Properties and features of proteins presentation. Presentation of "Protein Functions" on Biology - Project, Report

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Presentation on the topic: Presentation of the function of proteins

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Proteins proteins (proteins, polypeptides) - High solucelastic organic substances consisting of alpha-amino acids connected to a peptide tension chain. Proteins are an important part of the nutrition of animals and humans, since all necessary amino acids can not be synthesized in their body and some of them comes with protein food. In the process of digestion, the enzymes destroy the consumed proteins to amino acids, which are used in the biosynthesis of organism proteins or are subjected to further decay for energy.

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

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Structural function. The structural function of proteins is that proteins are involved in the formation of almost all cell organoids, in many respects determining their structure (form); form a cytoskeleton, giving the shape of cells and many organides and providing the mechanical form of a row of tissues; Part of the intercellular substance is largely determining the structure of tissues and the shape of the body of animals. The structural proteins include: -Kollagen -Akortin-Elastin -Myozin -Ceratin -Tubulin

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Catalytic function. (enzymatic) The most well-known role of proteins in the body is the catalysis of various chemical reactions. Enzymes - a group of proteins, which has specific catalytic properties, that is, each enzyme catalyzes one or more similar reactions, accelerating them. Example: 2N202 → 2N20 + 02 In the presence of iron salts (catalyst), this reaction is somewhat faster. Catalase enzyme for 1 sec. Splits up to 100 thousand molecules H202. Molecules that join the enzyme and change as a result of the reaction are called substrates. The mass of the enzyme is much larger than the mass of the substrate. A part of the enzyme that joins the substrates contains catalytic amino acids, is called an active enzyme center.

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Motor function. Muscular reduction is a process, during which the transformation of chemical energy, stored in the form of macroeergic pyrophosphate bonds in ATP molecules, into mechanical work. Direct participants in the reduction process are two proteins - Aktin and Miosin. Special contractile proteins (Aktin and Miosin) are involved in all types of cells of the cell and the body: the formation of pseudopodies, the flickering of the cilia and the beating of flavors in the simplest, cutting muscles in multicellular animals, the movement of the leaves in plants, etc.

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Energy function. Energy function - proteins serve as one of the sources of energy in the cell. When decaying 1 g of protein to final products, 17.6 kJ of energy is highlighted. First, the proteins fall to the amino acids, and then to the final products: - water, -th particle gas, ammoniac. But as a source of energy, proteins are used extremely rarely.

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Immune function. (antibiotics) at the time when pathogens fall into the body - viruses or bacteria, special proteins begin to be produced in specialized organs - antibodies that bind and neutralize pathogens. The peculiarity of the immune system is that at the expense of antibodies, it can fight with almost any kind of pathogens. Interferons also includes protective proteins of the immune system. These proteins produce cells infected with viruses. Their effects on neighboring cells provide antiviral stability, blocking viruses reproduction in target cells or assembling virus particles. Interferons possess other mechanisms of action, for example, affect the activity of lymphocytes and other cells of the immune system.

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Toxins toxins, toxic substances of natural origin. Typically, toxins include high-molecular compounds (proteins, polypeptides, etc.), when antibodies are produced into the body. The target of the actions of the toxins are separated by -Gematic poisons - poisons affecting blood. -Notoxins - poisons affecting the nervous system and brain. -Mooxed poisons - poisons, damaging muscles. -Hemotoxins - toxins that damage blood vessels and cause bleeding. -Gemolytic toxins are toxins that damage red blood cells. -Nofrotoxins are toxins that damage the kidneys. -Cardiotoxins are toxins that damage the heart. -Necrotoxins are toxins that destroy the tissue, causing their oversonation (necrosis). Consider the poisons of plants: Falllotoxins and amatexins are contained in various types: pale toadstool, unmanion stinking, Spring. White leafing (Fig. 1) is a deadly poisonous mushroom, contains the poisons of Amanitina and Virozin. For a person, the deadly dose of A-amanitine 5-7 mg, phallotidine 20-30 mg (in one mushroom, an average of up to 10 mg of phalloididine, 8 mg of L-amanitin and 5 mg b-amanitis). When poisoning, there is a fatal outcome.

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Hormonal function. Hormonal function. The metabolism in the body is governed with a variety of mechanisms. In this Regulation, hormones are occupied, synthesized not only in the glands of internal secretion, but also in many other organism cells (see below). A number of hormones are represented by proteins or polypeptides, such as pituitary hormones, pancreas, etc. Some hormones are derived amino acids.

