelles together make up a single intracellular system that carries out the metabolism and energy in the cell and provides intracellular transport of substances. There are smooth and granular EPS. The granular ER consists of membranous sacs (cistern) covered with ribosomes, making it appear rough (rough ER). ER may also be devoid of ribosomes (smooth ER); its structure is closer to the tubular type. Proteins are synthesized on the ribosomes of the granular network, which then enter the EPS channels, where they acquire a tertiary structure. On the membranes of smooth ER, lipids and carbohydrates are synthesized, which also enter the ER channels.

ER performs the following functions: participates in the synthesis of organic substances, transports the synthesized substances to the Golgi apparatus, divides the cell into compartments. In addition, in liver cells, EPS is involved in the neutralization of toxic substances, and in muscle cells it plays the role of a calcium depot, which is necessary for muscle contraction.

EPS is present in all cells, excluding bacterial cells and erythrocytes; it makes up 30 to 50% of the cell volume.

The Golgi complex (apparatus) is a complex network of cavities, tubules and vesicles around the nucleus. It consists of three main components: a group of membrane cavities, a system of tubes extending from the cavities, and vesicles at the ends of the tubes. The Golgi complex performs the following functions: substances accumulate in the cavities, which are synthesized and transported through the ER; here they undergo chemical changes. Modified substances are packed into membrane vesicles, which are released by the cell in the form of secrets. In addition, the vesicles are used by the cell as lysosomes.

Lysosomes (gr. lysio - dissolve, soma - body) are small vesicles with a diameter of about 1 micron, limited by a membrane and containing a complex of enzymes that ensures the breakdown of fats, carbohydrates and proteins. They are involved in the digestion of particles that have entered the cell as a result of endocytosis, and in the removal of dying organs (for example, the tail of tadpoles), cells and organelles. During starvation, lysosomes dissolve some organelles without killing the cell. Lysosomes are formed in the Golgi complex.

Mitochondria (gr. mitos - thread and chondrion - granule) - intracellular organelles, the shell of which consists of two membranes. The outer membrane is smooth, the inner one forms outgrowths called cristae. Inside the mitochondrion is a semi-liquid matrix that contains RNA, DNA, proteins, lipids, carbohydrates, enzymes, ATP and other substances; the matrix also contains ribosomes.

The size of mitochondria is from 0.2-0.4 to 1-7 microns. The number depends on the type of cell, for example, in a liver cell there may be 1000-2500 mitochondria. Mitochondria can be spiral, round, elongated, cupped, etc.; can also change shape.

The functions of mitochondria are related to the fact that respiratory enzymes and ATP synthesis enzymes are located on the inner membrane. Due to this, mitochondria provide cellular respiration and ATP synthesis.

Mitochondria can synthesize proteins themselves, since they have their own DNA, RNA and ribosomes. Mitochondria reproduce by dividing in two.

In their structure, mitochondria resemble prokaryotic cells; in this regard, it is assumed that they originated from intracellular aerobic symbionts. Mitochondria are found in the cytoplasm of most plant and animal cells.

Chloroplasts are plastids, organelles found only in plant cells. These are green plates with a diameter of 3-4 microns, having an oval shape. Chloroplasts, like mitochondria, have outer and inner membranes. The inner membrane forms outgrowths - thylakoids, thylakoids form stacks - grana, which are combined with each other by the inner membrane. One chloroplast can contain several tens of grains. Chlorophyll is located in the thylakoid membranes, and ribosomes, RNA and DNA are located in the spaces between the grana in the matrix (stroma) of the chloroplast. Chloroplast ribosomes, like mitochondrial ribosomes, synthesize proteins. The main function of chloroplasts is to ensure the process of photosynthesis: the light phase occurs in the thylakoid membranes, and the dark phase of photosynthesis occurs in the stroma of chloroplasts. In the matrix of chloroplasts, granules of primary starch are visible, that is, starch synthesized in the process of photosynthesis from glucose. Chloroplasts, like mitochondria, reproduce by fission. Thus, there are common features in the morphological and functional organization of mitochondria and chloroplasts. The main characteristic that unites these organelles is that they have their own genetic information and synthesize their own proteins.

