Slide 3

• Enzymes
• Protective
• Antibiotics
• Structural
• Motor
• Protective
• Toxins
• Spares
• Receptor
• Hormones
• Catalytic
• Transport
• Contractives

Slide 4

• The functions of proteins in the cells of living organisms are more diverse than the functions of other biopolymers - polysaccharides and DNA. Thus, enzyme proteins catalyze the occurrence of biochemical reactions and play an important role in metabolism. Cytoskeleton of eukaryotes (Fig. 1) Some proteins perform a structural or mechanical function, forming a cytoskeleton (Fig. 1) that maintains the shape of cells. Proteins also play an important role in cell signaling systems, the immune response, and the cell cycle.

Slide 5

Structural function

• The structural function of proteins is that proteins participate in the formation of almost all cell organelles, largely determining their structure (shape);
• form the cytoskeleton, which gives shape to cells and many organelles and provides the mechanical shape of a number of tissues;
• are part of the intercellular substance, which largely determines the structure of tissues and the shape of the body of animals. Structural proteins include:

Collagen-actin

Elastin-myosin

Keratin-tubulin

Slide 6

Catalytic function (enzymatic)

• The most well-known role of proteins in the body is the catalysis of various chemical reactions.
• Enzymes are a group of proteins that have specific catalytic properties, that is, each enzyme catalyzes one or more similar reactions, accelerating them.
• Example: 2Н202 → 2Н20 + 02
• In the presence of iron salts (catalyst), this reaction proceeds somewhat faster.
• Catalase enzyme in 1 sec. breaks down up to 100 thousand H2O2 molecules.
• Molecules that attach to an enzyme and change as a result of the reaction are called substrates.
• The mass of the enzyme is much greater than the mass of the substrate. The part of the enzyme that attaches substrates contains catalytic amino acids is called the active site of the enzyme.

Slide 7

Motor function

• Muscle contraction is a process during which chemical energy stored in the form of high-energy pyrophosphate bonds in ATP molecules is converted into mechanical work. Direct participants in the contraction process are two proteins - actin and myosin.
• Special contractile proteins (actin and myosin) are involved in all types of cell and organism movement: the formation of pseudopodia, the flickering of cilia and the beating of flagella in protozoa, muscle contraction in multicellular animals, the movement of leaves in plants, etc.

Slide 8

Transport function

• The transport function of proteins is the participation of proteins in the transfer of substances into and out of cells, in their movements within cells, as well as in their transport by blood and other fluids throughout the body.
• There are different types of transport that are carried out using proteins.
  • Transport of substances across the cell membrane
  • Transport of substances within the cell
  • Transport of substances throughout the body
• For example, blood hemoglobin carries oxygen

Slide 9

Protective function

• Protect the body from invasion of foreign organisms and damage
• Antibodies block foreign proteins
• For example, fibrinogen and prothrombin provide blood clotting

Slide 10

• In response to the penetration of foreign proteins or microorganisms (antigens) into the body, special proteins are formed - antibodies that can bind and neutralize them.

Slide 11

Energy function

• Energy function - proteins serve as one of the energy sources in the cell.
• When 1 g of protein breaks down into final products, 17.6 kJ of energy is released.
• First, proteins break down into amino acids, and then into final products:

Carbon dioxide,

Ammonia.

• But proteins are used extremely rarely as a source of energy.

Slide 12

Receptor function

• Receptor proteins are protein molecules built into the membrane that can change their structure in response to the addition of a certain chemical substance.

Slide 13

Immune function (antibiotics)

• The moment pathogens - viruses or bacteria - enter the body, specialized organs begin to produce special proteins - antibodies that bind and neutralize the pathogens. The peculiarity of the immune system is that, due to antibodies, it can fight almost any type of pathogen.
• Interferons also belong to the protective proteins of the immune system. These proteins are produced by cells infected with viruses. Their effect on neighboring cells provides antiviral resistance by blocking the multiplication of viruses or the assembly of viral particles in target cells. Interferons also have other mechanisms of action, for example, they affect the activity of lymphocytes and other cells of the immune system.

Slide 14

Toxins

• Toxins, toxic substances of natural origin. Typically, toxins include high-molecular compounds (proteins, polypeptides, etc.), when they enter the body, antibodies are produced.
• According to the target of action, toxins are divided into
  • -Hematic poisons are poisons that affect the blood.
  • -Neurotoxins are poisons that affect the nervous system and brain.
  • -Myoxic poisons are poisons that damage muscles.
  • -Hemotoxins are toxins that damage blood vessels and cause bleeding.
  • -Hemolytic toxins are toxins that damage red blood cells.
  • -Nephrotoxins are toxins that damage the kidneys.
  • -Cardiotoxins are toxins that damage the heart.
  • -Necrotoxins are toxins that destroy tissues, causing their death (necrosis).
• Consider plant poisons:
• Phallotoxins and amatoxins are found in various species: toadstool, stinking fly agaric, spring fly agaric.
• Toadstool white (Fig. 1) is a deadly poisonous mushroom that contains the poisons amanitine and virosine. For humans, the lethal dose of a-amanitin is 5-7 mg, phalloidin
• 20-30 mg (one mushroom contains on average up to 10 mg of phalloidin, 8 mg of L-amanitin and 5 mg of B-amanitin). In case of poisoning, death occurs.

