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

In addition to the features characteristic of prokaryotes and eukaryotes, the cells of plants, animals, fungi and bacteria also have a number of features. Thus, plant cells contain specific organelles - chloroplasts, which determine their ability to photosynthesize, whereas these organelles are not found in other organisms. 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 plasma membrane and individual membrane vesicles in the cytoplasm.

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

One more 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 others have it. This is entirely understandable, since the way animals feed is associated with the capture of food particles during 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 are not the same various groups living organisms: if in plants it is cellulose, then in fungi it is chitin, and in bacteria it is murein. Comparative characteristics structure of cells of plants, animals, fungi and bacteria

Sign	Bacteria	Animals	Mushrooms	Plants
Nutrition 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	Pulp
Cytoplasm	Eat	Eat	Eat	Eat
Organoids	Ribosomes	Membrane and non-membrane, including the cell center	Membrane and non-membrane	Membrane and non-membrane, including plastids
Organoids of movement	Flagella and villi	Flagella and cilia	Flagella and cilia	Flagella and cilia
Vacuoles	Rarely	Contractile, digestive	Sometimes	Central vacuole with cell juice
Inclusions	Glycogen, volutin	Glycogen	Glycogen	Starch

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

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

Chemical composition of the cell

Most of the chemical elements of D.I. Mendeleev’s Periodic Table of Elements discovered to date have been found in living organisms. On the one hand, they do not contain a single element that would not exist in inanimate nature, and on the other hand, their concentrations 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 as a whole, since they are synthesized mainly by organisms in the process of life and play a vital role in reactions.

Science studies the chemical composition of organisms and the chemical reactions occurring 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, while in plant cells carbohydrates predominate.

Chemical element	Earth's crust	sea ​​water	Living 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 established. The remaining elements are present in small quantities and, apparently, enter the body with food, water and air. The content of chemical elements in the body varies significantly. Depending on their concentration, they are divided into macroelements and microelements.

The concentration of each macronutrients in the body exceeds 0.01%, and their total content is 99%. Macroelements include oxygen, carbon, hydrogen, nitrogen, phosphorus, sulfur, potassium, calcium, sodium, chlorine, magnesium and iron. The first four of the listed 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.

Without the remaining macronutrients it is impossible normal functioning body. Thus, potassium, sodium and chlorine are involved in the processes of cell excitation. Potassium is also necessary for the functioning of many enzymes and the retention of water in the cell. Calcium is found in the cell walls of plants, bones, teeth, and mollusk shells and is required for muscle cell contraction and intracellular movement. Magnesium is a component of chlorophyll, a pigment that ensures photosynthesis occurs. It also takes part in protein biosynthesis. Iron, in addition to being 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.

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

Both deficiency and excess or disruption 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 fluoride intake from water and food to a large extent causes disruption of tooth enamel renewal and, as a consequence, 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, renal failure, seizures, 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 due to the reception medicines. Thus, iodine is found in seafood and iodized salt, calcium - in eggshells etc.

The relationship between 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 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) is the most common inorganic substance of the cell, which has unique physical and chemical properties. It has no taste, no color, no smell. The density and viscosity of all substances is assessed using water. Like many other substances, water can exist 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 gives it the opportunity to take part in thermoregulation processes. In a water molecule, the hydrogen atoms are located at an angle of 105°, while the total electron pairs are pulled away by the more electronegative oxygen atom. This determines the dipole properties of water molecules (one end is positively charged and the other negatively charged) and the possibility of the formation of hydrogen bonds between water molecules. The cohesion 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 those 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 body's cells varies and may change with age. Thus, 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, the cells of the body differ in their water content. So, the bones contain about 20% water, the liver - 70%, and the brain - 86%. In general it can be said that the concentration of water in cells is directly proportional to the metabolic rate.

Mineral salts can 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 are involved in the occurrence and conduction of nerve impulses; as well as calcium ions, which takes part in the processes of muscle fiber contraction 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 environment. Ions mineral salts ensure both the penetration of water itself into the cell and its retention in it. If the salt concentration in the environment is lower than in the cell, then water penetrates into the cell. Ions also determine the buffering 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, organisms can produce other inorganic compounds, such as acids and oxides. Thus, the parietal cells of the human stomach produce hydrochloric acid, which activates digestive enzyme pepsin, and silicon oxide permeates the cell walls of horsetails and forms the shells of diatoms. IN recent years The role of nitric oxide (II) in signaling in cells and the body is also being studied.

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 kinship 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 type of cell.

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, which do not have a formed nucleus.

All prokaryotes consist of:

• capsules that perform a protective function;
• 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, thanks to which bacteria can move.

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

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

The capsule is located on top of the shell and from unfavorable 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. Moreover, they are able to take their original form immediately as soon as they are exposed to external influences. unfavorable 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 functions. It contains the DNA of a plant or animal, and 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. The pores also remove waste products.

Plant cells are distinguished by the presence of plastids, which are located in chloroplasts, leucoplasts and chromoplasts. Chromoplasts contain substances that color fruits and stems. Most often they are yellow, red or orange in color. Due to their bright colors, plant flowers attract the attention of pollinating insects, such as bees. Leucoplasts contain a reserve nutrients, which are used when the body is in unfavorable conditions. Chloroplasts are plastids that are colored green, which are responsible for the process of photosynthesis. Chloroplasts are found only in leaves or stems.

The cell wall of plants consists of cellulose, of 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, and animals have one or more small ones. Plant vacuoles are responsible for the entry and exit of water, while animals retain water, ions, and store waste products. Fungi have no 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 others in that they are nuclear-free and are significantly smaller in size than other living beings. You'll need a fairly powerful microscope to see them.