The cell center refers to the non-membrane components of the cell. It consists of microtubules and two centrioles. Centrioles are located in the middle of the center of microtubule organization. Centrioles

not found in all cells with a cell center (for example, they are not found in angiosperms). Each centriole is a cylinder about 1 μm in size, around which nine triplets of microtubules are located. The centrioles are at right angles to each other. The cell center plays an important role in the organization of the cytoskeleton, since cytoplasmic microtubules diverge in all directions from this area. Before dividing, centrioles diverge to opposite poles of the cell, and a daughter centriole appears near each of them. Microtubules extend from the centrioles to form the mitotic spindle. Part of the spindle threads is attached to the chromosomes. The formation of spindle fibers occurs in prophase.

Ribosomes are submicroscopic organelles with a diameter of 15-35 nm, which have been discovered in all cells using an electron microscope. Each cell can have several thousand ribosomes. Ribosomes can be of nuclear, mitochondrial and plastid origin. Most of it is formed in the nucleolus of the nucleus in the form of subunits (large and small) and then passes into the cytoplasm. There are no membranes. Ribosomes are composed of rRNA and proteins. Protein synthesis takes place on ribosomes. Most of the proteins are synthesized on the rough ER; partially, protein synthesis occurs on ribosomes that are in the cytoplasm in a free state. Groups of several dozen ribosomes form polysomes.

Cellular organelles of movement include cilia and flagella - outgrowths of the membrane with a diameter of about 0.25 microns, containing microtubules in the middle. Such organelles are found in many cells (in protozoa, unicellular algae, zoospores, spermatozoa, in tissue cells of multicellular animals, for example, in the respiratory epithelium).

The function of these organelles is either to provide movement. ion (for example, in protozoa), or in the promotion of fluid along the surface of cells (for example, in the respiratory epithelium to promote mucus).

Cells can also move with the help of the formation of pseudopodia (pseudopodia; for example, amoeba and leukocytes), but pseudopodia are temporary formations that are not classified as organelles of movement.

Cellular inclusions are non-permanent structures of the cell. These include drops and grains of proteins, carbohydrates, fats, as well as crystalline inclusions - organic crystals that can form proteins, viruses, oxalic acid salts, etc. in cells, and inorganic crystals formed by calcium salts. Unlike organelles, these inclusions do not have membranes or elements of the cytoskeleton and are periodically synthesized and consumed.

Drops of fat are used as a reserve substance due to its high energy content; grains of carbohydrates in the form of starch in plants and in the form of glycogen in animals and fungi - as an energy source for the formation of ATP; protein grains - as a source of building material, calcium salts - to ensure the process of excitation, metabolism, etc.

Choose one correct answer.

In plant, fungal, and bacterial cells, the cell wall consists of

1) only n proteins 3) from proteins and lipids

2) only from lipids 4) from polysaccharides

The glycocalyx is the outer layer of cells

1) animals

2) all prokaryotes

They have a two-membrane structure

1) mitochondria

2) lysosomes

Plastids are present in cells

1) all plants

2) only animals

Chloroplasts are cell organelles that

1) cellular respiration occurs

2) the process of photosynthesis is carried out

3) there are red and yellow pigments

4) secondary starch accumulates

6. Occurs in mitochondria

1) accumulation of substances synthesized by the cell

2) cellular respiration with energy storage

3) formation of the tertiary structure of the protein

4) dark phase of photosynthesis

7. A rough endoplasmic reticulum is such a network, on the walls of which there are many

1) mitochondria 3) ribosomes

2) lysosomes 4) leukoplasts

8. Synthesis occurs on the membranes of the agranular endoplasmic reticulum

1) ATP 3) nucleic acids

2) carbohydrates 4) proteins

9. The function of the Golgi complex is to

1) (accumulation of proteins for subsequent excretion

2) protein synthesis and their subsequent excretion

3) accumulation of proteins for subsequent cleavage

4) the synthesis of proteins and their subsequent cleavage

10. Digestive enzymes are found in

1) ribosomes 3) mitochondria

2) lysosomes 4) leukoplasts

11. L isosomes are involved in

1) transport of substances synthesized in the cell

2) accumulation, chemical modification and packaging of substances synthesized in the cell

3) protein synthesis

4) removal of obsolete cell organelles

12. The cell center is involved in

1) ATP synthesis

2) storage of genetic information

3) the formation of the fission spindle

4) ribosome synthesis

13. The main structures of the cell center are

1) thylakoids 3) centrioles

2) grana 4) membranous vesicles

14. The nucleolus is involved in

1) energy metabolism

2) the synthesis of ribosomes

3) organization of cell division

4) transport of substances synthesized in the cell

15. Chromosomes are made up of

1) DNA 3) RNA

2) DNA and proteins 4) RNA and proteins

Choose three correct answers.