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Nutritional function. (backup) nutrient (backup) function. This function is performed by so-called backup proteins that are power sources for the fetus, such as egg proteins (ovalbumin). The main milk protein (casein) also performs mainly nutrient 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 governing metabolic processes. Casein Milk Albumin Eggs

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Proteins Enzymes Protective Antibiotics Structural Motor Protective Toxins Spare Receptor Hormones Catalytic Transport Contracting

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Structural function. The structural function of proteins is that proteins are involved in the formation of almost all cell organoids, in many respects determining their structure (form); form a cytoskeleton, giving the shape of cells and many organides and providing the mechanical form of a row of tissues; Part of the intercellular substance is largely determining the structure of tissues and the shape of the body of animals. Structural proteins include: -collagen -Aktin-Elastin -Myozin -Ceratin -Tubulin protein keratin

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Transport function. The transport function of proteins is the participation of proteins in the transfer of substances into cells and from the cells, in their displacements inside the cells, as well as in their transport with blood and other body fluids. There are different types of transport that are carried out using proteins. Movements of substances through the cell membrane Transfer of substances inside the cell Transfer of substances by the body For example, the oxygen transfers oxygen

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Protective function. Protect the body from the invasion of alien organisms and from damage to the antibody blocks alien proteins, for example, fibrinogen and protontine provide blood coagulation

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Protective function. In response to penetration into the organism of alien proteins or microorganisms (antigens), special proteins are formed - antibodies that can bind and neutralize them.

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Receptor function. Proteins receptors are protein molecules built into the membrane capable of changing their structure in response to the attachment of a certain chemical substance.

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Contact function. Proteins - participate in the reduction of muscle fibers. Contact function. Many protein substances are involved in the act of muscle contraction and relaxation. However, actin and myosin are played by the main role in these vital processes - specific muscle tissue proteins. The contractile function is inherent not only to muscle proteins, but also proteins of the cytoskeleton, which ensures the subtlest processes of the vital cells of the cells (the discrepancy of chromosomes during mitosis). Aktin and Miosin - muscle proteins

What proteins are called sour? Proteins, in which more acid amino acids, lowering pH. What proteins are called neutral? Proteins in which the same amount of carboxyl and amino groups. Why are proteins are powerful buffer systems? Can attach or give hydrogen ions, supporting a certain pH level. What is protein denaturation? The process of loss of three-dimensional conformation inherent in this protein molecule is called denaturation. What is renaultation? The process of restoring the structure of the protein after denaturation is called renaturation. Give examples of soluble and insoluble proteins: soluble (blood plasma proteins - fibrinogen, protontine, albumin, globulins), insoluble proteins that perform mechanical functions (Fibroin, keratin, collagen). Give examples of proteins resistant to external influences: Fibroin - web protein, keratin - hair proteins, collagen - protein tendons.

Theme lesson:

"Proteins"

What is life ?

Philosophical and theoretical representation of F. Engels about the essence of life: "Everywhere, where we meet life, we find that it is connected with any protein body, and everywhere, where we meet any protein body that is not in the decomposition process, We do not meet the phenomena of life without exception. "

Defining Life

"Life is a way of the existence of protein bodies, a significant moment of which is the constant metabolism with their surrounding foreign nature, and life itself, which leads to the decomposition of the protein, is stopped with the cessation of this metabolism. (F. Engels)

The problem of lesson

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

I invite you in the wildlife world,

Where is the interest - our main landmark.

We find out that everything is not accidental here,

We will find the answers, solve secrets ...

Sometimes all doubts were resolved,

It will be enough for us to observe.

The question arose, Ile again doubt -

Then we appeal to the experiment.

Subject lesson:

"Proteins"

Educational:

expand the knowledge of proteins - biological polymers.
find out the structure, composition and properties of proteins.
classify proteins by their functions in the body.
with the help of interprete relationships contribute to the formation of the scientific picture of the world.

Developing:

formation of basic training competencies: educational, communicative, personal;
development of skills and skills of independent learning hours with information sources;
development of skills to analyze, compare, summarize, draw conclusions, appear before the audience;
formation of high level of mental activity.

Educational:

formation of adequate independence Students ;
upbringing need for knowledge, increasing cognitive interests;
increasing interest in natural sciences.

Questions considered on LESSON :

Concept of proteins. The composition and structure of protein molecules.
The value of proteins in nature, in the food industry and in a person's life.

Question number 1.

Concept of proteins. Composition and structure of protein molecules

Proteins - the basis of life

Chemical composition of the human body:

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

The prevailing component in tissue cells is protein

The proportion of proteins has more 50% Dry mass cell.
The protein content in the dry mass of different tissues is very different:

- 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,
mieozina (one of the muscle proteins) - 500,000.

