Ege cell chemical composition structure. Material for preparing for the exam (GIA) in biology (grade 11) on the topic: The chemical composition of the cell (preparation for the exam)

Explanatory note

Analysis of the results of the exam showed that the "Chemical organization of the cell" for graduates is problematic. To solve this problem, it is necessary to develop persistent skills for completing tasks used in the exam. The proposed tests contain that biology teachers can use to practice these skills, both in the classroom and in individual consultations in preparation for the exam.

The tests are based on the materials of KIMs (they are marked with an asterisk) and from additional literature. Tasks from additional literature are distinguished by their informativeness, therefore they can be used as an additional source of knowledge.

The following literature was used to compile the tests:

KIMs in biology for 2011 and 2011. V. N. Frosin, V. I. Sivoglazov “Preparing for the unified state exam. General Biology. Bustard. Moscow. 2011

Topic 1:"Inorganic substances of the cell"

Part A tasks.

1.* The bodies of animate and inanimate nature are similar in set

2) chemical elements

3) nucleic acids

4) enzymes

2.* Magnesium is an essential component of molecules

2) chlorophyll

3) hemoglobin

3.* What role do potassium and sodium ions play in the cell?

1) are biocatalysts

2) participate in the excitation

3) provide transport of gases

4) promote the movement of substances across the membrane

4. What is the ratio of sodium and potassium ions in animal cells and in their environment - intercellular fluid and blood?

1) there is more sodium in the cell than outside, potassium, on the contrary, more outside than in the cell

2) there is as much sodium outside as there is potassium inside the cell

3) there is less sodium in the cell than outside, and, on the contrary, more potassium in the cell than outside

5. Name the chemical element that in the form of an ion in large quantities is part of the cytoplasm of cells, where it is significantly larger than in the intercellular fluid and is directly involved in the formation of a constant difference in electrical potentials on opposite sides of the outer plasma membrane

1) H 4) C 7) Ca 10) Na

2) O 5)S 8)Mg 11) Zn

3) N 6) Fe 9) K 12) P

6. Name the chemical element that is part of the inorganic component of bone tissue and shells of mollusks, takes part in muscle contraction and blood coagulation, is an intermediary in the transmission of an information signal from the outer plasma membrane to the cell cytoplasm

1) H 4) C 7) Ca 10) Na

2) O 5) S Mg 11) Zn

3) N 6) Fe 9) K 12) P

7. Name the chemical element that is part of chlorophyll and is necessary for the assembly of small and large subunits of the ribosome into a single structure, activates some enzymes

1) H 4) C 7) Ca 10) Na

2) O 5) S Mg 11) Zn

3) N 6) Fe 9) K 12) P

8. Name the chemical element that is part of hemoglobin and myoglobin, where it participates in the addition of oxygen, and is also part of one of the mitochondrial proteins of the respiratory chain that carries electrons during cellular respiration.

1) H 4) C 7) Ca 10) Na

2) O 5) S Mg 11) Zn

3) N 6) Fe 9) K 12) P

9. Indicate the group of chemical elements, the content of which in the cell is 98% in total,

10. Name the liquid that, in terms of salt composition, is closest to the blood plasma of terrestrial vertebrates

1) 0.9% NaCl solution

2) sea water

3) fresh water

11. Name the organic compounds that are contained in the cell in the largest amount (in% of wet weight)

1) carbohydrates

4) nucleic acids

12. Name the organic compounds that are contained in the cell in the smallest amount (in% of wet weight)

1) carbohydrates

4) nucleic acids

13. * A significant part of the cell is water, which

1) forms a division spindle

2) forms protein globules

3) dissolves fats

4) gives the cell elasticity

14. What is the main feature of the structure of the water molecule, which determines the specific properties and biological role of water

1) small size

2) polarity of the molecule

3) high mobility

15.*Water is a good solvent because

1) its molecules have mutual attraction

2) its molecules are polar

3) it heats up and cools down slowly

4) she is a catalyst

16.* The water in the cell performs the function

1) catalytic

2) solvent

3) structural

4) information

1) communication with neighboring cells

2) growth and development

3) the ability to share

4) volume and elasticity

18. All of the above anions, except for one, are part of the salts and are the most important anions for the life of the cell. Indicate the “extra” anion among them.

Right answers

Part B tasks.

Choose three correct answers from six.

1) What are the functions of water in a cell?

A) performs an energy function

B) provides cell elasticity

B) protect the contents of the cell

D) participates in thermoregulation

D) participates in the hydrolysis of substances

E) provides the movement of organelles.

Answer: B, D, D

2) * Water in the cage plays the role

A) internal environment

B) structural

B) regulatory

D) humoral

D) a universal source of energy

E) universal solvent

Answer: A, B, E.

Topic 2:"Biological polymers - proteins".

Part A tasks.

Choose one correct answer.

one*. Proteins are classified as biopolymers because they

1) are very diverse

2) play an important role in the cell

3) consist of repeatedly repeating links

4) have a large molecular weight

2*. The monomers of protein molecules are

1) nucleotides

2) amino acids

3) monosaccharides

3*. Polypeptides are formed as a result of interaction

1) 1) nitrogenous bases

2) 2) lipids

3) 3) carbohydrates

4) 4) amino acids

4*. The type of number and order of amino acids depends on

1) 1) sequence of RNA triplets

2) 2) the primary structure of proteins

3) 3) hydrophobicity of fat molecules

4) 4) hydrophilicity of monosaccharides

5*. The cells of all living organisms contain

1) 1) hemoglobin

2) 2) protein

3) 3) chitin

4) 4) fiber

6*. The sequence of amino acids in protein molecules is determined

1) 1) the arrangement of triplets in the DNA molecule

2) 2) a structural feature of the ribosome

3) 3) a set of ribosomes in the polysome

4) 4) a feature of the structure of T-RNA

7*. Reversible denaturation of protein molecules occurs

1) 1) violation of its primary structure

2) 2) the formation of hydrogen bonds

3) 3) violation of its tertiary structure

4) 4) formation of peptide bonds

eight*. The ability of protein molecules to form compounds with other substances determines their function.

1) 1) transport

2) 2) energy

3) 3) contractile

4) 4) excretory

nine*. What is the function of contractile proteins in animals?

1) transport

2) signal

3) motor

4) catalytic

ten*. Organic substances that accelerate metabolic processes -

1) amino acids

2) monosaccharides

3) enzymes

eleven*. What is the function of proteins in a cell?

1) protective

2) enzymatic

3) information

The chemical composition of living organisms can be expressed in two forms - atomic and molecular.

Atomic (elemental) composition characterizes the ratio of atoms of elements included in living organisms.
Molecular (material) composition reflects the ratio of molecules of substances.

Elementary Composition

According to the relative content of the elements that make up living organisms, they are divided into three groups.

Groups of elements according to their content in living organisms

Macronutrients make up the bulk of the percentage composition of living organisms.

The content of some chemical elements in natural objects

Chemical elements that are part of living organisms and at the same time perform biological functions are called biogenic. Even those of them that are contained in cells in negligible amounts cannot be replaced by anything and are absolutely necessary for life. Basically, these are macro- and microelements. The physiological role of most trace elements is not disclosed.

The role of biogenic elements in living organisms

Molecular composition

Chemical elements are part of cells in the form of ions and molecules of inorganic and organic substances. The most important inorganic substances in the cell are water and mineral salts, the most important organic substances are carbohydrates, lipids, proteins and nucleic acids.

The content of chemicals in the cell

inorganic substances

Water

Water- the predominant substance of all living organisms. It has unique properties due to structural features: water molecules have the form of a dipole and hydrogen bonds form between them. The average water content in the cells of most living organisms is about 70%. Water in the cell is present in two forms: free(95% of all cell water) and related(4–5% bound to proteins). The functions of water are presented in the table.