16. Membrane cell organelles are

1) lysosomes

2) ribosomes

3) endoplasmic reticulum

4) centrioles

5) Golgi complex

6) microtubules of the cytoskeleton

17. Endoplasmic reticulum

1) is a source of cell lysosomes

2) participates in the synthesis of organic compounds

3) provides transport of substances

4) divides the cell into separate compartments

5) forms ribosomes

6) ensures the removal of dying cell organelles

18. Plasmalemma

1) is a barrier between the cytoplasm of the cell and the external environment

2) provides transport of amino acids to the site of protein synthesis

3) provides selective transport of substances into the cell

4) participates in intercellular interactions

5) serves as a depot of reserve nutrients

6) participates in the accumulation and chemical modification of substances synthesized in the cell

19. Ribosomes

1) Surrounded by a double membrane

2) are on the surface of the rough endoplasmic reticulum

3) consist of two subunits

4) carry out intracellular digestion

5) form a division spindle

6) participate in protein synthesis

20. Nuclear envelope

1) has a thickness of about 30 nm

2) separates the nucleus from the cytoplasm

3) is impermeable to nucleic acid molecules

4) consists of two membranes

5) riddled with pores

6) does not contain phospholipids

21. Establish a correspondence between the cell organoid and the function it performs.

Quest Keys

question number	1	2	3	4	5	6	7	8	9	10
answer	4	1	1	1	2	2	3	2	1	2
question number	11	12	13	14	15	16	17	18	19	20
answer	4	3	3	2	2	1,3,5	2,3,4	1,3,4	2,3,6	2,4,5

Task 21

1	2	3	4	5	6
A	B	IN	A	A	IN

Separated from the environment by the plasmalemma, it includes the main substance (matrix and hyaloplasm), the obligatory cellular components in it - organelles, as well as various non-permanent structures - inclusions.

In an electron microscope, the cytoplasmic matrix looks like a homogeneous or fine-grained substance with a low electron density. The main substance of the cytoplasm fills the space between the plasmalemma, the nuclear membrane and other intracellular structures. Hyaloplasm is a complex colloidal system that includes various biopolymers. The main substance of the cytoplasm forms the true internal environment of the cell, which unites all intracellular structures and ensures their interaction with each other.

In an electron microscope, the cytoplasmic matrix looks like a homogeneous or fine-grained substance with a low electron density. It includes a microtrabecular network formed by thin fibrils 2-3 nm thick and penetrating the entire cytoplasm. The main substance of the cytoplasm should be considered in the same way as a complex colloidal system capable of moving from a liquid state to a gel-like one.

Functions:

It unites all cellular structures and ensures their interaction with each other.

It is a reservoir for enzymes and ATP.

Spare products are put aside.

Various reactions (protein synthesis) take place.

The constancy of the environment.

It is a framework.

Inclusions are called non-permanent components of the cytoplasm, which serve as reserve nutrients, products to be removed from the cell, and ballast substances.

Organelles are permanent structures of the cytoplasm that perform vital functions in the cell.

Non-membrane organelles:

1) Ribosomes- small mushroom-shaped bodies in which protein synthesis takes place. They consist of ribosomal RNA and a protein that forms a large and small subunit.

2) cytoskeleton- the musculoskeletal system of the cell, including non-membrane formations that perform both frame and motor functions in the cell. These filamentous or fibrillar-nye can quickly appear and just as quickly disappear. This system includes fibrillar structures (5-7nm) and microtubules (they consist of 13 subunits).

3) The cell center consists of centrioles (150 nm long, 300-500 nm in diameter) surrounded by centrospheres.

Centrioles are made up of 9 triplets of microtubules. Functions:

The formation of mitotic spindle filaments.

Ensuring the separation of sister chromatids in the anaphase of mitosis.

4) Cilia (A cilia is a thin cylindrical outgrowth of the cytoplasm with a constant diameter of 300 nm. This outgrowth is covered with a plasma membrane from the base to its very top) and flagella (150 microns long) are special movement organelles found in some cells of various organisms .