Slide 15

Contractile function

• Proteins - participate in the contraction of muscle fibers.
• Contractile function. Many protein substances are involved in the act of muscle contraction and relaxation. However, the main role in these vital processes is played by actin and myosin, specific proteins of muscle tissue. The contractile function is inherent not only in muscle proteins, but also in cytoskeletal proteins, which ensures the finest processes of cell life (chromosome divergence during mitosis).
• Actin and myosin are muscle proteins

Slide 16

Hormonal function

• Hormonal function. Metabolism in the body is regulated by various mechanisms. In this regulation, an important place is occupied by hormones synthesized not only in the endocrine glands, but also in many other cells of the body (see below). A number of hormones are represented by proteins or polypeptides, for example, hormones of the pituitary gland, pancreas, etc. Some hormones are derivatives of amino acids.

Slide 17

Nutritional function (reserve)

• Nutritional (reserve) function. This function is performed by so-called reserve proteins, which are sources of nutrition for the fetus, for example egg proteins (ovalbumin). The main protein in milk (casein) also has a primarily nutritional function. A number of other proteins are used in the body as a source of amino acids, which in turn are precursors of biologically active substances that regulate metabolic processes.
• Milk casein Egg albumin

Slide 18

Regulatory function

• Some proteins are hormones. Hormones are biologically active substances released into the blood by various glands that take part in the regulation of metabolic processes.
• The hormone insulin regulates the level of carbohydrates in the blood.

Slide 19

Thank you for your attention

Completed by: Fedotova V.

View all slides

1 of 19

Presentation on the topic: Presentation Functions of Proteins

Slide no. 1

Slide description:

Slide no. 2

Slide description:

Proteins Proteins (proteins, polypeptides) are high-molecular organic substances consisting of alpha-amino acids connected in a chain by a peptide bond. Proteins are an important part of the nutrition of animals and humans, since their bodies cannot synthesize all the necessary amino acids and some of them come from protein foods. During the digestion process, enzymes break down consumed proteins into amino acids, which are used in the biosynthesis of body proteins or undergo further breakdown to produce energy.

Slide no. 3

Slide description:

Slide no. 4

Slide description:

Functions of proteins The functions of proteins in the cells of living organisms are more diverse than the functions of other biopolymers - polysaccharides and DNA. Thus, enzyme proteins catalyze the occurrence of biochemical reactions and play an important role in metabolism. Cytoskeleton of eukaryotes (Fig. 1) Some proteins perform a structural or mechanical function, forming a cytoskeleton (Fig. 1) that maintains the shape of cells. Proteins also play an important role in cell signaling systems, the immune response, and the cell cycle.

Slide no. 5

Slide description:

Structural function. The structural function of proteins is that proteins participate in the formation of almost all cell organelles, largely determining their structure (shape); form the cytoskeleton, which gives shape to cells and many organelles and provides the mechanical shape of a number of tissues; are part of the intercellular substance, which largely determines the structure of tissues and the shape of the body of animals. Structural proteins include: - collagen - actin - elastin - myosin - keratin - tubulin

Slide no. 6

Slide description:

Catalytic function. (enzymatic) The most well-known role of proteins in the body is the catalysis of various chemical reactions. Enzymes are a group of proteins that have specific catalytic properties, that is, each enzyme catalyzes one or more similar reactions, accelerating them. Example: 2H202 → 2H20 + 02 In the presence of iron salts (catalyst), this reaction proceeds somewhat faster. Catalase enzyme in 1 sec. breaks down up to 100 thousand H2O2 molecules. Molecules that attach to an enzyme and change as a result of the reaction are called substrates. The mass of the enzyme is much greater than the mass of the substrate. The part of the enzyme that attaches substrates contains catalytic amino acids is called the active site of the enzyme.

Slide no. 7

Slide description:

Motor function. Muscle contraction is a process during which chemical energy stored in the form of high-energy pyrophosphate bonds in ATP molecules is converted into mechanical work. Direct participants in the contraction process are two proteins - actin and myosin. Special contractile proteins (actin and myosin) are involved in all types of cell and organism movement: the formation of pseudopodia, the flickering of cilia and the beating of flagella in protozoa, muscle contraction in multicellular animals, the movement of leaves in plants, etc.

Slide no. 8

Slide description:

Transport function. The transport function of proteins is the participation of proteins in the transfer of substances into and out of cells, in their movements within cells, as well as in their transport by blood and other fluids throughout the body. There are different types of transport that are carried out using proteins.

Slide no. 9

Slide description:

Slide no. 10

Slide description:

Slide no. 11

Slide description:

Energy function. Energy function - proteins serve as one of the energy sources in the cell. When 1 g of protein breaks down into final products, 17.6 kJ of energy is released. First, proteins break down into amino acids, and then into final products: -water, -carbon dioxide, -ammonia. But proteins are used extremely rarely as a source of energy.