Functions of water

mineral salts

mineral salts In an aqueous solution, cells dissociate into cations and anions.
The most important cations are K +, Ca 2+, Mg 2+, Na +, NH 4+,
The most important anions are Cl - , SO 4 2- , HPO 4 2- , H 2 PO 4 - , HCO 3 - , NO 3 - .
Essential is not only the concentration, but also the ratio of individual ions in the cell.
The functions of minerals are presented in the table.

Functions of minerals

In addition, hydrochloric acid is part of the gastric juice of animals and humans, accelerating the process of digestion of food proteins. Residues of sulfuric acid contribute to the removal of foreign substances from the body. Sodium and potassium salts of nitrous and phosphoric acids, calcium salt of sulfuric acid are important components of the mineral nutrition of plants, they are applied to the soil as fertilizers.

organic matter

Polymer- a multi-link chain in which a link is any relatively simple substance - a monomer. Polymers are linear and branched, homopolymers(all monomers are the same - glucose residues in starch) and heteropolymers(different monomers - amino acid residues in proteins), regular(the group of monomers in the polymer is periodically repeated) and irregular(there is no visible repeatability of monomer units in molecules).
biological polymers- These are polymers that are part of the cells of living organisms and their metabolic products. Biopolymers are proteins, nucleic acids, polysaccharides. The properties of biopolymers depend on the number, composition, and arrangement of their constituent monomers. Changing the composition and sequence of monomers in the polymer structure leads to a significant number of variants of biological macromolecules.

Carbohydrates

Carbohydrates- organic compounds consisting of one or more molecules of simple sugars. The content of carbohydrates in animal cells is 1–5%, and in some plant cells it reaches 70%.
There are three groups of carbohydrates: monosaccharides, oligosaccharides(consist of 2-10 molecules of simple sugars), polysaccharides(consist of more than 10 sugar molecules). Combined with lipids and proteins, carbohydrates form glycolipids and glycoproteins.

Characterization of carbohydrates

The functions of carbohydrates are presented in the table.

Functions of carbohydrates

Lipids

Lipids- fats and fat-like organic compounds, practically insoluble in water. Their content in different cells varies greatly from 2–3 (in the cells of plant seeds) to 50–90% (in the adipose tissue of animals). Chemically, lipids are usually esters of fatty acids and a number of alcohols.

They are divided into several classes. Most common in nature neutral fats, waxes, phospholipids, steroids. Most lipids contain fatty acids, the molecules of which contain a hydrophobic long-chain hydrocarbon "tail" and a hydrophilic carboxyl group.
Fats- esters of trihydric alcohol glycerol and three molecules of fatty acids. Wax are esters of polyhydric alcohols and fatty acids. Phospholipids have a phosphoric acid residue instead of a fatty acid residue in the molecule. Steroids do not contain fatty acids and have a special structure. Also, living organisms are characterized lipoproteins- compounds of lipids with proteins without the formation of covalent bonds and glycolipids- lipids, in which, in addition to the fatty acid residue, one or more sugar molecules are contained.
Lipid functions are presented in the table.

Functions of lipids

Squirrels

Proteins are the most numerous and most diverse class of organic compounds in the cell. Squirrels are biological heteropolymers whose monomers are amino acids.

By chemical composition amino acids- these are compounds containing one carboxyl group (-COOH) and one amine group (-NH 2), associated with one carbon atom to which the side chain is attached - some radical R. It is the radical that gives the amino acid its unique properties.
Only 20 amino acids are involved in the formation of proteins. They're called fundamental, or main: alanine, methionine, valine, proline, leucine, isoleucine, tryptophan, phenylalanine, asparagine, glutamine, serine, glycine, tyrosine, threonine, cysteine, arginine, histidine, lysine, aspartic and glutamic acids. Some of the amino acids are not synthesized in the organisms of animals and humans and must be supplied with plant foods. They are called essential: arginine, valine, histidine, isoleucine, leucine, lysine, methionine, threonine, tryptophan, phenylalanine.
Amino acids bond with each other covalently peptide bonds, form peptides of various lengths
A peptide (amide) is a covalent bond formed by the carboxyl group of one amino acid and the amino group of another.
Proteins are high molecular weight polypeptides, which include from one hundred to several thousand amino acids.
There are 4 levels of protein organization:

Levels of protein organization

The configuration of a protein depends on the sequence of amino acids, but it can also be influenced by the specific conditions in which the protein is located.
The loss of a protein molecule of its structural organization is called denaturation.

Denaturation may be reversible and irreversible. With reversible denaturation, the quaternary, tertiary and secondary structures are destroyed, but due to the preservation of the primary structure, when normal conditions return, it is possible renaturation protein - restoration of normal (native) conformation. Irreversible denaturation destroys the primary structure of the protein. Denaturation can be caused by high temperature (above 45°C), dehydration, ionizing radiation, and other factors. A change in the conformation (spatial structure) of a protein molecule underlies a number of protein functions (signaling, antigenic properties, etc.).
According to the chemical composition, simple and complex proteins are distinguished. Simple proteins consist only of amino acids (fibrillar proteins, antibodies - immunoglobulins). Complex proteins contain a protein part and a non-protein part prosthetic groups. Distinguish lipoproteins(contain lipids) glycoproteins(carbohydrates), phosphoproteins(one or more phosphate groups), metalloproteins(various metals), nucleoproteins(nucleic acids). Prosthetic groups usually play an important role in the performance of a protein's biological function.
The functions of proteins are presented in the table.

Functions of proteins

Enzymes. Protein enzymes catalyze chemical reactions in the body. These reactions, due to energy reasons, either do not occur in the body at all, or proceed too slowly.
The enzymatic reaction can be expressed by the general equation:
E+S → → E+P,
where the substrate (S) reacts reversibly with the enzyme (E) to form an enzyme-substrate complex (ES), which then decomposes to form the reaction product (P). The enzyme is not part of the final products of the reaction.
The enzyme molecule has active center, consisting of two sections - sorption(responsible for the binding of the enzyme to the substrate molecule) and catalytic(responsible for the flow of catalysis itself). During the reaction, the enzyme binds the substrate, successively changes its configuration, forming a number of intermediate molecules that ultimately give the reaction products.
The difference between enzymes and inorganic catalysts:
1. One enzyme catalyzes only one type of reaction.
2. The activity of enzymes is limited by a rather narrow temperature range (usually 35-45 o C).
3. Enzymes are active at certain pH values ​​(most in a slightly alkaline environment).

Nucleic acids

Mononucleotides. A mononucleotide consists of one nitrogenous base - purine(adenine - A, guanine - G) or pyrimidine(cytosine - C, thymine - T, uracil - U), pentose sugars (ribose or deoxyribose) and 1–3 phosphoric acid residues.
Depending on the number of phosphate groups, mono-, di- and triphosphates of nucleotides are distinguished, for example, adenosine monophosphate - AMP, guanosine diphosphate - GDP, uridine triphosphate - UTP, thymidine triphosphate - TTP, etc.
The functions of mononucleotides are presented in the table.

Functions of mononucleotides

Polynucleotides. Nucleic acids (polynucleotides)- polymers, the monomers of which are nucleotides. There are two types of nucleic acids: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
Nucleotides of DNA and RNA consist of the following components:

1. nitrogenous base(in DNA: adenine, guanine, cytosine and thymine; in RNA: adenine, guanine, cytosine and uracil).
2. Pentose sugar(in DNA - deoxyribose, in RNA - ribose).
3. rest of phosphoric acid.

DNA (deoxyribonucleic acid)- a linear polymer consisting of four types of monomers: nucleotides A, T, G and C, linked to each other by a covalent bond through phosphoric acid residues.