It is thousands and tens of thousands of times more molecular masses of inorganic compounds.

"Life is a way of existence of protein bodies ...".

F. Engels.

Where there are proteins, there is a life, so the second name of proteins - proteins (from the Greek "First", "the most important").

"To comprehend the infinite, you must first disconnect,

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%.
Composition of individual proteins also found phosphorus, iodine, iron, magnesium and some other elements. Proteins refer to nitrogen-containing organic compounds.

A huge role in the study of proteins belongs:

Ya. Beckari

Frederick Senjer

Fisher

A.Ya. Danilevsky

In 1888, he expressed the idea that proteins consist of residual amino acids connected by peptide bond.

The first purified protein was obtained in 1728.

L. POLING

he developed ideas about the structure of the polypeptide chain in proteins, first expressed the thought of her spiral structure and gave a description of the alpha spiral (1951, together with the American biochemist R. B. Corey).

In 1902, he put forward the polypeptide theory of the structure of proteins.

In 1945, established the structure of insulin, and

in 1953 synthesized it

Over 170 different amino acids were found in cells and tissues. As part of all proteins enters only

20 α - amino acids.

of them can be formed 2 432 902 008 176 640 000 combinations of various proteins that will possess exactly the same composition, but different buildings and ...

The structure of amino acids:

in all amino acids that are part of protein molecules, the amino group is in α -Put, i.e. In the second carbon atom.

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

replaceable amino acids. indispensable amino acids.

Most amino acids that are part of proteins can be synthesized in the body during the exchange process (from other amino acids in excess). They got a name replaceable amino acids. Some amino acids cannot be synthesized in the body and should enter our body with food. They got a name indispensable amino acids. They are 8, they are not capable of synthesized in the human body, but they come into it with vegetable food. What are these amino acids? This is valine, leucine, isoleucine, threonine, methionine, lysine, phenylalanine, tryptophan. Sometimes their number includes histidine and arginine. The last two are not synthesized in the body's body.

Most amino acids that are part of proteins can be synthesized in the body during the exchange process (from other amino acids in excess). They got a name replaceable amino acids .

Some amino acids cannot be synthesized in the body and should enter our organism with vegetable food. They got a name indispensable amino acids . They are 8. That's valin, Leucine, Isolecin, Treonin, Methionine, Lizin, Phenylalanine, Triptofan . Sometimes they include gistidin and Arginine . The two latter are not synthesized in the body of the child

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

4 levels of structural organization of protein

Primary structure

Primary structure protein is called the sequence of amino acid residues associated with peptide bonds

Secondary structure of protein called an orderly rolled polypeptide chain. The main variant of the secondary structure is α - Spiral, having a view of a stretched spring. It is formed due to intramolecular hydrogen ties

Tertiary structure

In the formation of the tertiary structure a big role

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

Quaternary structure

Quaternary structure - This is the union of several three-dimensional structures in one whole.

Classic example: hemoglobin, chlorophyll.

In hemoglobin, Gem is a non-worn part, Globin - the protein part.

Characteristic of the three structures of protein molecules

Structure of a protein molecule

Primary - linear

Characteristic structure

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

Secondary - spiraloid

Communication type defining structure

Peptide communication

- NH- CO-

Tightening of the polypeptide linear chain in the spiral - spiral structure

Graphic picture

Tertiary - globular

Packaging of secondary spirals in the ball - the glomerular (globular) structure or fibrils

Intramolecular hydrogen bonds

Disulfide and ionic connections

The task

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

From letters corresponding to the right answers, you will be the name of a high-quality reaction to proteins :

reaction

reaction

Characteristics of the structures of protein molecules

CHARACTERISTIC

primary

secondary

Globular structure

tertiary

Varies with denaturation

Linear structure

Spiral structure

Correct answer

CHARACTERISTIC

primary

Structure formed by intramolecular hydrogen bonds

secondary

Collapsed in protein hydrolysis

tertiary

Globular structure

Varies with denaturation

Linear structure

The order of alternation of amino acids in the polypeptide chain

Spiral structure

Does not change at denaturation

The structure is determined by ionic and disulfide bonds

reaction

reaction

Proteins - amphoteric electrolytes. With a certain value of the pH of the medium (it is called an isoelectric point) the number of positive and negative charges in the protein molecule is equally. This is one of the properties of the protein. Proteins at this point are either either, and their solubility in water is the smallest. The ability of proteins to reduce the solubility when the electrophetrality is reached, their molecules is used to release them from solutions, for example, in the technology of obtaining protein products.

The hydration process means binding to water proteins, and they exhibit hydrophilic properties:

Swelling, 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 jellyts.
Globular proteins can be completely hydrated, dissolving in water (for example, milk proteins).
Fibrillar proteins do not dissolve in water.

