The structure of an animal cell and bacteria. Similarities and differences between other organisms

In addition to the features characteristic of prokaryotes and eukaryotes, the cells of plants, animals, fungi and bacteria have a number of other features. So, plant cells contain specific organelles - chloroplasts, which determine their ability to photosynthesis, while in other organisms these organelles are not found. Of course, this does not mean that other organisms are not capable of photosynthesis, since, for example, in bacteria, it occurs on invaginations of the plasmalemma and individual membrane vesicles in the cytoplasm.

Plant cells usually contain large vacuoles filled with cell sap. In the cells of animals, fungi and bacteria, they are also found, but they have a completely different origin and perform different functions. The main reserve substance found in the form of solid inclusions is starch in plants, glycogen in animals and fungi, and glycogen or volutin in bacteria.

Another hallmark of these groups of organisms is the organization of the surface apparatus: the cells of animal organisms do not have a cell wall, their plasma membrane is covered only with a thin glycocalyx, while all the rest have it. This is entirely understandable, since the way animals feed is associated with the capture of food particles in the process of phagocytosis, and the presence of a cell wall would deprive them of this opportunity. Chemical nature substances that make up the cell wall is not the same for various groups living organisms: if in plants it is cellulose, then in fungi it is chitin, and in bacteria it is murein. Comparative characteristics cell structures of plants, animals, fungi and bacteria

sign	bacteria	Animals	Mushrooms	Plants
Feeding method	heterotrophic or autotrophic	Heterotrophic	Heterotrophic	autotrophic
Organization of hereditary information	prokaryotes	eukaryotes	eukaryotes	eukaryotes
DNA localization	Nucleoid, plasmids	nucleus, mitochondria	nucleus, mitochondria	Nucleus, mitochondria, plastids
plasma membrane	Eat	Eat	Eat	Eat
cell wall	Mureinovaya	-	Chitinous	Cellulosic
Cytoplasm	Eat	Eat	Eat	Eat
Organelles	Ribosomes	Membrane and non-membrane, including the cell center	Membrane and non-membrane	Membrane and non-membrane, including plastids
Organelles of movement	Flagella and villi	Flagella and cilia	Flagella and cilia	Flagella and cilia
Vacuoles	Rarely	contractile, digestive	Sometimes	central vacuole with cell sap
Inclusions	Glycogen, volutin	Glycogen	Glycogen	Starch

Differences in the structure of cells of representatives different kingdoms wildlife are shown in the figure.

The chemical composition of the cell. Macro- and microelements. The relationship of the structure and functions of inorganic and organic matter(proteins, nucleic acids, carbohydrates, lipids, ATP) that make up the cell. Role chemical substances in the cell and the human body

The chemical composition of the cell

In the composition of living organisms, most of the chemical elements of the Periodic Table of Elements of D. I. Mendeleev, discovered to date, have been found. On the one hand, they do not contain a single element that would not be in inanimate nature, and on the other hand, their concentration in bodies inanimate nature and living organisms differ significantly.

These chemical elements form inorganic and organic substances. Despite the fact that inorganic substances predominate in living organisms, it is organic substances that determine the uniqueness of their chemical composition and the phenomenon of life in general, since they are synthesized mainly by organisms in the process of vital activity and play an important role in reactions.

Science deals with the study of the chemical composition of organisms and the chemical reactions that take place in them. biochemistry.

It should be noted that the content of chemicals in different cells and tissues can vary significantly. For example, if in animal cells among organic compounds proteins predominate, then in plant cells - carbohydrates.

Chemical element	Earth's crust	Sea water	Alive organisms
O	49.2	85.8	65–75
C	0.4	0.0035	15–18
H	1.0	10.67	8–10
N	0.04	0.37	1.5–3.0
P	0.1	0.003	0.20–1.0
S	0.15	0.09	0.15–0.2
K	2.35	0.04	0.15–0.4
Ca	3.25	0.05	0.04–2.0
Cl	0.2	0.06	0.05–0.1
mg	2.35	0.14	0.02–0.03
Na	2.4	1.14	0.02–0.03
Fe	4.2	0.00015	0.01–0.015
Zn	< 0.01	0.00015	0.0003
Cu	< 0.01	< 0.00001	0.0002
I	< 0.01	0.000015	0.0001
F	0.1	2.07	0.0001

Macro- and microelements

About 80 chemical elements are found in living organisms, but only 27 of these elements have their functions in the cell and organism. The rest of the elements are present in trace amounts, and appear to be ingested through food, water, and air. The content of chemical elements in the body varies significantly. Depending on the concentration, they are divided into macronutrients and microelements.