The DNA molecule consists of two spirally twisted chains (double helix). In this case, two hydrogen bonds are formed between adenine and thymine, and three between guanine and cytosine. These base pairs are called complementary. In the DNA molecule, they are always located opposite each other. The strands in the DNA molecule are oppositely directed. The spatial structure of the DNA molecule was established in 1953 by D. Watson and F. Crick.

By binding to proteins, the DNA molecule forms a chromosome. Chromosome- a complex of one DNA molecule with proteins. DNA molecules of eukaryotic organisms (fungi, plants and animals) are linear, open, associated with proteins, forming chromosomes. In prokaryotes (bacteria), DNA is closed in a ring, not associated with proteins, and does not form a linear chromosome.

DNA function: storage, transmission and reproduction in a number of generations of genetic information. DNA determines which proteins need to be synthesized and in what quantities.
RNA (ribonucleic acids) unlike DNA, they contain ribose instead of deoxyribose, and uracil instead of thymine. RNA usually has only one strand, which is shorter than DNA strands. Double-stranded RNAs are found in some viruses.
There are 3 types of RNA.

Types of RNA

RNA functions: participation in protein biosynthesis.
DNA self-replication. DNA molecules have the ability not inherent in any other molecule - the ability to duplicate. The process of duplication of DNA molecules is called replication.

Replication is based on the principle of complementarity - the formation of hydrogen bonds between nucleotides A and T, G and C.
Replication is carried out by DNA polymerase enzymes. Under their influence, the chains of the DNA molecules are separated in a small segment of the molecule. Child chains are completed on the chain of the parent molecule. Then a new segment unwinds, and the replication cycle repeats.
As a result, daughter DNA molecules are formed, which are no different from each other and from the parent molecule. In the process of cell division, daughter DNA molecules are distributed between the resulting cells. This is how information is passed from generation to generation.
Under the influence of various environmental factors (ultraviolet radiation, various chemicals), the DNA molecule can be damaged. Chain breaks, erroneous substitutions of nitrogenous bases of nucleotides, etc. occur. In addition, changes in DNA can occur spontaneously, for example, as a result of recombination- exchange of DNA fragments. The changes that have occurred in hereditary information are also transmitted to offspring.
In some cases, DNA molecules are able to "correct" the changes that occur in its chains. This ability is called reparations. Proteins are involved in the restoration of the original DNA structure, which recognize the altered sections of DNA and remove them from the chain, thereby restoring the correct nucleotide sequence, stitching the restored fragment with the rest of the DNA molecule.
Comparative characteristics of DNA and RNA are presented in the table.

Comparative characteristics of DNA and RNA

Cell structure Cell theory

Formation of the cell theory:

• Robert Hooke in 1665 discovered cells in a section of cork and was the first to use the term cell.
• Anthony van Leeuwenhoek discovered unicellular organisms.
• Matthias Schleiden in 1838 and Thomas Schwann in 1839 formulated the main provisions of the cell theory. However, they erroneously believed that cells arise from the primary non-cellular substance.
• Rudolf Virchow proved in 1858 that all cells are formed from other cells by cell division.

The main provisions of the cell theory:

1. The cage is structural unit all living things. All living organisms are made up of cells (viruses are an exception).
2. The cage is functional unit all living things. The cell shows the whole range of vital functions.
3. The cage is unit of development all living things. New cells are formed only as a result of the division of the original (mother) cell.
4. The cage is genetic unit all living things. The chromosomes of a cell contain information about the development of the whole organism.
5. The cells of all organisms are similar in chemical composition, structure and function.

Types of cell organization

Among living organisms, only viruses do not have a cellular structure. All other organisms are represented by cellular life forms. There are two types of cellular organization: prokaryotic and eukaryotic. Prokaryotes include bacteria and cyanobacteria (blue-green), while eukaryotes include plants, fungi and animals.

prokaryotic cells are relatively simple. They do not have a nucleus, the location of DNA in the cytoplasm is called a nucleoid, the only DNA molecule is circular and is not associated with proteins, cells are smaller than eukaryotic cells, the cell wall includes a glycopeptide - murein, there are no membrane organelles, their functions are performed by invaginations of the plasma membrane (mesosomes), ribosomes are small, microtubules are absent, so the cytoplasm is immobile, and cilia and flagella have a special structure.

eukaryotic cells have a nucleus in which chromosomes are located - linear DNA molecules associated with proteins; various membrane organelles are located in the cytoplasm.
plant cells differ in the presence of a thick cellulose cell wall, plastids, and a large central vacuole that shifts the nucleus to the periphery. The cell center of higher plants does not contain centrioles. The storage carbohydrate is starch.
mushroom cells have a cell wall containing chitin, there is a central vacuole in the cytoplasm, and there are no plastids. Only some fungi have a centriole in the cell center. The main reserve carbohydrate is glycogen.
Animal cells do not have a cell wall, do not contain plastids and a central vacuole, a centriole is characteristic of the cell center. The storage carbohydrate is glycogen.
Depending on the number of cells that make up organisms, they are divided into unicellular and multicellular. unicellular organisms consist of a single cell that performs the functions of an integral organism. All prokaryotes are unicellular, as well as protozoa, some green algae and fungi. Body multicellular organisms consists of many cells combined into tissues, organs and organ systems. The cells of a multicellular organism are specialized to perform a certain function and can exist outside the body only in a microenvironment close to physiological (for example, under tissue culture conditions). Cells in a multicellular organism vary in size, shape, structure, and function. Despite individual characteristics, all cells are built according to a single plan and have many common features.

Characterization of eukaryotic cell structures

Main differences between prokaryotic and eukaryotic cells

Video lesson 2: Structure, properties and functions of organic compounds The concept of biopolymers

Lecture: The chemical composition of the cell. Macro- and microelements. The relationship of the structure and functions of inorganic and organic substances

The chemical composition of the cell

It has been found that about 80 chemical elements are constantly contained in the cells of living organisms in the form of insoluble compounds and ions. All of them are divided into 2 large groups according to their concentration:

macronutrients, the content of which is not lower than 0.01%;

trace elements - the concentration of which is less than 0.01%.

In any cell, the content of microelements is less than 1%, macroelements, respectively, more than 99%.

Macronutrients:

Sodium, potassium and chlorine - provide many biological processes - turgor (internal cellular pressure), the appearance of nerve electrical impulses.

Nitrogen, oxygen, hydrogen, carbon. These are the main components of the cell.

Phosphorus and sulfur are important components of peptides (proteins) and nucleic acids.

Calcium is the basis of any skeletal formations - teeth, bones, shells, cell walls. Also involved in muscle contraction and blood clotting.

Magnesium is a component of chlorophyll. Participates in the synthesis of proteins.

Iron is a component of hemoglobin, is involved in photosynthesis, determines the performance of enzymes.

trace elements contained in very low concentrations, are important for physiological processes:

Zinc is a component of insulin;

Copper - participates in photosynthesis and respiration;

Cobalt is a component of vitamin B12;

Iodine is involved in the regulation of metabolism. It is an important component of thyroid hormones;

Fluorine is a component of tooth enamel.

Imbalance in the concentration of micro and macro elements leads to metabolic disorders, the development of chronic diseases. Lack of calcium - the cause of rickets, iron - anemia, nitrogen - deficiency of proteins, iodine - a decrease in the intensity of metabolic processes.

Consider the relationship of organic and inorganic substances in the cell, their structure and functions.

Cells contain a huge number of micro and macromolecules belonging to different chemical classes.