Slide no. 12

Slide description:

Slide no. 13

Slide description:

Immune function. (antibiotics) The moment pathogens - viruses or bacteria - enter the body, specialized organs begin to produce special proteins - antibodies that bind and neutralize the pathogens. The peculiarity of the immune system is that, due to antibodies, it can fight almost any type of pathogen. Interferons also belong to the protective proteins of the immune system. These proteins are produced by cells infected with viruses. Their effect on neighboring cells provides antiviral resistance by blocking the multiplication of viruses or the assembly of viral particles in target cells. Interferons also have other mechanisms of action, for example, they affect the activity of lymphocytes and other cells of the immune system.

Slide no. 14

Slide description:

Toxins Toxins, toxic substances of natural origin. Typically, toxins include high-molecular compounds (proteins, polypeptides, etc.), when they enter the body, antibodies are produced. According to the target of action, toxins are divided into - Hematic poisons - poisons affecting the blood. -Neurotoxins are poisons that affect the nervous system and brain. -Myoxic poisons are poisons that damage muscles. -Hemotoxins are toxins that damage blood vessels and cause bleeding. -Hemolytic toxins are toxins that damage red blood cells. -Nephrotoxins are toxins that damage the kidneys. -Cardiotoxins are toxins that damage the heart. -Necrotoxins are toxins that destroy tissues, causing them to die (necrosis). Let's consider plant poisons: Phallotoxins and amatoxins are found in various types: toadstool, stinking fly agaric, spring fly agaric. Toadstool white (Fig. 1) is a deadly poisonous mushroom that contains the poisons amanitine and virosine. For humans, the lethal dose of a-amanitin is 5-7 mg, phalloidin 20-30 mg (one mushroom on average contains up to 10 mg of phalloidin, 8 mg of L-amanitin and 5 mg of B-amanitin). In case of poisoning, death occurs.

Slide description:

Hormonal function. Hormonal function. Metabolism in the body is regulated by various mechanisms. In this regulation, an important place is occupied by hormones synthesized not only in the endocrine glands, but also in many other cells of the body (see below). A number of hormones are represented by proteins or polypeptides, for example, hormones of the pituitary gland, pancreas, etc. Some hormones are derivatives of amino acids.

Slide no. 17

Slide description:

Nutritional function. (reserve) Nutritional (reserve) function. This function is performed by so-called reserve proteins, which are sources of nutrition for the fetus, for example egg proteins (ovalbumin). The main protein in milk (casein) also has a primarily nutritional function. A number of other proteins are used in the body as a source of amino acids, which in turn are precursors of biologically active substances that regulate metabolic processes. Milk casein Egg albumin

Sections: Biology

Class: 10

The purpose of the lesson: using knowledge about the structure and properties of proteins to expand understanding of the functions of proteins through creative and research activities ( Annex 1 . Slide No. 2).

Tasks(Slide No. 3)

Educational:

To expand knowledge about proteins as natural polymers, about the diversity of their functions in relation to their structure and properties.

Educational:

1. Develop students’ thinking and ability to establish cause-and-effect relationships by studying the properties and functions of proteins as an example.
2. Develop practical skills in performing cytological experiments to establish the role of enzyme proteins.
3. Develop the ability to draw conclusions based on practical work, develop the ability to independently obtain information from additional information sources (information competence).
4. Develop the ability to structure material.
5. Develop the ability to analyze your activities.

Educational:

1. Develop the ability to work in a group
2. To cultivate students’ accuracy when performing and preparing practical work and notes in notebooks.

Lesson type: combined with the use of research activities.

Technologies: test, ICT, problem-based learning.

Methods: partially search, verbal, visual, research.

Equipment: presentation “Functions of Proteins”, computer with a multimedia projector, laboratory equipment for research on the topic “Enzymatic function of proteins”: petri dishes, hydrogen peroxide, pipette, pieces of boiled and raw meat, boiled and raw potatoes, river sand.

Methodological support:

1. Handout – text “Squirrels” ( Appendix 2 ), instruction card for laboratory work “Enzymatic function of proteins” ( Appendix 3 ), a task to establish correspondence between proteins and their functions ( Appendix 4 ). Annex 1 Microsoft PowerPoint presentation "Protein Functions" (
2. ) – (POWER POINT).
3. Possibility of presenting unique information materials in multimedia form ( Appendix 5 ).

DURING THE CLASSES

1. Organizational start of the lesson(greeting, checking readiness for work, psychological mood for the lesson) (Slide No. 4).

Parable

“Once upon a time there lived a wise man who knew everything. One man wanted to prove that the sage does not know everything. Holding a butterfly in his palms, he asked: “Tell me, sage, which butterfly is in my hands: dead or alive?” And he himself thinks: “If the living one says, I will kill her; the dead one will say, I will release her.” The sage, after thinking, replied: “Everything is in your hands.”
It is in our hands today to create an atmosphere in the classroom in which everyone will feel comfortable.
The epigraph of our lesson will be the words of A. Einstein “The joy of seeing and understanding is the greatest gift of nature” (Slide No. 5).

2. Motivation

Exercise: analyze the pie chart (Slide No. 6) and answer the questions:

1) What is the chemical composition of the cell?
2) What organic substances are there more in the cell?
3) What does the similarity in the chemical composition of cells indicate?