The concentration of each macronutrients in the body exceeds 0.01%, and their total content is 99%. Macronutrients include oxygen, carbon, hydrogen, nitrogen, phosphorus, sulfur, potassium, calcium, sodium, chlorine, magnesium, and iron. The first four of these elements (oxygen, carbon, hydrogen and nitrogen) are also called organogenic, since they are part of the main organic compounds. Phosphorus and sulfur are also components of a number of organic substances, such as proteins and nucleic acids. Phosphorus is essential for the formation of bones and teeth.

Impossible without the remaining macronutrients normal functioning organism. So, potassium, sodium and chlorine are involved in the processes of excitation of cells. Potassium is also needed for many enzymes to function and to retain water in the cell. Calcium is found in the cell walls of plants, bones, teeth, and mollusk shells, and is required for muscle contraction and intracellular movement. Magnesium is a component of chlorophyll - a pigment that ensures the flow of photosynthesis. It also takes part in protein biosynthesis. Iron, in addition to being a part of hemoglobin, which carries oxygen in the blood, is necessary for the processes of respiration and photosynthesis, as well as for the functioning of many enzymes.

trace elements are contained in the body in concentrations of less than 0.01%, and their total concentration in the cell does not even reach 0.1%. Trace elements include zinc, copper, manganese, cobalt, iodine, fluorine, etc. Zinc is part of the pancreatic hormone molecule insulin, copper is required for photosynthesis and respiration. Cobalt is a component of vitamin B12, the absence of which leads to anemia. Iodine is essential for hormone synthesis thyroid gland, which ensure the normal course of metabolism, and fluorine is associated with the formation of tooth enamel.

Both a lack and an excess or a violation of the metabolism of macro- and microelements lead to the development various diseases. In particular, a lack of calcium and phosphorus causes rickets, a lack of nitrogen causes severe protein deficiency, iron deficiency - anemia, and the lack of iodine - a violation of the formation of thyroid hormones and a decrease in metabolic rate. Reducing the intake of fluoride from water and food in to a large extent causes a violation of the renewal of tooth enamel and, as a result, a predisposition to caries. Lead is toxic to almost all organisms. Its excess causes irreversible damage to the brain and central nervous system which is manifested by loss of vision and hearing, insomnia, kidney failure, convulsions, and can also lead to paralysis and diseases such as cancer. Acute poisoning lead is accompanied by sudden hallucinations and ends in coma and death.

The lack of macro- and microelements can be compensated by increasing their content in food and drinking water, as well as by taking medicines. So, iodine is found in seafood and iodized salt, calcium - in eggshell and so on.

The relationship of the structure and functions of inorganic and organic substances (proteins, nucleic acids, carbohydrates, lipids, ATP) that make up the cell. The role of chemicals in the cell and the human body

inorganic substances

Chemical elements cells form various compounds - inorganic and organic. The inorganic substances of the cell include water, mineral salts, acids, etc., and the organic substances include proteins, nucleic acids, carbohydrates, lipids, ATP, vitamins, etc.

Water(H 2 O) - the most common inorganic substance of the cell, which has unique physical and chemical properties. It has no taste, no color, no smell. Density and viscosity of all substances are estimated by water. Like many other substances, water can be in three states of aggregation: solid (ice), liquid and gaseous (steam). The melting point of water is 0°C, the boiling point is 100°C, however, the dissolution of other substances in water can change these characteristics. The heat capacity of water is also quite high - 4200 kJ / mol·K, which makes it possible for it to take part in the processes of thermoregulation. In a water molecule, hydrogen atoms are located at an angle of 105 °, while the total electron pairs pulled away by the more electronegative oxygen atom. This determines the dipole properties of water molecules (one of their ends is positively charged and the other is negatively charged) and the possibility of the formation of hydrogen bonds between water molecules. The adhesion of water molecules underlies the phenomenon of surface tension, capillarity and the properties of water as a universal solvent. As a result, all substances are divided into soluble in water (hydrophilic) and insoluble in it (hydrophobic). Thanks to these unique properties It is predetermined that water has become the basis of life on Earth.