Inorganic substances of the cell

Water. Of the total mass of a living organism, it makes up the largest percentage - 50-90% and takes part in almost all life processes:

thermoregulation;

capillary processes, as it is a universal polar solvent, affects the properties of the interstitial fluid, the intensity of metabolism. In relation to water, all chemical compounds are divided into hydrophilic (soluble) and lipophilic (soluble in fats).

The intensity of metabolism depends on its concentration in the cell - the more water, the faster the processes occur. Loss of 12% of water by the human body - requires restoration under the supervision of a doctor, with a loss of 20% - death occurs.

mineral salts. Contained in living systems in dissolved form (having dissociated into ions) and undissolved. Dissolved salts are involved in:

transport of substances across the membrane. Metal cations provide a "potassium-sodium pump" by changing the osmotic pressure of the cell. Because of this, water with substances dissolved in it rushes into the cell or leaves it, carrying away unnecessary ones;

the formation of nerve impulses of an electrochemical nature;

muscle contraction;

blood clotting;

are part of proteins;

phosphate ion is a component of nucleic acids and ATP;

carbonate ion - maintains Ph in the cytoplasm.

Insoluble salts in the form of whole molecules form the structures of shells, shells, bones, teeth.

The organic matter of the cell

Common feature of organic substances- the presence of a carbon skeletal chain. These are biopolymers and small molecules of a simple structure.

The main classes found in living organisms:

Carbohydrates. There are various types of them in cells - simple sugars and insoluble polymers (cellulose). In percentage terms, their share in the dry matter of plants is up to 80%, animals - 20%. They play an important role in the life support of cells:

Fructose and glucose (monosugar) - are quickly absorbed by the body, are included in metabolism, and are a source of energy.

Ribose and deoxyribose (monosugar) are one of the three main components of DNA and RNA.

Lactose (refers to disaccharides) - synthesized by the animal body, is part of the milk of mammals.

Sucrose (disaccharide) - a source of energy, is formed in plants.

Maltose (disaccharide) - provides seed germination.

Also, simple sugars perform other functions: signaling, protective, transport.
Polymeric carbohydrates are water-soluble glycogen, as well as insoluble cellulose, chitin, and starch. They play an important role in metabolism, carry out structural, storage, protective functions.

lipids or fats. They are insoluble in water, but mix well with each other and dissolve in non-polar liquids (not containing oxygen, for example, kerosene or cyclic hydrocarbons are non-polar solvents). Lipids are needed in the body to provide it with energy - when they are oxidized, energy and water are formed. Fats are very energy efficient - with the help of 39 kJ per gram released during oxidation, you can lift a load weighing 4 tons to a height of 1 m. Also, fat provides a protective and heat-insulating function - in animals, its thick layer helps to keep warm in the cold season. Fat-like substances protect the feathers of waterfowl from getting wet, provide a healthy shiny appearance and elasticity of animal fur, and perform an integumentary function on plant leaves. Some hormones have a lipid structure. Fats form the basis of the structure of membranes.

Proteins or proteins are heteropolymers of biogenic structure. They consist of amino acids, the structural units of which are: amino group, radical, and carboxyl group. The properties of amino acids and their differences from each other determine the radicals. Due to amphoteric properties, they can form bonds with each other. A protein can be made up of a few or hundreds of amino acids. In total, the structure of proteins includes 20 amino acids, their combinations determine the variety of forms and properties of proteins. About a dozen amino acids are essential - they are not synthesized in the animal body and their intake is provided by plant foods. In the gastrointestinal tract, proteins are broken down into individual monomers used for the synthesis of their own proteins.

Structural features of proteins:

primary structure - amino acid chain;

secondary - a chain twisted into a spiral, where hydrogen bonds are formed between the turns;

tertiary - a spiral or several of them, folded into a globule and connected by weak bonds;

quaternary does not exist in all proteins. These are several globules connected by non-covalent bonds.

The strength of structures can be broken and then restored, while the protein temporarily loses its characteristic properties and biological activity. Irreversible is only the destruction of the primary structure.

Proteins perform many functions in the cell:

acceleration of chemical reactions (enzymatic or catalytic function, each of which is responsible for a specific single reaction);
transport - the transfer of ions, oxygen, fatty acids through cell membranes;

protective- such blood proteins as fibrin and fibrinogen are present in the blood plasma in an inactive form, at the site of wounds under the action of oxygen form blood clots. Antibodies provide immunity.

structural– peptides are partly or are the basis of cell membranes, tendons and other connective tissues, hair, wool, hooves and nails, wings and outer coverings. Actin and myosin provide contractile activity of muscles;

regulatory- proteins-hormones provide humoral regulation;
energy - during the absence of nutrients, the body begins to break down its own proteins, disrupting the process of its own vital activity. That is why, after a long hunger, the body cannot always recover without medical help.

Nucleic acids. There are 2 of them - DNA and RNA. RNA is of several types - informational, transport, ribosomal. Opened by the Swiss F. Fischer at the end of the 19th century.

DNA is deoxyribonucleic acid. Contained in the nucleus, plastids and mitochondria. Structurally, it is a linear polymer that forms a double helix of complementary nucleotide chains. The idea of ​​its spatial structure was created in 1953 by the Americans D. Watson and F. Crick.

Its monomeric units are nucleotides, which have a fundamentally common structure of:

phosphate groups;

deoxyribose;

nitrogenous base (belonging to the purine group - adenine, guanine, pyrimidine - thymine and cytosine.)

In the structure of a polymer molecule, nucleotides are combined in pairs and complementary, which is due to the different number of hydrogen bonds: adenine + thymine - two, guanine + cytosine - three hydrogen bonds.

The order of nucleotides encodes the structural amino acid sequences of protein molecules. A mutation is a change in the order of nucleotides, since protein molecules of a different structure will be encoded.

RNA is ribonucleic acid. Structural features of its difference from DNA are:

instead of thymine nucleotide - uracil;

ribose instead of deoxyribose.

Transfer RNA - this is a polymer chain, which is folded in the plane in the form of a clover leaf, its main function is to deliver amino acids to ribosomes.

Matrix (information) RNA is constantly formed in the nucleus, complementary to any section of DNA. This is a structural matrix; on the basis of its structure, a protein molecule will be assembled on the ribosome. Of the total content of RNA molecules, this type is 5%.

Ribosomal- Responsible for the process of composing a protein molecule. Synthesized in the nucleolus. It is 85% in the cage.

ATP is adenosine triphosphate. This is a nucleotide containing:

3 residues of phosphoric acid;

As a result of cascade chemical processes, respiration is synthesized in mitochondria. The main function is energy, one chemical bond in it contains almost as much energy as is obtained by oxidizing 1 g of fat.

Carbohydrates, or saccharides, are one of the main groups of organic compounds. They are part of the cells of all living organisms. The main function of carbohydrates is energy (during the breakdown and oxidation of carbohydrate molecules, energy is released, which ensures the vital activity of the body). With an excess of carbohydrates, they accumulate in the cell as reserve substances (starch, glycogen) and, if necessary, are used by the body as an energy source. Carbohydrates are also used as a building material.

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The chemical composition of the cell

(preparation for the exam)

Carbohydrates, or saccharides, are one of the main groups of organic compounds. They are part of the cells of all living organisms.

The main function of carbohydrates is energy (during the breakdown and oxidation of carbohydrate molecules, energy is released, which ensures the vital activity of the body). With an excess of carbohydrates, they accumulate in the cell as reserve substances (starch, glycogen) and, if necessary, are used by the body as an energy source. Carbohydrates are also used as a building material.

General Carbohydrate Formula

Cn (H 2 O ) m

Carbohydrates are made up of carbon, hydrogen and oxygen.

Other elements may also be included in the composition of carbohydrate derivatives.