“Life is a way of existence of protein bodies” (F. Engels) (Slide No. 7).
Chemists have not studied any substance for as long as proteins before they managed to unravel their structure. More than two hundred years have passed from the first steps towards understanding the composition of a protein to deciphering its structure.
Any biological object, from viruses to humans, consists mainly of proteins (in terms of dry matter),
therefore, it is very important to know the structure, properties and functions of these compounds.

3. Personal significance of the material being studied

A person must consume 100 g of protein per day, otherwise protein starvation will develop.
(Slide No. 8) Lack of protein in the diet causes a slowdown in growth and development in children, and in adults - profound changes in the liver, disruption of the endocrine glands, changes in hormonal levels, deterioration in the absorption of nutrients, problems with the heart muscle, deterioration in memory and performance .
In the 70s, deaths were reported in people following long-term low-calorie diets with a severe lack of protein. This happened due to serious disturbances in the activity of the heart muscle. Protein deficiency reduces the body's resistance to infections. In addition, protein deficiency is often accompanied by vitamin deficiency B12, A, D, K, and so on, which also affects health.

Question for students:“What personal meaning do these facts have for each of you?”

4. Goal setting

Exercise: Establish a correspondence between proteins and their functions ( Appendix 4 , Slide No. 9).

Proteins: Functions

A. Keratin 1. Construction
B. Hemoglobin 2. Storage
V. Actin 3. Protective
D. Antibodies 4. Motor
D. Myosin 5. Transport
E. Fibrinogen 6. Enzymatic
G. Collagen 7. Regulatory
Z. Albumin
I. Catalase
K. Pepsin
L. Insulin

Why can't you complete this task? (answer: lack of knowledge)

Statement of a problematic question. The composition of the cell includes proteins, fats, carbohydrates, nucleic acids, water, minerals, but none of the substances performs such specific functions as proteins. Is this fair?
Students set goals and objectives for their work in this lesson.

5. Updating knowledge

Tasks:

1. Work with slides No. 10-15 and talk about the following questions:

1) What are polymers?
2) Using the diagram, answer with evidence which polymers proteins belong to?
3) The structure of the protein monomer.
4) Characteristics of the structural organization of the protein.

2. Working with the text “Squirrels”(Slide No. 16).

Fill in the missing terms and words into the text.

1) Protein contains the following elements___,___,____,___,____. 2) Proteins – _______________,___________________________ polymers,
whose monomers are ____________________. 3) Natural proteins contain ______ amino acids, ___ of which are essential, i.e. are synthesized in the body and do not necessarily enter the body with food. 4) Protein monomers consist of ___________,_________________.________________. 5) All protein monomers include ___________, ________________, and differ in __________. 6) Denaturation is the process of changing the native structure of a protein.

6. Learning new material

The properties and functions of a protein are determined by its structure, structure and diversity, so even small defects in its structure have serious consequences.
The hereditary disease sickle cell anemia is due to the fact that during the synthesis of hemoglobin, which consists of approximately 600 amino acid residues, two of them are changed to others. This leads to disruption of hemoglobin function: the red blood cells of patients acquire a sickle shape and lose the ability to carry normal oxygen (Slide No. 17).
This is an example of the relationship between structure and function of macromolecules.

Working with slide number 18

The result of this work will be a table, which we will fill out as we work.

Functions of proteins

Let's remember: “What is hereditary information stored in the cell nucleus” (imagine a logical chain: trait – substance – reaction – protein – enzyme). Pavlov called enzymes “stimulants of life and the first act of life activity.”
Among the many functions of proteins, the enzymatic function occupies a special place.

The science of enzymes is called enzymology, and enzymes are called enzymes.
Expression by I.P. Pavlov’s “Not all proteins are enzymes, but all enzymes are proteins” emphasizes their chemical organization.
Next, the teacher explains the structure and mechanism of action of the enzyme.

What explains the accelerating effect of enzymes?

(Slide 19) Each enzyme has an active center - a specific group of amino acid residues. In the active center, the enzyme combines with the substrate (the substance that is to be converted). The shape of the active center and the substrate fit each other like a key to a lock.

The process of enzyme action can be divided into three stages:

1. The enzyme recognizes the substrate and binds to it.
2. An active complex consisting of an enzyme and a substrate is formed.
3. Separation of a product as a result of an enzymatic reaction.

Properties of enzymes (graph analysis) (Slides 20-23)

Research assignment(Work in groups):

Laboratory work "Enzymatic breakdown of hydrogen peroxide in body tissues"(Appendix 3 )

Target: develop knowledge about the role of enzymes in cells, consolidate the ability to conduct experiments and explain the results of the work.

Equipment: fresh 3% hydrogen peroxide solution, a stand with test tubes, plant tissue (pieces of raw and boiled potatoes) and animal tissue (pieces of raw and boiled meat), pipettes, sand.

Progress:

1. Prepare four test tubes and place a piece of raw potato in the first test tube, a piece of boiled potato in the second, a piece of raw meat in the third, and a piece of boiled meat in the fourth. Drop a little hydrogen peroxide into each test tube. Observe what happens in each test tube.