The average water content in the cells of the body is not the same and may change with age. So, in a one and a half month old human embryo, the water content in the cells reaches 97.5%, in an eight month old - 83%, in a newborn it decreases to 74%, and in an adult it averages 66%. However, body cells differ in water content. So, the bones contain about 20% water, the liver - 70%, and the brain - 86%. On the whole, it can be said that the concentration of water in cells is directly proportional to the metabolic rate.

mineral salts may be in dissolved or undissolved states. Soluble salts dissociate into ions - cations and anions. The most important cations are potassium and sodium ions, which facilitate the transfer of substances across the membrane and participate in the occurrence and conduction of a nerve impulse; as well as calcium ions, which takes part in the processes of contraction of muscle fibers and blood clotting; magnesium, which is part of chlorophyll; iron, which is part of a number of proteins, including hemoglobin. The most important anions are the phosphate anion, which is part of ATP and nucleic acids, and the carbonic acid residue, which softens fluctuations in the pH of the medium. ions mineral salts provide both the penetration of the water itself into the cell, and its retention in it. If the concentration of salts in the environment is lower than in the cell, then water penetrates into the cell. Ions also determine the buffer properties of the cytoplasm, i.e., its ability to maintain a constant slightly alkaline pH of the cytoplasm, despite the constant formation of acidic and alkaline products in the cell.

Insoluble salts(CaCO 3, Ca 3 (PO 4) 2, etc.) are part of the bones, teeth, shells and shells of unicellular and multicellular animals.

In addition, other inorganic compounds, such as acids and oxides, can be produced in organisms. Thus, the parietal cells of the human stomach produce hydrochloric acid, which activates digestive enzyme pepsin, and silicon oxide impregnates the cell walls of horsetails and forms diatom shells. IN last years the role of nitric oxide (II) in signaling in cells and the body is also being investigated.

organic matter

All living things on our planet are made up of cells. The cellular structure of all living beings is the basis of the relationship of all living things that exist on our planet. But there are many significant differences between the cells of plants, fungi, bacteria and animals. To understand how they are similar and how they differ, you need to consider in detail the structure of each of the cell types.

How are bacteria different from other organisms?

The main thing that distinguishes bacteria (prokaryotes) from other living organisms (eukaryotes) is that they are the oldest creatures on the planet that do not have a formed nucleus in their composition.

All prokaryotes are made up of:

• capsules that perform a protective function;
• the nuclear substance in which genetic data is stored;
• cytoplasm, which provides communication between organelles;
• , which ensures the preservation of shape and is responsible for the regulation of gases and water;
• flagella that enable bacteria to move.

Since unicellular bacteria do not have a formed nucleus in their composition, its functions are performed by the nucleoid, which stores DNA and all genetic data. A nucleoid is a region of the cytoplasm that stores genetic information about an organism.

The cytoplasm is a liquid that contains the nutrients necessary for life and a large number of squirrel. Also in the cytoplasm are ribosomes that synthesize protein.

The capsule is on top of the shell and from adverse external influences, for example, from drying out and damage.

One of the features of the cellular structure of prokaryotes is that when exposed to external factors they can change their shape. At the same time, they are able to take their original form immediately, as soon as the impact of external adverse factors stops. This process is called sporulation.

Cellular structure of plants, fungi and animals

All animals, fungi and plants have much in common in their structure. As part of their cells, they all have:

• core;
• mitochondria;
• cytoplasmic membrane;
• endoplasmic reticulum;
• cytoplasm;
• golgi apparatus.

The nucleus is the main and largest element of the cell, which is responsible for its vital activity. It contains the DNA of a plant or animal, the synthesis of RNA and ribosomes occurs. The shape of the nucleus in all organisms is most often spherical.

The cytoplasmic membrane protects the contents from external influences. It has pores through which nutrients and water enter. Waste products are also removed through the pores.