Water-soluble carbohydrates.Monosaccharides and disaccharides

Example:

Of the monosaccharides, ribose, deoxyribose, glucose, fructose, and galactose are of greatest importance for living organisms.

Glucose is the main source of energy for cellular respiration.

Fructose is an integral part of the nectar of flowers and fruit juices.

Ribose and deoxyribose are structural elements of nucleotides, which are monomers of nucleic acids (RNA and DNA).
Disaccharides are formed by combining two molecules of monosaccharides and are close in their properties to monosaccharides. For example, both are highly soluble in water and have a sweet taste.

Example:

Sucrose (cane sugar), maltose (malt sugar), lactose (milk sugar) are disaccharides formed as a result of the fusion of two monosaccharide molecules:

sucrose (glucose + fructose) - the main product of photosynthesis transported in plants.

Lactose (glucose + galactose) - is part of the milk of mammals.

Maltose (glucose + glucose) - energy source in germinating seeds.

Functions of soluble carbohydrates: transport, protective, signal, energy.

Water insoluble polysaccharides

Polysaccharides are made up of a large number of monosaccharides. With an increase in the amount of monomers, the solubility of polysaccharides decreases and the sweet taste disappears.

Example:

Polymeric carbohydrates: starch, glycogen, cellulose, chitin.

Functions of polymeric carbohydrates: structural, storage, energy, protective.
Starch consists of branched spiralized molecules that form reserve substances in plant tissues.

Cellulose is an important structural component of the cell walls of fungi and plants.

Cellulose is insoluble in water and has high strength.

Chitin consists of amino derivatives of glucose and is part of the cell walls of some fungi and forms the external skeleton of arthropods.
Glycogen - storage substance of an animal cell.

Complex polysaccharides are also known that perform structural functions in the supporting tissues of animals (they are part of the intercellular substance of the skin, tendons, cartilage, giving them strength and elasticity).

Lipids - an extensive group of fat-like substances (esters of fatty acids and trihydric alcohol glycerol), insoluble in water. Lipids include fats, waxes, phospholipids, and steroids (lipids that do not contain fatty acids).

Lipids are made up of hydrogen, oxygen and carbon atoms.

Lipids are present in all cells without exception, but their content in different cells varies greatly (from 2-3 to 50-90%).

Lipids can form complex compounds with other classes of substances, such as proteins (lipoproteins) and carbohydrates (glycolipids).

Lipid functions:

• Reserve - fats are the main form of storage of lipids in the cell.
• Energy - half of the energy consumed by the cells of vertebrates at rest is formed as a result of the oxidation of fats (when oxidized, they provide more than twice as much energy as carbohydrates).
• Fats are used and how water source (when 1 g of fat is oxidized, more than 1 g of water is formed).
• Protective - subcutaneous fat layer protects the body from mechanical damage.
• Structural Phospholipids are part of cell membranes.
• Thermal insulation- subcutaneous fat helps to keep warm.
• electrical insulating- myelin, secreted by Schwann cells (form sheaths of nerve fibers), isolates some neurons, which many times accelerates the transmission of nerve impulses.
• Hormonal (regulatory) ) - adrenal hormone - cortisone and sex hormones (progesterone and testosterone) are steroids ().
• Lubricating Waxes cover the skin, wool, feathers and protect them from water. The leaves of many plants are covered with a wax coating; wax is used in the construction of honeycombs.

Proteins (proteins, polypeptides ) are the most numerous, most diverse and of paramount importance biopolymers. The composition of protein molecules includes atoms of carbon, oxygen, hydrogen, nitrogen and sometimes sulfur, phosphorus and iron.

Protein monomers are amino acids that (having in its composition carboxyl and amino groups)possess the properties of an acid and a base (amphoteric).

Due to this, amino acids can combine with each other (their number in one molecule can reach several hundred). In this regard, protein molecules are large and are calledmacromolecules.

Structure of a protein molecule

The structure of a protein molecule is understood as its amino acid composition, the sequence of monomers and the degree of twisting of the protein molecule.

In protein molecules, there are only 20 types of different amino acids, and a huge variety of proteins is created due to their various combinations.

• The sequence of amino acids in a polypeptide chain isprimary structure of a protein(it is unique to any protein and determines its shape, properties and functions). The primary structure of a protein is unique to any type of protein and determines the shape of its molecule, its properties and functions.
• A long protein molecule folds and first takes the form of a spiral as a result of the formation of hydrogen bonds between the -CO and -NH groups of different amino acid residues of the polypeptide chain (between the carbon of the carboxyl group of one amino acid and the nitrogen of the amino group of another amino acid). This spiral isprotein secondary structure.
• Tertiary structure of a protein- three-dimensional spatial “packing” of the polypeptide chain in the form globules (ball). The strength of the tertiary structure is provided by a variety of bonds that arise between amino acid radicals (hydrophobic, hydrogen, ionic and disulfide S-S bonds).
• Some proteins (such as human hemoglobin) havequaternary structure.It arises as a result of the combination of several macromolecules with a tertiary structure into a complex complex. The quaternary structure is held together by fragile ionic, hydrogen, and hydrophobic bonds.

The structure of proteins can be disturbed (subjected to denaturation ) when heated, treated with certain chemicals, irradiation, etc. With a weak effect, only the quaternary structure breaks down, with a stronger effect, the tertiary, and then the secondary, and the protein remains in the form of a polypeptide chain. As a result of denaturation, the protein loses its ability to perform its function.

Violation of the quaternary, tertiary and secondary structures is reversible. This process is called renaturation.

The destruction of the primary structure is irreversible.

In addition to simple proteins, consisting only of amino acids, there are also complex proteins, which may include carbohydrates ( glycoproteins), fats (lipoproteins ), nucleic acids ( nucleoproteins), etc.

Functions of proteins

• Catalytic (enzymatic) function.Special proteins - enzymes - capable of accelerating biochemical reactions in the cell by tens and hundreds of millions of times. Each enzyme speeds up one and only one reaction. Enzymes contain vitamins.

• Structural (building) function- one of the main functions of proteins (proteins are part of cell membranes; keratin protein forms hair and nails; collagen and elastin proteins - cartilage and tendons).

• transport function- proteins provide active transport of ions through cell membranes (transport proteins in the outer membrane of cells), transport of oxygen and carbon dioxide (blood hemoglobin and myoglobin in muscles), transport of fatty acids (blood serum proteins contribute to the transport of lipids and fatty acids, various biologically active substances ).

• Signal function. The reception of signals from the external environment and the transmission of information to the cell occurs due to proteins built into the membrane that can change their tertiary structure in response to the action of environmental factors.
• Contractile (motor) function- provided by contractile proteins - actin and myosin (due to contractile proteins, cilia and flagella move in protozoa, chromosomes move during cell division, muscles contract in multicellular organisms, other types of movement in living organisms improve.

• Protective function- Antibodies provide immune defense of the body; fibrinogen and fibrin protect the body from blood loss by forming a blood clot.

• Regulatory functioninherent in proteins hormones (not all hormones are proteins!). They maintain constant concentrations of substances in the blood and cells, participate in growth, reproduction and other vital processes (for example, insulin regulates blood sugar).
• energy function- during prolonged starvation, proteins can be used as an additional source of energy after carbohydrates and fats are used up (with the complete breakdown of 1 g of protein to end products, 17.6 kJ of energy is released). Amino acids released during the breakdown of protein molecules are used to build new proteins.

Nucleic acids(from lat. nucleus - nucleus) were first discovered in 1868 in the nuclei of leukocytes by the Swiss scientist F. Miescher. Later it was found that nucleic acids are contained in all cells (in the cytoplasm, nucleus and in all organelles of the cell).