It is known that most living beings consist of water in free or bound form by 70 percent or more. Where does it come from so much, where is it localized? It turns out that each cell in its composition has up to 80% water, and only the rest falls on 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 structural features and functions performed by which we will get acquainted further.

Protoplast

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

What organelles are located in the cytoplasm? This:

ribosomes;
mitochondria;
golgi apparatus;
lysosomes;
vacuoles (in plants and fungi);
cell center;
plastids (in plants);
cilia and flagella;
microfilaments;
microtubules.

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

Thus, the structural features of the cytoplasm will largely depend on the type of cell, on the organism itself, its belonging to the kingdom 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 the cell consists primarily of its division into parts:

hyaloplasm - permanent liquid part;
organelles;
inclusions are structure variables.

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

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

colorless, viscous colloidal substance, quite thick and slimy;
has a clear differentiation in structural organization, however, due to mobility, it can easily change it;
from the inside it is represented by a cytoskeleton or a microtrabecular lattice, which is formed due to protein filaments (microtubules and microfilaments);
all the structural parts of the cell as a whole are located on the parts of this lattice, and due to microtubules, the Golgi apparatus and the ER, a message occurs between them through the hyaloplasm.

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

The composition of the cytoplasm

If we talk about the chemical composition, then the share of 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. Dry matter is represented by:

The general chemical reaction of the medium is alkaline or slightly alkaline. If we consider how the cytoplasm of the cell is located, then such a 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 and is called the 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 several micrometers in size. Diameter - from 6 to 25 nm. Due to too scanty indicators, a complete and capacious study of these structures is not yet possible, however, it is assumed that their walls consist of the protein substance tubulin. This compound has a chain helically twisted molecule.

Some functions of the cytoplasm in the cell are performed precisely due to the presence of microtubules. So, for example, they are involved in the alignment of fungi and plants, some bacteria. In animal cells, they are much less. Also, it is these structures that carry out the movement of organelles in the cytoplasm.

By themselves, microtubules are unstable, capable of quickly disintegrating and forming again, being renewed from time to time.

Microfilaments

Sufficiently important elements of the cytoplasm. They are long filaments of actin (globular protein), which, intertwining with each other, form a common network - the cytoskeleton. Another name is microtrabecular lattice. This is a kind of structural features of the cytoplasm. After all, it is thanks to such a cytoskeleton that all organelles are held together, they can safely communicate with each other, substances and molecules pass through them, and metabolism is carried out.

However, it is known that the cytoplasm is the internal environment of the cell, which is often capable of changing its physical data: becoming more liquid or viscous, changing its structure (transition from sol to gel and vice versa). In this regard, microfilaments are a dynamic, labile part that can quickly rebuild, change, disintegrate and form again.

Plasma membranes

The presence of well-developed and normally functioning numerous membrane structures is important for the cell, which also constitutes a kind of structural features of the cytoplasm. After all, it is through the plasma membrane barriers that molecules, nutrients and metabolic products, gases for respiration processes, and so on are transported. That is why most organelles have these structures.

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

The structure of most of them is similar - a fluid-mosaic model, which considers each plasmalemma as a biolayer of lipids, permeated with different protein molecules.

Since the functions of the cytoplasm in the cell are primarily a transport message between all its parts, the presence of membranes in most organelles is one of the structural parts of the hyaloplasm. In a complex, 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 separated for some time. The basis of the composition: and protein. The main places of localization of ribosomes in the cell:

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

and golgi apparatus

Numerous network of tubules, tubules and vesicles, forming 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 organelles with each other and transporting nutrient molecules to 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 limited from the cytoplasm by membranes. Also, it is this organoid that is the site of the synthesis of fats and carbohydrates.

Peroxisomes and lysosomes

Lysosomes are small, round structures that resemble fluid-filled vesicles. They are very numerous and distributed in the cytoplasm, where they move freely within the cell. Their main task is the dissolution of foreign particles, that is, the elimination of "enemies" in the form of dead sections of cellular structures, bacteria and other molecules.

The liquid content is saturated with enzymes, so lysosomes take part in the breakdown of macromolecules to their monomer units.