2. Make a table showing the activity of each tissue.

"Research Results"

Answer the questions (orally):

In which test tubes did the enzyme activity manifest itself? Explain why?
- How does enzyme activity manifest itself in living and dead tissues? Explain the observed phenomenon.
- Does enzyme activity differ in living tissues of plants and animals?
- Do you think all living organisms contain the enzyme catalase, which ensures the decomposition of hydrogen peroxide?
- Justify your answer.
- Draw a conclusion.
Groups of students report on the completion of the task.

7. Reflection. Students complete the task and draw a conclusion (Slide No. 24).

8. Homework(Slide No. 25):

1. Assignment for everyone: chapter 3.2.1., table “Functions of proteins”,
2. Assignment for those interested in the subject: find a classification of enzymes on the Internet.

LESSON Topic:

"Squirrels"

What is life ?

Philosophical and theoretical idea of ​​​​F. Engels about the essence of life: “Everywhere where we meet life, we find that it is associated with some kind of protein body, and everywhere where we meet any protein body that is not in the process of decomposition, without exception, we also encounter the phenomena of life.”

Definition of life

“Life is a way of existence of protein bodies, the essential point of which is the constant exchange of substances with the external nature surrounding them, and with the cessation of this metabolism, life itself ceases, which leads to the decomposition of the protein.” (F. Engels)

Lesson problem

Today we must reveal the secret of the substances underlying the concept of “life”, i.e. must answer the question “What is protein?”

I invite you to the world of wildlife,

Where interest is our main guide.

We will learn that everything here is not accidental,

Let's find answers, solve mysteries...

Sometimes, so that all doubts are resolved,

Observation will be enough for us.

The question has arisen, or we doubt again -

Then we turn to the experiment.

Lesson topic:

"Squirrels"

Educational:

• expand knowledge about proteins - biological polymers.
• find out the structure, composition and properties of proteins.
• Classify proteins according to their functions in the body.
• with the help of interdisciplinary connections, contribute to the formation of a scientific picture of the world.

Educational:

• formation of basic educational competencies: educational, communicative, personal;
• development of skills and abilities of independent educational work with information sources;
• development of skills to analyze, compare, generalize, draw conclusions, speak in front of an audience;
• formation of a high level of mental activity.

Educational:

• formation of adequate independence STUDENTS ;
• nurturing the need for knowledge, increasing cognitive interests;
• instilling interest in natural sciences.

Issues addressed at LESSON :

• Concept of proteins. Composition and structure of protein molecules.
• The importance of proteins in nature, in the food industry and in human life.

Question No. 1

Concept of proteins. Composition and structure of protein molecules

Proteins are the basis of life

Chemical composition of the human body:

• water 65%,
• fats 10%,
• carbohydrates 5%,
• proteins 18%,
• other inorganic and organic substances 2%.

The predominant component in tissue cells is protein

• Proteins account for more than 50% dry cell mass.
• The protein content in the dry mass of different tissues varies greatly:

- in muscles - 80%,

In the skin - 63%,

In the liver - 57%,

In the brain - 45%,

- in bones -20%.

Proteins have a large molecular weight:

Molecular mass:

• egg albumin is 36,000,
• hemoglobin - 152,000,
• myosin (one of the muscle proteins) - 500,000.

This is thousands and tens of thousands of times greater than the molecular weights of inorganic compounds.

“Life is a way of existence of protein bodies...”

F. Engels

Where there are proteins, there is life, so the second name for proteins is proteins (from the Greek “first”, “most important”).

“To comprehend the infinite, one must first separate,

and then connect"

Goethe

Elementary composition of proteins :

• carbon - 50-55%,
• oxygen - 21-23%,
• nitrogen - 15-17%,
• hydrogen - 6-7%,
• sulfur - 0.3-2.5%.
• Phosphorus, iodine, iron, magnesium and some other elements were also found in individual proteins. Proteins are classified as nitrogen-containing organic compounds.

A huge role in the study of proteins belongs to:

J. Beccari

Frederick Sanger

Fisher

A.Ya.Danilevsky

In 1888, he expressed the idea that proteins consist of amino acid residues connected by peptide bonds.

The first purified protein was obtained in 1728.

L. Pauling

developed ideas about the structure of the polypeptide chain in proteins, first expressed the idea of ​​its helical structure and gave a description of the alpha helix (1951, together with the American biochemist R.B. Corey).

In 1902 he put forward the polypeptide theory of protein structure.

In 1945 he established the structure of insulin, and

in 1953 synthesized it

• Over 170 different amino acids have been found in cells and tissues. All proteins contain only

20 α -amino acids.

• from them can be formed 2 432 902 008 176 640 000 combinations of different proteins that will have exactly the same composition, but different structure and...

Amino acid structure:

All amino acids that make up protein molecules have an amino group in α -position, i.e. at the second carbon atom.

• Write the formula of a tripeptide formed by the amino acids: valine, cysteine, tyrosine .

nonessential amino acids. essential amino acids.

Most of the amino acids that make up proteins can be synthesized in the body during metabolism (from other amino acids supplied in excess). They got the name nonessential amino acids. Some amino acids cannot be synthesized in the body and must be obtained from food. They got the name essential amino acids. There are 8 of them; they are not able to be synthesized in the human body, but enter it with plant foods. What are these amino acids? These are valine, leucine, isoleucine, threonine, methionine, lysine, phenylalanine, tryptophan. Sometimes these include histidine and arginine. The last two are not synthesized in the child’s body.