Primary structure of nucleic acid molecules

Nucleic acids are the largest of the molecules formed by living organisms. They are biopolymers consisting of monomers - nucleotides.

Pay attention!

Each nucleotide is made up ofnitrogenous base, five-carbon sugar (pentose) and phosphate group (phosphoric acid residue).

Depending on the type of five-carbon sugar (pentose), two types of nucleic acids are distinguished:

• deoxyribonucleic acids(abbreviated DNA) - the DNA molecule contains a five-carbon sugar - deoxyribose.
• ribonucleic acids(abbreviated as RNA) - the RNA molecule contains a five-carbon sugar - ribose.

There are differences in the nitrogenous bases that make up the nucleotides of DNA and RNA:

DNA nucleotides T - thymine
RNA nucleotides : A - adenine, G - guanine, C - cytosine, U - uracil

Secondary structure of DNA and RNA molecules

Secondary structure is the shape of nucleic acid molecules.

The spatial structure of the DNA molecule was modeled by American scientists James Watson and Francis Crick in 1953.

Deoxyribonucleic acid (DNA)- consists of two helically twisted chains, which are connected to each other along the entire length by hydrogen bonds. Such a structure (inherent only in DNA molecules) is calleddouble helix.

Ribonucleic acid (RNA)- linear polymer, consisting of one chain of nucleotides.

The exception is viruses that have single-stranded DNA and double-stranded RNA.

More details about DNA and RNA will be discussed in the section "Storage and transmission of genetic information. Genetic code".

Adenosine triphosphoric acid - ATP

Nucleotides are the structural basis for a number of organic substances important for life, for example, macroergic compounds.
The universal source of energy in all cells is ATP - adenosine triphosphoric acid or adenosine triphosphate.
ATP is found in the cytoplasm, mitochondria, plastids and cell nuclei and is the most common and universal source of energy for most biochemical reactions occurring in the cell.
ATP provides energy for all cell functions: mechanical work, biosynthesis of substances, division, etc. Average content ATP in a cell is about 0.05% of its mass, but in those cells where the costs ATP are large (for example, in liver cells, striated muscles), its content can reach up to 0.5%.

The structure of ATP

ATP is a nucleotide consisting of a nitrogenous base - adenine, a ribose carbohydrate and three phosphoric acid residues, two of which store a large amount of energy.

The bond between phosphoric acid residues is calledmacroergic(it is denoted by the symbol ~), since when it breaks, almost 4 times more energy is released than when other chemical bonds are split.

ATP - unstable structure and when separating one residue of phosphoric acid, ATP converted to adenosine diphosphate ( ADP ) releasing 40 kJ of energy.

Other nucleotide derivatives

Hydrogen carriers constitute a special group of nucleotide derivatives. Molecular and atomic hydrogen has a high chemical activity and is released or absorbed during various biochemical processes. One of the most widely used hydrogen carriers isnicotinamide dinucleotide phosphate(NADP).

NADP molecule capable of attaching two atoms or one molecule of free hydrogen, turning into a reduced form NADP ⋅ H2 . In this form, hydrogen can be used in various biochemical reactions.
Nucleotides can also take part in the regulation of oxidative processes in the cell.

vitamins

Vitamins (from lat. vita - life) - complex bioorganic compounds, absolutely necessary in small quantities for the normal functioning of living organisms. Vitamins differ from other organic substances in that they are not used as an energy source or building material. Some vitamins organisms can synthesize themselves (for example, bacteria are able to synthesize almost all vitamins), other vitamins enter the body with food.
Vitamins are usually denoted by letters of the Latin alphabet. The modern classification of vitamins is based on their ability to dissolve in water and fats (they are divided into two groups:water soluble(B 1, B 2, B 5, B 6, B 12, PP , C ) and fat-soluble(A , D , E , K )).
Vitamins are involved in almost all biochemical and physiological processes that together make up the metabolism. Both deficiency and excess of vitamins can lead to serious impairment of many physiological functions in the body.

Minerals in the cell are in the form of salts in the solid state, or dissociated into ions.
inorganic ions represented by cations and anions mineral salts.

Example:

Cations: K +, Na +, Ca 2+, Mg 2+, NH +4

Anions: Cl -, H 2 PO -4, HPO 2-4, HCO -3, NO -3, SO -4, PO 3-4, CO 2-3

Together with soluble organic compounds, inorganic ions provide stable performanceosmotic pressure.

The concentration of cations and anions in the cell and in its environment is different. Cations predominate inside the cell K + and large negative organic ions, there are always more ions in pericellular fluids Na+ and Cl −. As a result, apotential differencebetween the contents of the cell and its environment, providing such important processes as irritability and transmission of excitation along a nerve or muscle.

As components of the body's buffer systems, ions determine their properties - the ability to maintain pH at a constant level (close to neutral), despite the fact that acidic and alkaline products are continuously formed in the process of metabolism.

Example:

anions phosphoric acid(HPO 2-4 and H 2 PO -4) create a phosphate buffer system in mammals that maintains the pH of the intracellular fluid within 6.9 - 7.4.
Carbonic acid and its anions(H 2 CO 3 and NO −3) create a bicarbonate buffer system and maintain the pH of the extracellular medium (blood plasma) at the level of 7.4.

Compounds of nitrogen, phosphorus, calcium and other inorganic substances are used for the synthesis of organic molecules (amino acids, proteins, nucleic acids, etc.).

Example:

Some metal ions (Mg, Ca, Fe, Zn, Cu, Mn, Mo, Br, Co) are components of many enzymes, hormones and vitamins or activate them.

Potassium - ensures the functioning of cell membranes, maintains acid-base balance, affects the activity and concentration of magnesium.

Na + and K ions + contribute to the conduction of nerve impulses and cell excitability. These ions are also part of the sodium-potassium pump (active transport) and create a transmembrane potential of cells (provides selective permeability of the cell membrane, which is achieved due to the difference in ion concentrations Na+ and K +: more inside the cell K +, more outside Na+).

Ions play a key role in the regulation of muscle contraction calcium (Ca 2+). Myofibrils have the ability to interact with ATP and contract only if there are certain concentrations of calcium ions in the medium. Calcium ions are also essential for the blood clotting process.

Iron is part of the hemoglobin in the blood.

Nitrogen included in proteins. All the most important parts of cells (cytoplasm, nucleus, shell, etc.) are built from protein molecules.

Phosphorus is part of nucleic acids; ensuring the normal growth of bone and dental tissues.

With a lack of minerals, the most important processes of cell vital activity are disrupted.

Test

1. Select examples of the functions of proteins that they carry out at the cellular level of life.

1) provide transport of ions through the membrane

2) are part of the hair, feathers

3) form the skin

4) antibodies bind antigens

5) store oxygen in the muscles

6) ensure the work of the division spindle

2. Select the features of RNA.

1) found in ribosomes and nucleolus

2) capable of replication

3) consists of one chain

4) is contained in chromosomes

5) set of nucleotides ATHC

6) a set of nucleotides AGCU

3. What are the functions of lipids in the body of animals?

1) enzymatic

2) storage

3) energy

4) structural

5) contractile

6) receptor

4. What are the functions of carbohydrates in the body of animals?

1) catalytic

2) structural

3) storage

4) hormonal

5) contractile

6) energy

5. Proteins, unlike nucleic acids,

1) participate in the formation of the plasma membrane

2) are part of the chromosomes

3) participate in humoral regulation

4) carry out the transport function

5) perform a protective function

6) transfer hereditary information from the nucleus to the ribosome

6 Which of the following proteins cannot be found inside a muscle cell?

1) actin

2) hemoglobin

3) fibrinogen

4) ATPase

5) RNA polymerase

6) trypsin

7. Select the features of the structure of protein molecules.

1) are made up of fatty acids

2) consist of amino acids

3) the monomers of the molecule are held by peptide bonds

4) consist of monomers of the same structure

5) are polyhydric alcohols

6) the quaternary structure of molecules consists of several globules

8. Choose three functions that are unique to proteins.

1) energy

2) catalytic

3) motor

4) transport

5) structural

6) storage

9. All of the following chemical elements, except for two, are organogens. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated in response.