Plant cells are distinguished by the presence of plastids, which are located in chloroplasts, leukoplasts and chromoplasts. Chromoplasts contain substances that color fruits and stems. Most often they are yellow, red or orange in color. Due to the bright coloring, the flowers of plants attract the attention of pollinating insects, for example, bees. Leucoplasts contain a reserve nutrients, which are used when the body is in adverse conditions. Chloroplasts are plastids stained with green color which are responsible for the process of photosynthesis. Chloroplasts are found only in leaves or stems.

The cell wall of plants consists of cellulose, fungi - of chitin, and in animals it is absent altogether. At the same time, animal and fungal cells store glycogen, while plant cells store starch.

The Golgi apparatus is responsible for the production and accumulation of polysaccharides and complex proteins.

The number of vacuoles in animal and plant cells varies. Plants have one large vacuole, while animals have one or more small ones. Plant vacuoles are responsible for the input and output of water, while animals retain water, ions and store waste products. Mushrooms do not have vacuoles at all.

A feature of fungal cells is that they usually have more than one nucleus. Under a microscope, you can see from 1 to 30 nuclei.

General and excellent

As mentioned above, the structure of prokaryotes differs from the rest in that they are non-nuclear and in size they are much smaller than other living beings. To see them, you need a fairly powerful microscope.

These structures, despite the unity of origin, have significant differences.

General plan of cell structure

Considering cells, it is necessary first of all to recall the basic laws of their development and structure. They have common structural features, and consist of surface structures, cytoplasm and permanent structures - organelles. As a result of vital activity, organic substances, which are called inclusions, are deposited in them in reserve. New cells arise as a result of the division of maternal ones. During this process, two or more young structures can be formed from one initial structure, which are an exact genetic copy of the original ones. Cells that have the same structural features and functions are combined into tissues. It is from these structures that the formation of organs and their systems occurs.

Comparison of plant and animal cells: table

On the table you can easily see all the similarities and differences in the cells of both categories.

Signs for comparison	plant cell	animal cell
Features of the cell wall	Consists of cellulose polysaccharide.	It is a glycocalyx-thin layer consisting of compounds of proteins with carbohydrates and lipids.
The presence of a cell center	It is found only in the cells of lower algae plants.	Found in all cells.
The presence and location of the nucleus	The core is located in the near-wall zone.	The nucleus is located in the center of the cell.
Presence of plastids	The presence of plastids of three types: chloro-, chromo- and leucoplasts.	None.
The ability to photosynthesis	Happens on inner surface chloroplasts.	Not capable.
Feeding method	Autotrophic.	Heterotrophic.
Vacuoles	They are large	Digestive and
Reserve carbohydrate	Starch.	Glycogen.

Main differences

Comparison of vegetable and animal cell indicates a number of differences in the features of their structure, and hence the processes of life. So, despite the unity of the general plan, their surface apparatus differs in chemical composition. Cellulose, which is part of the cell wall of plants, gives them a permanent shape. Animal glycocalyx, on the contrary, is a thin elastic layer. However, the most important fundamental difference between these cells and the organisms they form lies in the way they feed. Plants have green plastids called chloroplasts in their cytoplasm. On their inner surface, a complex chemical reaction water transformation and carbon dioxide into monosaccharides. This process is only possible if sunlight and is called photosynthesis. by-product reaction is oxygen.

conclusions

So, we compared the plant and animal cells, their similarities and differences. Common are the building plan, chemical processes and composition, division and genetic code. At the same time, plant and animal cells fundamentally differ in the way they nourish the organisms they form.

Cell theory, its main provisions, role in the formation of the modern natural-science picture of the world. Development of knowledge about the cell. The cellular structure of organisms, the similarity of the structure of the cells of all organisms - the basis of the unity of the organic world, evidence of the relationship of living nature

unity of the organic world, cell, cell theory, positions of the cellular theory.

We have already said that scientific theory is a generalization of scientific data about the object of study. This fully applies to the cell theory created by two German researchers M. Schleiden and T. Schwann in 1839.

The cell theory was based on the work of many researchers who were looking for an elementary structural unit alive. The creation and development of cell theory was facilitated by the emergence in the 16th century. And further development microscopy.