Most of the amino acids that make up proteins can be synthesized in the body during metabolism (from other amino acids supplied in excess). They got the name nonessential amino acids .

Some amino acids cannot be synthesized in the body and must be supplied to our body through plant foods. They got the name essential amino acids . There are 8 of them. This is valine, leucine, isoleucine, threonine, methionine, lysine, phenylalanine, tryptophan . Sometimes they include histidine and arginine . The last two are not synthesized in the child’s body

The performance of certain specific functions by proteins depends on the spatial configuration of their molecules.

There are 4 levels of protein structural organization

Primary structure

Primary structure A protein is a sequence of amino acid residues linked by peptide bonds.

Protein secondary structure called an orderedly folded polypeptide chain. The main variant of the secondary structure is α - a spiral that looks like an extended spring. It is formed due to intramolecular hydrogen bonds

Tertiary structure

An important role in the formation of the tertiary structure

belongs to radicals, due to which disulfide bridges, ester bonds, and hydrogen bonds are formed.

Quaternary structure

Quaternary structure is the combination of several three-dimensional structures into one whole.

Classic example: hemoglobin, chlorophyll.

In hemoglobin, heme is the non-protein part, globin is the protein part.

Characteristics of three structures of protein molecules

Structure of a protein molecule

Primary - linear

Characteristics of the structure

The order of alternation of amino acids in a polypeptide chain - linear structure

Secondary - spiral

The type of connection that defines the structure

Peptide bond

- NH- CO-

Twisting of a linear polypeptide chain into a helix - helical structure

Graphic image

Tertiary - globular

Packing of the secondary helix into a ball - glomerular (globular) structure or fibrils

Intramolecular hydrogen bonds

Disulfide and ionic bonds

Exercise

Mark in the table the characteristics corresponding to the structures of protein molecules.

From the letters corresponding to the correct ones answers, you will write the name of a qualitative reaction to proteins :

reaction

• reaction

Characteristics of the structures of protein molecules

CHARACTERISTIC

primary

secondary

Globular structure

tertiary

Changes upon denaturation

Linear structure

Spiral structure

Correct answer

CHARACTERISTIC

primary

Structure formed due to intramolecular hydrogen bonds

secondary

Destroyed during protein hydrolysis

tertiary

Globular structure

Changes upon denaturation

Linear structure

The order of alternation of amino acids in a polypeptide chain

Spiral structure

Does not change upon denaturation

The structure is determined by ionic and disulfide bonds

reaction

• reaction

Squirrels – amphoteric electrolytes. At a certain pH value of the medium (it is called the isoelectric point), the number of positive and negative charges in the protein molecule is the same. This is one of the properties of protein. Proteins at this point are electrically neutral, and their solubility in water is the lowest. The ability of proteins to reduce solubility when their molecules reach electrical neutrality is used to isolate them from solutions, for example, in the technology of obtaining protein products.

The process of hydration means the binding of water by proteins, and they exhibit hydrophilic properties:

• They swell, their mass and volume increase.

The swelling of the protein is accompanied by its partial dissolution.

• With limited swelling, concentrated protein solutions form complex systems called jellies.
• Globular proteins can become completely hydrated by dissolving in water (eg milk proteins).
• Fibrillar proteins do not dissolve in water.

Protein Denaturation

• Protein Denaturation- disruption of the natural secondary and tertiary and quaternary structures of the protein under the influence of various factors (temperature, radiation, chemicals, etc.)

Types of denaturation :

• reversible

(i.e. salting out)

• irreversible

Denatured protein loses its biological properties.

The process of restoring the secondary and tertiary structures of a protein is called renaturation.

The foaming process refers to the ability of proteins to form highly concentrated liquid-gas systems called foams.

Proteins are used as foaming agents in the confectionery industry (marshmallows, marshmallows, soufflés).

Bread has a foam structure, and this affects its taste.

For the food industry, two very important properties of proteins can be distinguished:

1) Hydrolysis of proteins under the action of enzymes;

2) Melanoid formation reaction.

The hydrolysis reaction with the formation of amino acids in general can be written as follows:

Conversion of proteins in the body

In animal and human organisms, under the influence of enzymes (pepsin, trypsin, erypsin, etc.), protein hydrolysis occurs. As a result, amino acids are formed, which are absorbed by the intestinal villi into the blood. During these processes, energy is released in the body.

Melanoid formation

Melanoidin formation is understood as the interaction of reducing sugars (monoses and reducing disaccharides, both contained in the product and those formed during the hydrolysis of more complex carbohydrates) with amino acids, peptides and proteins, leading to the formation of dark-colored products - melanoidins

Baked milk

Ryazhenka, Varenets, kefir, baked milk yogurt

• biuret , in which weakly alkaline solutions of proteins interact with a solution of copper sulfate ( II ) with the formation of complex compounds between ions Cu 2+ and polypeptides. The reaction is accompanied by the appearance of a violet-blue color.