Peroxisomes are small oval or round organelles with a single membrane. Filled with liquid content, including a large number of different enzymes. They are one of the main consumers of oxygen. They perform their functions depending on the type of cell in which they are located. It is possible to synthesize myelin for the sheath of nerve fibers, and they can also carry out the oxidation and neutralization of toxic substances and various molecules.

Mitochondria

These structures are not in vain called the power (energy) stations of the cell. After all, it is in them that the formation of the main energy carriers occurs - the molecules of adenosine triphosphoric acid, or ATP. In appearance, they resemble beans. The membrane that separates the mitochondria from the cytoplasm is double. The internal structure is highly folded to increase the surface area for ATP synthesis. The folds are called cristae, they contain a large number of different enzymes to catalyze the synthesis processes.

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

Cyclosis phenomenon

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

oscillatory;
rotational, or circular;
striated.

Any movement is necessary to ensure a number of important functions of the cytoplasm: the full movement of organelles inside the hyaloplasm, the uniform exchange of nutrients, gases, energy, and the excretion of metabolites.

Cyclosis occurs in both plant and animal cells, with no exceptions. If it stops, then the body dies. Therefore, this process is also an indicator of the vital activity of beings.

Thus, we can conclude that the cytoplasm of any eukaryotic animal is a very dynamic, living structure.

The difference between the cytoplasm of animal and plant cells

Actually there are few differences. The general plan of the building, the functions performed are completely similar. However, there are still some discrepancies. For example:

In other respects, both structures are identical in composition and structure of the cytoplasm. The number of certain 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 great, if not to say that it is decisive. After all, this is the basis in which all vital structures are located, so it is difficult to overestimate its role. We can formulate several main points that reveal this meaning.

It is she who unites all the constituent parts of the cell into one complex unified system that carries out the processes of vital activity in a coordinated and cumulative manner.
Thanks to the water included in the composition, the cytoplasm in the cell acts as a medium for numerous complex biochemical interactions and physiological transformations of substances (glycolysis, nutrition, gas exchange).
This is the main "capacity" for the existence of all cell organelles.
Due to microfilaments and tubules, it forms a cytoskeleton, binding organelles and allowing them to move.
It is in the cytoplasm that a number of enzymes are concentrated, without which not a single biochemical reaction occurs.

Summing up, the following should be said. The role of the cytoplasm in the cell is practically the key, since it is the basis of all processes, the living environment and the substrate for reactions.

What is cytoplasm

Along with it, the cytoplasm is one of the main parts of the cell, this building material of any organic matter. The cytoplasm plays a very important role in the life of the cell, it unites all cellular structures, promotes their interaction with each other. Also in the cytoplasm is the nucleus of the cell and that's it. In simple words, the cytoplasm is a substance in which all other components of the cell are located.

The structure of the cytoplasm

The composition of the cytoplasm includes various chemical compounds, which are not a homogeneous chemical substance, but a complex physico-chemical system, it is also constantly changing and developing and has a large water content. An important component of the cytoplasm is a protein mixture in a colloidal state in combination with nucleic acids, fats and carbohydrates.

The cytoplasm is also divided into two parts:

endoplasm,
exoplasm.

Endoplasm is located in the center of the cell and has a more fluid structure. It is in it that all the most important organelles of the cell are located. Exoplasm is located along the perimeter of the cell, where it borders on its membrane; it is more viscous and dense in consistency. It plays the role of connecting the cell with the environment.

Cytoplasm drawing.

Functions of the cytoplasm

What is the function of the cytoplasm? Very important - all processes of cellular metabolism take place in the cytoplasm, with the exception of the synthesis of nucleic acids (it is carried out in the cell nucleus). In addition to this, the most important function, the cytoplasm plays such useful roles:

fills the cell cavity
is a link for cellular components,
determines the position of organelles,
is a conductor for physical and chemical processes at the intracellular and intercellular levels,
maintains the inner cell, its volume, elasticity, etc.

Movement of the cytoplasm

The ability of the cytoplasm to move is its important property, due to this, the connection of the cell organelles is ensured. In biology, the movement of the cytoplasm is called cyclosis, it is a constant process. The movement of the cytoplasm in the cell can be jet, oscillatory or circular.

Division of the cytoplasm

Another property of the cytoplasm is its division, without which cell division itself would simply be impossible. The division of the cytoplasm is carried out through, which you can read more about in the article at the link.