Here are the main events that became the forerunners of the creation of the cell theory:

- 1590 - the creation of the first microscope (Jansen brothers);

- 1665 Robert Hooke - the first description of the microscopic structure of the cork of the elderberry branch (in fact, these were cell walls, but Hooke introduced the name "cell");

- 1695 Anthony Leeuwenhoek's publication on microbes and other microscopic organisms he saw through a microscope;

- 1833 R. Brown described the nucleus of a plant cell;

– 1839 M. Schleiden and T. Schwann discovered the nucleolus.

The main provisions of modern cell theory:

1. All simple and complex organisms consist of cells capable of exchanging with environment substances, energy, biological information.

2. A cell is an elementary structural, functional and genetic unit of the living.

3. A cell is an elementary unit of reproduction and development of living things.

4. In multicellular organisms cells are differentiated in structure and function. They are combined into tissues, organs and organ systems.

5. A cell is an elementary, open living system capable of self-regulation, self-renewal and reproduction.

Cell theory has evolved thanks to new discoveries. In 1880, Walter Flemming described chromosomes and the processes that take place in mitosis. Since 1903, genetics began to develop. Beginning in 1930, electron microscopy began to develop rapidly, which allowed scientists to study the finest structure of cellular structures. The 20th century was the heyday of biology and such sciences as cytology, genetics, embryology, biochemistry, and biophysics. Without the creation of the cell theory, this development would have been impossible.

So, the cell theory states that all living organisms are made up of cells. A cell is that minimal structure of a living thing that has all the vital properties - the ability to metabolism, growth, development, transfer of genetic information, self-regulation and self-renewal. The cells of all organisms have similar structural features. However, cells differ from each other in their size, shape, and function. An ostrich egg and a frog egg are made up of the same cell. muscle cells are contractile and nerve cells carry out nerve impulses. Differences in the structure of cells largely depend on the functions they perform in organisms. The more complex the organism is, the more diverse in structure and functions of its cells. Each type of cell has a specific size and shape. Similarities in the structure of cells various organisms, the commonality of their basic properties confirm the commonality of their origin and allow us to draw a conclusion about the unity of the organic world.

A cell is a unit of structure, life activity, growth and development of organisms. variety of cells. Comparative characteristics of cells of plants, animals, bacteria, fungi

The main terms and concepts tested in the examination paper: bacterial cells, fungal cells, plant cells, animal cells, prokaryotic cells, eukaryotic cells.

We have already said that cells can differ from each other in form, structure and function, although the main structural elements most cells are similar. Biologists distinguish two large systematic groups of cells - prokaryotic And eukaryotic . Prokaryotic cells do not contain a true nucleus and a number of organelles. (See the Cell Structure section.) Eukaryotic cells contain a nucleus in which the hereditary apparatus of the body is located. Prokaryotic cells are cells of bacteria, blue-green algae. The cells of all other organisms are eukaryotic.

Every organism develops from a cell. This applies to organisms that were born as a result of both asexual and sexual reproduction methods. That is why the cell is considered a unit of growth and development of the organism.

Modern systematics distinguishes the following kingdoms of organisms: Bacteria, Fungi, Plants, Animals. The grounds for such a division are the methods of nutrition of these organisms and the structure of the cells.

bacterial cells have the following structures characteristic of them - a dense cell wall, one circular DNA molecule (nucleotide), ribosomes. These cells lack many of the organelles characteristic of eukaryotic plant, animal, and fungal cells. According to the mode of nutrition, bacteria are divided into autotrophs, chemotrophs And heterotrophs. Plant cells contain plastids characteristic only of them - chloroplasts, leukoplasts and chromoplasts; they are surrounded by a dense cell wall of cellulose, and also have vacuoles with cell sap. All green plants are autotrophic organisms.

Animal cells do not have dense cell walls. They are surrounded cell membrane through which the exchange of substances with the environment takes place.

Fungal cells are covered with a cell wall that differs in chemical composition from plant cell walls. It contains chitin, polysaccharides, proteins and fats as the main components. Glycogen is the reserve substance of fungal and animal cells.