These structures, despite the same origin, have significant differences.

General plan of cell structure

When considering cells, it is necessary first of all to remember the basic patterns 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 called inclusions are deposited in them. New cells arise as a result of the division of maternal cells. During this process, two or more young structures can be formed from one original one, which are an exact genetic copy of the original ones. Cells, uniform in their 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.

Features for comparison	plant cell	animal cell
Features of the cell wall	Consists of cellulose polysaccharide.	It is a glycocalyx, a thin layer consisting of compounds of proteins with carbohydrates and lipids.
Presence of a cell center	Found only in the cells of lower algal plants.	Found in all cells.
Presence and location of the core	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 three types of plastids: chloro-, chromo- and leucoplasts.	None.
Photosynthetic capacity	Happens on inner surface chloroplasts.	Not capable.
Nutrition method	Autotrophic.	Heterotrophic.
Vacuoles	Are large	Digestive and
Storage carbohydrate	Starch.	Glycogen.

Main differences

Comparison of plant and animal cell indicates a number of differences in the features of their structure, and therefore life processes. Thus, 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 their 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 is the way they feed. Plants have green plastids called chloroplasts in their cytoplasm. On their inner surface there is a complex chemical reaction transformation of water and carbon dioxide into monosaccharides. This process is only possible if there is sunlight and is called photosynthesis. By-product reaction is oxygen.

Conclusions

So, we have compared plant and animal cells, their similarities and differences. The common features are the building plan, chemical processes and composition, division and genetic code. At the same time, plant and animal cells are fundamentally different in the way they feed 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 is the basis of the unity of the organic world, evidence of the kinship of living nature

unity of the organic world, cell, cell theory, provisions of the cell 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 basis of cell theory was the work of many researchers who were looking for 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 precursors to the creation of the cell theory:

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

– 1665 Robert Hooke – first description of the microscopic structure of the elderberry branch plug (in fact, these were cell walls, but Hooke introduced the name “cell”);

– 1695 Publication by Anthony Leeuwenhoek about 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.

Basic provisions of modern cell theory:

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

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

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

4. B multicellular organisms cells are differentiated by structure and function. They are organized into tissues, organs and organ systems.

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

The cell theory developed due to new discoveries. In 1880, Walter Flemming described chromosomes and the processes occurring in mitosis. Since 1903, genetics began to develop. Since 1930, electron microscopy began to develop rapidly, which allowed scientists to study the finest structure of cellular structures. The 20th century was the century of the flourishing 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 the minimal structure of a living thing that has all vital properties - the ability to metabolize, grow, develop, transmit 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 consist of the same cell. Muscle cells have contractility 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 an organism is, the more diverse its cells are in their structure and functions. Each type of cell has a specific size and shape. Similarities in cell structure various organisms, the commonality of their basic properties confirms the commonality of their origin and allows us to draw a conclusion about the unity of the organic world.

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

Basic 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 shape, structure and functions, 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 section "Cell Structure".) Eukaryotic cells contain a nucleus in which the organism's genetic apparatus is located. Prokaryotic cells are cells of bacteria and blue-green algae. The cells of all other organisms are eukaryotic.

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

Modern taxonomy distinguishes the following kingdoms of organisms: Bacteria, Fungi, Plants, Animals. The basis for this division is the feeding methods of these organisms and the structure of cells.

Bacterial cells have the following structures characteristic of them - a dense cell wall, one circular DNA molecule (nucleotide), ribosomes. These cells lack many organelles characteristic of eukaryotic plant, animal and fungal cells. Based on the way they feed, bacteria are divided into autotrophs, chemotrophs And heterotrophs. Plant cells contain plastids characteristic only of them - chloroplasts, leucoplasts 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 occurs.

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 its main components. The reserve substance of fungal and animal cells is glycogen.

1. Select features characteristic only of plant cells

1) there are mitochondria and ribosomes

2) cell wall made of cellulose

3) there are chloroplasts

4) storage substance - glycogen

5) reserve substance – starch

6) the nucleus is surrounded by a double membrane

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

1) heterotrophic mode of nutrition

2) autotrophic method of nutrition

3) the presence of a nucleoid

4) absence of mitochondria

5) absence of a core

6) presence of ribosomes

Chemical organization of the cell. The relationship between 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 an analysis of the chemical composition of their cells

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

Related information.

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

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

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

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

According to the method of nutrition and cell structure, they are divided into kingdoms :

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

Bacterial cells (kingdom Drobyanka) have: a dense cell wall, one circular DNA molecule (nucleoid), ribosomes. These cells lack many organelles characteristic of eukaryotic plant, animal and fungal cells. Based on their feeding method, bacteria are divided into phototrophs, chemotrophs, and heterotrophs.

Fungal 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 its main components. The reserve substance of fungal and animal cells is glycogen.

Plant cells contain: chloroplasts, leucoplasts 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.

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

THEMATIC TASKS

Part A

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

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) cores
2) mitochondria
3) cell wall
4) ribosomes

A4. One cell consists of:
1) influenza virus and amoeba
2) mucor mushroom and cuckoo flax
3) planaria and volvox
4) green euglena and slipper ciliates

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

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

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

Part B

B1. Select features characteristic only of plant cells
1) there are mitochondria and ribosomes
2) cell wall made of cellulose
3) there are chloroplasts
4) storage substance - glycogen
5) reserve substance – starch
6) the nucleus is surrounded by a double membrane

B2. Select the characteristics that distinguish the kingdom of Bacteria from the rest of the kingdoms of the organic world.
1) heterotrophic mode of nutrition
2) autotrophic method of nutrition
3) the presence of a nucleoid
4) absence of mitochondria
5) absence of a core
6) presence of ribosomes

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

Part C

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