Proves the presence of peptide bonds in proteins

• xanthoprotein , in which the interaction of aromatic and heteroatomic cycles in a protein molecule with concentrated nitric acid occurs, accompanied by the appearance of a yellow color;

• Cysteine ​​reaction (sulfhydryl):

The presence of sulfur in proteins is proven by the action of a solution of alkali and lead acetate. The formation of a black precipitate indicates the presence of a sulfide anion in the resulting solution:

Amphotericity

N.H. 3

N.H. 2

Group assignment:

Group number

Object of study

Group No. 1

Protein food

Group No. 2

Silk and wool proteins

1.Prove the presence of proteins in milk and dairy products.

2. Determine the mass fraction of proteins in milk.

3. Analyze the protein content in dairy products.

Group No. 3

1. Investigate the composition and properties of silk and wool proteins.

2. Study the data in the table and answer the question: “What changes occur in wool and silk during the use of products made from them?”

Skin proteins

1. Examine skin proteins.

2. Study the data in the table and answer the question: “What changes occur in leather when using products made from it?”

Storage (backup)

Accumulation of proteins in the body as reserve nutrients

Energy

The ability of protein molecules to oxidize, releasing the energy necessary for the body’s functioning. When 1 g of protein is broken down, 17.6 kJ of energy is released

Transport

For example, hemoglobin is a protein that is part of red blood cells and ensures the transport of oxygen and carbon dioxide

Protective

Antibodies, fibrinogen, thrombin - proteins involved in the development of immunity and blood clotting

Motor (contractile)

Actin and myosin are proteins that make up muscle fibers and ensure their contraction.

Construction

Proteins are elements of all tissues and organs, the plasma membrane of the cell, as well as bones, cartilage, feathers, nails, hair

Hormonal

Hormones are substances that, along with the nervous system, provide humoral regulation of functions in the body

Catalytic or enzymatic

Proteins - catalysts, increasing the rate of chemical reactions in body cells

Receptor

Reaction to external stimulus

Functions of proteins in the cell

Function name

Explanations

Catalytic

Most enzymes are proteins

Construction

The basis of cellular organelles, hair, blood vessels

Motor

Protozoan flagella are contractile proteins; muscle proteins - actin and myosin

Transport

Hemoglobin - transport of oxygen and carbon dioxide

Protective

Antibodies (providing immunity to diseases)

Energy

Some proteins serve as a source of energy

Exercise

Using knowledge from chemistry, biology and everyday life, match the types of proteins and their functions in the human body.

On the tables are sheets with types of proteins printed on them. In the middle column, determine their functions, and in the right column, select an example of one or another type of protein.

BIOLOGICAL FUNCTION

Structural proteins of muscles

EXAMPLE OF PROTEINS

Motor

Connective tissue proteins

Myosin, actin

Construction

Chromosomal proteins

Keratin (skin, hair, nails); collagen (tendon)

Construction

Control proteins

Carriers of oxygen and other substances

Control over the flow of substances in and out of the body, transmission of information within the body (receptor)

Histones (part of chromosome structure)

Membrane receptor proteins

Transport

Enzymes

Hemoglobin

Catalytic

Hormones

Proteases

Regulation of vital processes (regulatory)

Protective proteins

Insulin, sex hormones

Protective

Gammaglobulin, antibodies

Evaluation criteria:

8 - 10 correct answers - “3”

11 - 13 correct answers - “4”

14 - 16 correct answers - “5”

By composition(according to degree of complexity) proteins are distinguished:

• simple proteins - proteins consisting only of amino acids
• complex proteins - proteins - containing a non-protein part, which may include carbohydrates (glycoproteins), lipids (lipoproteins), nucleic acids (nucleoproteins), phosphoric acid (phosphoproteins) (casein)
• complete – contain the entire set of amino acids
• defective - some amino acids are missing in their composition

According to the shape of the molecules:

• globular
• fibrillary

According to solubility in individual solvents:

• water-soluble, soluble in weak saline solutions (albumin)
• alcohol-soluble (prolamins)
• alkali-soluble (glutelins)

Question No. 4

The importance of proteins in nature, in the food industry and in human life

Proteins make up approximately 20 % human body weight and 50 % dry cell mass. In human tissues, proteins are not stored “in reserve”, so their daily intake with food is necessary.

The product's name

Meat

18–22%

The product's name

Fish

Peas

20–36%

17–20%

Eggs

Potato

Milk

1,5–2%

Rye bread

Apples

Millet

0,3–0,4%

Cabbage

Carrot

Beet

0,8–1%

Pasta

Buckwheat

Solving problems with practical content

Task. The most protein is in cheese (up to 25%), meat products (pork 8 - 15, lamb - 16-17, beef 16 - 20%), poultry (21%), fish (13 - 21%), eggs ( 13%), cottage cheese (14%). Milk contains 3% proteins, and bread - 7-8%. Calculate the mass of each of these products, providing the daily protein requirement of an adult equal to 200 g.

Proteins are an essential component of all living cells; they play an important role in living nature and are the main and indispensable component of nutrition. This is due to the enormous role they play in the processes of human development and life. Proteins are the basis of structural elements and tissues, support metabolism and energy, participate in the processes of growth and reproduction, provide mechanisms of movement, the development of immune reactions, and are necessary for the functioning of all organs and systems of the body.