1. Select features that are characteristic only for plant cells

1) have mitochondria and ribosomes

2) cellulose cell wall

3) there are chloroplasts

4) reserve substance - glycogen

5) reserve substance - starch

6) the nucleus is surrounded by a double membrane

2. Select the features that distinguish the kingdom of Bacteria from the rest of the kingdoms of the organic world.

1) heterotrophic mode of nutrition

2) autotrophic mode of nutrition

3) the presence of a nucleoid

4) lack of mitochondria

5) no core

6) the presence of ribosomes

The chemical organization of the cell. The relationship of the structure and functions of inorganic and organic substances (proteins, nucleic acids, carbohydrates, lipids, ATP) that make up the cell. Justification of the relationship of organisms based on the analysis of the chemical composition of their cells

The main terms and concepts tested in the examination paper: nitrogenous bases, enzyme active site, hydrophilicity, hydrophobicity, amino acids, ATP, proteins, biopolymers, denaturation, DNA, deoxyribose, complementarity, lipids, monomer, nucleotide, peptide bond, polymer, carbohydrates, ribose, RNA, enzymes, phospholipids.

Similar information.

The science that studies the structure and function of cells cytology .

Cells may differ from each other in form, structure, and function, although the basic structural elements of most cells are similar. Systematic groups of cells - prokaryotic And eukaryotic (superkingdoms of prokaryotes and eukaryotes) .

Prokaryotic cells do not contain a true nucleus and a number of organelles (the kingdom of the shotgun).
Eukaryotic cells contain a nucleus in which the hereditary apparatus of the organism is located (superkingdoms of fungi, plants, animals).

Every organism develops from a cell.
This applies to organisms that were born as a result of both asexual and sexual reproduction methods. That is why the cell is considered a unit of growth and development of the organism.

According to the method of nutrition and the structure of cells, they are isolated kingdoms :

• Drobyanki;
• Mushrooms;
• Plants;
• Animals.

bacterial cells (Drobyanka's kingdom) have: a dense cell wall, one circular DNA molecule (nucleoid), ribosomes. These cells lack many of the organelles characteristic of eukaryotic plant, animal, and fungal cells. According to the mode of nutrition, bacteria are divided into phototrophs, chemotrophs, and heterotrophs.

mushroom cells covered with a cell wall that differs in chemical composition from the cell walls of plants. It contains chitin, polysaccharides, proteins and fats as the main components. Glycogen is the reserve substance of fungal and animal cells.

plant cells contain: chloroplasts, leukoplasts and chromoplasts; they are surrounded by a dense cell wall of cellulose, and also have vacuoles with cell sap. All green plants are autotrophic organisms.

At animal cells no dense cell walls. They are surrounded by a cell membrane through which the exchange of substances with the environment takes place.

THEMATIC ASSIGNMENTS

Part A

A1. Which of the following is consistent with the cell theory
1) the cell is elementary unit heredity
2) the cell is the unit of reproduction
3) the cells of all organisms are different in their structure
4) the cells of all organisms have a different chemical composition

A2. Precellular life forms include:
1) yeast
2) penicillium
3) bacteria
4) viruses

A3. A plant cell differs from a fungal cell in structure:
1) kernels
2) mitochondria
3) cell wall
4) ribosome

A4. One cell consists of:
1) influenza virus and amoeba
2) mushroom mukor and cuckoo flax
3) planaria and volvox
4) euglena green and infusoria-shoe

A5. Prokaryotic cells have:
1) core
2) mitochondria
3) Golgi apparatus
4) ribosomes

A6. The species affiliation of the cell is indicated by:
1) the shape of the nucleus
2) number of chromosomes
3) membrane structure
4) the primary structure of the protein

A7. The role of cell theory in science is
1) opening of the cell nucleus
2) cell opening
3) generalization of knowledge about the structure of organisms
4) discovery of metabolic mechanisms

Part B

IN 1. Select features that are characteristic only for plant cells
1) have mitochondria and ribosomes
2) cellulose cell wall
3) there are chloroplasts
4) reserve substance - glycogen
5) reserve substance - starch
6) the nucleus is surrounded by a double membrane

AT 2. Select the features that distinguish the kingdom of Bacteria from the rest of the kingdoms of the organic world.
1) heterotrophic mode of nutrition
2) autotrophic mode of nutrition
3) the presence of a nucleoid
4) lack of mitochondria
5) no core
6) the presence of ribosomes

VZ. Find a correspondence between the structural features of the cell and the kingdom to which these cells belong

Part C

C1. Give examples of eukaryotic cells that do not have a nucleus.
C2. Prove that the cell theory generalized a number of biological discoveries and predicted new discoveries.