1) hydrogen

2) nitrogen

3) magnesium

4) chlorine

5) oxygen

10 . Choose THREE functions of DNA in a cell

1) an intermediary in the transfer of hereditary information

2) storage of hereditary information

3) amino acid coding

4) template for mRNA synthesis

5) regulatory

6) chromosome structuring

11 DNA molecule

1) a polymer whose monomer is a nucleotide

2) a polymer whose monomer is an amino acid

3) double-chain polymer

4) single chain polymer

5) contains hereditary information

6) performs an energy function in the cell

12. What are the characteristics of a DNA molecule?

1) consists of one polypeptide strand

2) consists of two polynucleotide strands twisted into a spiral

3) has a nucleotide containing uracil

4) has a nucleotide containing thymine

5) preserves hereditary information

6) transfers information about the structure of the protein from the nucleus to the ribosome

13 . How is an mRNA molecule different from DNA?

1) transfers hereditary information from the nucleus to the ribosome

2) the composition of nucleotides includes residues of nitrogenous bases, carbohydrate and phosphoric acid

3) consists of one polynucleotide strand

4) consists of two interconnected polynucleotide strands

5) it contains the carbohydrate ribose and the nitrogenous base uracil

6) it contains the carbohydrate deoxyribose and the nitrogenous base thymine

14. All of the features below, except for two, are functions of lipids. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated in the table.

1) storage

2) hormonal

3) enzymatic

4) carrier of hereditary information

5) energy

15. All of the following features, except for two, can be used to describe the importance of proteins in the human and animal body. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated in response.

1) serve as the main building material

2) are broken down in the intestine to glycerol and fatty acids

3) are formed from amino acids

4) converted to glycogen in the liver

5) as enzymes accelerate chemical reactions

16 .All of the features listed below, except for two, can be used to describe the DNA molecule. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated in the table.

1) consists of two polynucleotide chains twisted into a spiral

2) transfers information to the site of protein synthesis

3) in complex with proteins builds the body of the ribosome

4) capable of self-doubling

5) in complex with proteins forms chromosomes

17 . All but two of the features listed below can be used to describe the insulin molecule. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated in the table

1) consists of amino acids

2) adrenal hormone

3) a catalyst for many chemical reactions

4) pancreatic hormone

5) a substance of protein nature

18 All but two of the following features can be used to describe egg white albumin. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated in the table.

1) consists of amino acids

2) digestive enzyme

3) denatures reversibly when the egg is boiled

4) monomers are linked by peptide bonds

5) the molecule forms primary, secondary and tertiary structures

19 All but two of the features listed below can be used to describe the starch molecule. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated in the table.

1) consists of one chain

2) highly soluble in water

3) in complex with proteins forms a cell wall

4) undergoes hydrolysis

5) is a reserve substance in muscle cells

20. Select the cell organelles containing hereditary information.

1) core

2) lysosomes

3) Golgi apparatus

4) ribosomes

5) mitochondria

6) chloroplasts

21Task 4 Choose structures that are characteristic only for a plant cell.

1) mitochondria

2) chloroplasts

3) cell wall

4) ribosomes

5) vacuoles with cell sap

6) Golgi apparatus

22 Viruses, unlike bacteria,

1) have a cell wall

2) adapt to the environment

3) consist only of nucleic acid and protein

4) reproduce vegetatively

5) do not have their own metabolism

23. The similar structure of plant and animal cells is proof

1) their relationship

2) common origin of organisms of all kingdoms

3) the origin of plants from animals

4) complication of organisms in the process of evolution

5) the unity of the organic world

6) diversity of organisms

24 What are the functions of the Golgi complex?

1) synthesizes organic substances from inorganic

2) breaks down biopolymers to monomers

3) accumulates proteins, lipids, carbohydrates synthesized in the cell

4) provides packaging and removal of substances from the cell

5) oxidizes organic substances to inorganic

6) participates in the formation of lysosomes

25 The autotrophs are

1) spore plants

2) mold fungi

3) unicellular algae

4) chemotrophic bacteria

5) viruses

6) most protozoa

26 Which of the following organelles are membranous?

1) lysosomes

2) centrioles

3) ribosomes

4) microtubules

5) vacuoles

6) leukoplasts

27 Select the provisions of the synthetic theory of evolution.

1) Species really exist in nature and are formed for a long time.

2) Mutations and combinations of genes serve as material for evolution.

3) The driving forces of evolution are the mutation process, population waves, combinative variability.

4) In nature, there are various types of struggle for existence between organisms.

5) Natural selection is the guiding factor of evolution.

6) Natural selection preserves some individuals and destroys others.

28 What substances make up the cell membrane?

1) lipids

2) chlorophyll

3) RNA

4) carbohydrates

5) proteins

6) DNA

29. In which of the following cell organelles do matrix synthesis reactions occur?

1) centrioles

2) lysosomes

3) Golgi apparatus

4) ribosomes

5) mitochondria

6) chloroplasts

30. Eukaryotes include

1) common amoeba

2) yeast

4) cholera vibrio

5) E. coli

6) human immunodeficiency virus

31. Prokaryotic cells are different from eukaryotic cells

1) the presence of a nucleoid in the cytoplasm

2) the presence of ribosomes in the cytoplasm

3) ATP synthesis in mitochondria

4) the presence of the endoplasmic reticulum

5) the absence of a morphologically distinct nucleus

6) the presence of invaginations of the plasma membrane, performing the function of membrane organelles

32. What are the features of the structure and functions of mitochondria

1) the inner membrane forms grana

2) are part of the nucleus

3) synthesize their own proteins

4) participate in the oxidation of organic substances to and

5) provide glucose synthesis

6) are the site of ATP synthesis

33. Which of the following functions is performed by the plasma membrane of a cell? Write down the numbers in ascending order.

1) participates in the synthesis of lipids

2) carries out active transport of substances

3) participates in the process of phagocytosis

4) participates in the process of pinocytosis

5) is a site for the synthesis of membrane proteins

6) coordinates the process of cell division

34. What are the features of the structure and functions of ribosomes? Write down the numbers in ascending order.

1) have one membrane

2) consist of DNA molecules

3) break down organic matter

4) consist of large and small particles

5) participate in the process of protein biosynthesis

6) consist of RNA and protein

35. Which of the listed organelles are membranous? Write down the numbers in ascending order.

1) lysosomes

2) centrioles

3) ribosomes

4) vacuoles

5) leucoplasts

6) microtubules

36. All the signs below, except for two, can be used to describe the functions of the cytoplasm. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated in response.

1) the internal environment in which the organelles are located

2) glucose synthesis

3) the relationship of metabolic processes

4) oxidation of organic substances to inorganic

5) communication between cell organelles

37. All the features below, except for two, can be used to characterize the general properties of mitochondria and chloroplasts. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated in the table.

1) form lysosomes

2) are two-membrane

3) are semi-autonomous organelles

4) participate in the synthesis of ATP

5) form a division spindle

38All of the features listed below, except for two, can be used to describe the cell organoid shown in the figure. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated in the table in the table.

1) is found in plant and animal cells

2) characteristic of prokaryotic cells

3) participates in the formation of lysosomes

4) forms secretory vesicles

5) two-membrane organoid

39All of the features listed below, except for two, can be used to describe the cell organoid shown in the figure. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated in the table.