It can be said without exaggeration that protein plays the most important role in the body. Our entire body is built from proteins. Each protein determines some property of the body: the color of the eyes, hair, the structure of internal organs, etc. There are proteins that also perceive heat, smell, taste, and mechanical vibrations. Stimuli “tug” the tip of the protein “ball”, beginning to unwind it. As a result, excitation is transmitted to nerve cells. The hemoglobin protein works on the same principle, carrying oxygen throughout our body.

Protein substances constitute a huge class of organic carbon-nitrogen compounds inevitably found in every organism. The role of proteins in the body is enormous.

Consolidating new material:

Answer the test questions

Answers to the test

Option 1:

• 1 - b,
• 2 - b,
• 3 - a,
• 4 - g,
• 5 B,
• 6 – 1 -a,c; 2 -b,d,
• 7-b,
• 8-a,
• 9-b,
• 10 -v

Option 2 :

• 1 - b,
• 2 - g,
• 3 - a,
• 4 - a,
• 5 - in,
• 6 – 1b, 2 -b, 3 -a, 4 -a;
• 7 - g,
• 8 - b,
• 9 - in,
• 10 - g

Evaluation criteria:

6 – 7 correct answers - “3”

8 - 10 correct answers - “4”

11 - 13 correct answers - “5”

« I have always said and never tire of repeating that the world could not exist if it were so simply structured.”

Homework:

• Study the pages of the textbook:

A.P. Nechaev “Organic chemistry” pp. 291-296

2 . Prepare for laboratory work.

F. Engels

Topic: “Functions of proteins”

• The purpose of the lesson:

• 1. Find out whether proteins are really the “basis of life”
• 2. Prove that proteins are the “basis of life” based on studying the properties and functions of proteins

• 1. Structure of proteins
• 2.Classification and properties of proteins

Biological warm-up 1.Structure of a protein molecule

• 1. High molecular weight organic compound consisting of repeating units
• 2. Violation of the natural structure of the protein
• 3. Repeating units are simple molecules
• 4. Biopolymers; monomers - amino acids
• 5. Strong covalent polar; between amino acids in a protein
• 6. Reversible denaturation
• 7. Violation of the primary structure of the protein

• 1.Why do doctors recommend taking antipyretic medications if the patient’s temperature exceeds 38 o C?
• 2. Why does a boiled egg never produce a chicken?
• 3. Why do chemical workers who are poisoned by salts of heavy metals (Cu, Pb, Pg) give milk to the victims? Give a hygienic justification for studying protein functions?

• 1.What are enzymes?
• 2.What are their functions?
• 3.What is the essence of a catalytic reaction?
• 4.What is the difference between an enzyme and a catalyst?
• 5. How do factors affect the functioning of the enzyme?
• 6. What did you learn about the enzyme catalase?

The substance on which the enzyme acts is called substrate. Substances resulting from an enzymatic reaction are called products reactions

Search task

1. Basic summary

2. Textbook for grade 10 (profile) - pp. 98-99

3. Reference manual – pp. 107 - 110

• Construction
• Receptor
• Regulatory
• Transport
• Protective
• Toxins
• Motor
• Energy
• Storage
• Catalytic

• 1. Structural- proteins participate in the formation of cellular and extracellular structures, for example, they are part of cell membranes, hair (keratin), tendons (collagen), etc.

2. Signal (receptor) - built into cell membranes are protein molecules that can change their tertiary structure in response to environmental factors and thus transmit signals into the cell

3. Regulatory Some hormones are protein in nature. For example, insulin, which regulates blood glucose levels

4. Transport Cell membranes contain special transport proteins that can bind certain substances (glucose, amino acids) and transport them inside cells. Hemoglobin transports oxygen and partially carbon dioxide

5. Protective Immunoglobulins (antibodies) have the ability to recognize foreign proteins or microorganisms that have entered the body and neutralize them. Fibrinogen and prothrombin are involved in the process of blood clotting and protect the body from blood loss.

6. Toxins also classified as proteins that perform a protective function

7. Motor Contractile proteins - actin and myosin- provide muscle contractions in multicellular animals

8. Energy When 1 g of protein breaks down into final products, it is released 17.6 kJ energy

9. Storage Egg albumin and milk casein are animal reserve proteins

1. Select a function that is performed almost exclusively by proteins in the body.

energy

regulatory

informational

enzymatic

2. Function that proteins cannot perform:

transport

catalytic

matrix

energy

3. Enzymes are called

protein catalysts

regulatory proteins

substrates

denatured alcohols

4. Choose a protein that primarily performs a motor function

collagen

myoglobin

5. Select the protein that performs the enzyme

tive function

6. Choose a protein that performs a protective function

albumen

glucagon

antibody

Task: Establish a correspondence between proteins and their functions

Proteins: Functions

A. Keratin

B. Hemoglobin B. Actin G. Antibodies D. Myosin E. Fibrinogen

Z. Albumin

I. Catalase

K. Pepsin

L. Insulin

1. Construction 2. Storage

3. Protective

4. Motor

5. Transport

6. Enzymatic

7. Regulatory

D.Z: s. 95 – 99(1) With. 44- 47(2)