1) single-membrane organoid

2) consists of cristae and chromatin

3) contains circular DNA

4) synthesizes its own protein

5) capable of division

40. All the signs listed below, except for two, can be used to describe the cell organoid shown in the figure. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated in the table in the table.

1) single-membrane organoid

2) contains fragments of ribosomes

3) the shell is riddled with pores

4) contains DNA molecules

5) contains mitochondria

41 All of the features listed below, except for two, can be used to describe the cell shown in the figure. Identify two features that "fall out" from the general list; write down the numbers under which they are indicated in the table.

1) there is a cell membrane

2) the cell wall is made up of chitin

3) the hereditary apparatus is enclosed in a ring chromosome

4) reserve substance - glycogen

5) the cell is capable of photosynthesis

42All of the features listed below, except for two, can be used to describe the cell depicted in the figure. Identify two features that "fall out" from the general list; write down the numbers under which they are indicated in the table

1) there is a cell membrane

2) there is a Golgi apparatus

3) there are several linear chromosomes

4) have ribosomes

5) there is a cell wall

to prepare for the exam in biology on the topic

"Chemical organization of the cell"

Explanatory note

The analysis of the results of the exam showed that the topic "Chemical organization of the cell" is problematic for graduates. To solve this problem, it is necessary to develop persistent skills for completing tasks used in the exam. The proposed tests contain tasks that biology teachers can use to practice these skills, both in the classroom and at individual consultations in preparation for the exam.

The tests are based on the materials of KIMs (they are marked with an asterisk) and from additional literature. Tasks from additional literature are distinguished by their informativeness, therefore they can be used as an additional source of knowledge.

Topic 1:"Inorganic substances of the cell"

Part A tasks.

Choose one correct answer.

1.* The bodies of animate and inanimate nature are similar in set

2) chemical elements

3) nucleic acids

4) enzymes

2.* Magnesium is an essential component of molecules

2) chlorophyll

3) hemoglobin

3.* What role do potassium and sodium ions play in the cell?

1) are biocatalysts

2) participate in the excitation

3) provide transport of gases

4) promote the movement of substances across the membrane

4. What is the ratio of sodium and potassium ions in animal cells and in their environment - intercellular fluid and blood?

1) there is more sodium in the cell than outside, potassium, on the contrary, more outside than in the cell

2) there is as much sodium outside as there is potassium inside the cell

3) there is less sodium in the cell than outside, and, on the contrary, more potassium in the cell than outside

5. Name the chemical element that in the form of an ion in large quantities is part of the cytoplasm of cells, where it is significantly larger than in the intercellular fluid and is directly involved in the formation of a constant difference in electrical potentials on opposite sides of the outer plasma membrane

1) H 4) C 7) Ca 10) Na

2) O 5)S 8)Mg 11) Zn

3) N 6) Fe 9) K 12) P

6. Name the chemical element that is part of the inorganic component of bone tissue and shells of mollusks, takes part in muscle contraction and blood coagulation, is an intermediary in the transmission of an information signal from the outer plasma membrane to the cell cytoplasm

1) H 4) C 7) Ca 10) Na

2) O 5) S 8) Mg 11) Zn

3) N 6) Fe 9) K 12) P

7. Name the chemical element that is part of chlorophyll and is necessary for the assembly of small and large subunits of the ribosome into a single structure, activates some enzymes

1) H 4) C 7) Ca 10) Na

2) O 5) S 8) Mg 11) Zn

3) N 6) Fe 9) K 12) P

8. Name the chemical element that is part of hemoglobin and myoglobin, where it participates in the addition of oxygen, and is also part of one of the mitochondrial proteins of the respiratory chain that carries electrons during cellular respiration.

1) H 4) C 7) Ca 10) Na

2) O 5) S 8) Mg 11) Zn

3) N 6) Fe 9) K 12) P

9. Indicate the group of chemical elements, the content of which in the cell is 98% in total,

10. Name the liquid that, in terms of salt composition, is closest to the blood plasma of terrestrial vertebrates

1) 0.9% NaCl solution

2) sea water

3) fresh water

11. Name the organic compounds that are contained in the cell in the largest amount (in% of wet weight)

1) carbohydrates

4) nucleic acids

12. Name the organic compounds that are contained in the cell in the smallest amount (in% of wet weight)

1) carbohydrates

4) nucleic acids

13. * A significant part of the cell is water, which

1) forms a division spindle

2) forms protein globules

3) dissolves fats

4) gives the cell elasticity

14. What is the main feature of the structure of the water molecule, which determines the specific properties and biological role of water

1) small size

2) polarity of the molecule

3) high mobility

15.*Water is a good solvent because

1) its molecules have mutual attraction

2) its molecules are polar

3) it heats up and cools down slowly

4) she is a catalyst

16.* The water in the cell performs the function

1) catalytic

2) solvent

3) structural

4) information

1) communication with neighboring cells

2) growth and development

3) the ability to share

4) volume and elasticity

18. All of the above anions, except for one, are part of the salts and are the most important anions for the life of the cell. Indicate the “extra” anion among them.

4) H 2 RO 4 -

Right answers

Part B tasks.

Choose three correct answers from six.

1) What are the functions of water in a cell?

A) performs an energy function

B) provides cell elasticity

B) protect the contents of the cell

D) participates in thermoregulation

D) participates in the hydrolysis of substances

E) provides the movement of organelles.

Answer: B, D, D

2) * Water in the cage plays the role

A) internal environment

B) structural

B) regulatory

D) humoral

D) a universal source of energy

E) universal solvent

Answer: A, B, E.

Topic 2:"Biological polymers - proteins".

Part A tasks.

Choose one correct answer.

one*. Proteins are classified as biopolymers because they:

1) are very diverse

2) play an important role in the cell

3) consist of repeatedly repeating links

4) have a large molecular weight

2*. The monomers of protein molecules are

1) nucleotides

2) amino acids

3) monosaccharides

3*. Polypeptides are formed as a result of interaction

1) nitrogenous bases

2) lipids

3) carbohydrates

4) amino acids

4*. The type of number and order of amino acids depends on

1) sequence of RNA triplets

2) the primary structure of proteins

3) hydrophobicity of fat molecules

4) hydrophilicity of monosaccharides

5*. The cells of all living organisms contain

1) hemoglobin

2. 4) fiber

6*. The sequence of amino acids in protein molecules is determined

1) the arrangement of triplets in the DNA molecule

2) a structural feature of the ribosome

3) a set of ribosomes in a polysome

4) a feature of the structure of T-RNA

7*. Reversible denaturation of protein molecules occurs

1) violation of its primary structure

2) formation of hydrogen bonds

3) violation of its tertiary structure

4) formation of peptide bonds

eight*. The ability of protein molecules to form compounds with other substances determines their function.

1) transport

2) energy

3) contractile

4) excretory

nine*. What is the function of contractile proteins in animals?

1) transport

2) signal

3) motor

4) catalytic

ten*. Organic substances that accelerate metabolic processes -

1) amino acids

2) monosaccharides

3) enzymes

eleven*. What is the function of proteins in a cell?

1) protective

2) enzymatic

3) information

4) contractile

Part B tasks.

Choose three correct answers from six.

one*. What are the features of the structure and properties of protein molecules?

A) has primary, secondary, tertiary, quaternary structures.

B) have the form of a single spiral

B) amino acid monomers

D) monomers-nucleotides

D) capable of replication

E) capable of denaturation

Answers: A, B, E.

Part C tasks.

Give a complete detailed answer.

one*. Enzymes lose their activity when radiation levels rise.

Explain why.

Answer: All enzymes are proteins. Under the action of radiation, the structure changes

protein-enzyme, its denaturation occurs.