Denaturation protein

Denaturation protein - violation of natural secondary and tertiary and quaternary protein structures under the action of various factors (temperature, radiation, chemical substances, etc.)

Types of denaturation :

reversible

(i.e.shiting)

irreversible

The denatured protein loses its biological properties.

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

Under the process of foaming, the ability of proteins to form high-concentrated liquid systems "MAZ", called foams.

Proteins are used as foaming in the confectionery industry (grazing, marshmallow, souffle).

The structure of the foam has bread, and this affects its taste properties.

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

1) hydrolysis of proteins under the action of enzymes;

2) reaction of melanoidin formation.

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

Transformation of proteins in the body

In animal and human organisms under the influence of enzymes (pepsin, trypsin, eiphin, etc.), proteins are hydrolysis. As a result, amino acids are formed, which are absorbed by the guts in the blood in the blood. With these processes, energy is allocated in the body.

Melanoidino formation

Under the melanoidin formation, the interaction of restoring sugars (monoses and restoring disaccharides, both contained in the product, and formed pi hydrolysis of more complex carbohydrates) with amino acids, peptides and proteins, leading to the formation of dark-painted products - melanoidin

Baked milk

Ryazhenka, Varense, kefir, yogurt made of grained milk

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

Proves the presence of peptide bonds in proteins

xantoprotein at which aromatic and heteroatomic cycles interact in the protein molecule with concentrated nitric acid, accompanied by the appearance of yellow color;

Cysteine \u200b\u200breaction (Sulfgidrile):

The presence of sulfur proteins proves the effect of alkali and lead acetate. The loss of black sediment indicates the presence of a solution of sulfide anion in the resulting solution:

Amphoterity

NH 3

NH 2

Setting Groups:

Group number

Object of study

Group №1

Food proteins

Group №2.

Silk and wool proteins

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

2. Condiminate the mass fraction of proteins in milk.

3. Make the analysis of protein content in dairy products.

Group number 3.

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

2. Explore the table data and answer the question: "What changes occur in wool and silk during the operation of products from them?"

Skin proteins

1. Explore skin proteins.

2. Explore table data and answer the question: "What changes occur in the skin during the operation of products from it?"

Purchase (backup)

The accumulation of proteins in the body as spare nutrients

Energy

The ability of protein molecules to oxidation with the release of energy necessary for the livelihoods. When splitting 1 g of protein, 17.6 kJ of energy is distinguished

Transport

For example, hemoglobin - protein, which is part of the erythrocyte and providing the transfer of oxygen and carbon dioxide

Protective

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

Muscular (contractile)

Aktin and Miosin are proteins that are part of muscle fibers and ensuring their reduction.

Construction

Proteins - elements of all tissues and organs, plasma membrane cells, as well as bones, cartilage, feathers, nails, hair

Hormonal

Hormones - substances that provide on a row with a nervous system humoral regulation of functions in the body

Catalytic or enzymatic

Proteins - catalysts, increasing chemical reaction rate in organism cells

Receptor

Reaction to the external stimulus

Protein functions in a cage

Function name

Explanations

Catalytic

Most enzymes - proteins

Construction

The basis of cell organoids, hair, vessels

Motor

Flagella flags - contractile proteins; Muscle proteins - Aktin and Miosin

Transport

Hemoglobin - oxygen and carbon dioxide transport

Protective

Antibodies (providing immunity to diseases)

Energy

Some proteins serve as a source of energy.

The task

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

On the tables sheets with printed types of proteins. In the middle column, determine their functions, and in the right-way, select an example of a particular type of proteins.

Biological function

Structural muscle proteins

Example of proteins

Motor

Printed tissue proteins

Mozin, Aktin

Construction

Chromosomal proteins

Keratin (leather, hair, nails); Collagen (tendon)

Construction

Controlling proteins

Oxygen carriers and other substances

Control over the stream of substances inside and outside the body, the transfer of information inside the body (receptor)

Histons (part of the structure of chromosomes)

Membranes receptors proteins

Transport

Enzymes

Hemoglobin

Catalytic

Hormones

Protease

Regulation of life processes (regulatory)

Protective proteins

Insulin, sex hormones

Protective

Gammaglobulin, antibodies

Criteria ratings:

8 - 10 correct answers - "3"

11 - 13 correct answers - "4"

14 - 16 correct answers - "5"

According to the composition (according to the degree of complexity) distinguish proteins:

simple proteins - proteins consisting only of amino acids
sophisticated proteins - proteids - containing a non-peculiar part, which may include carbohydrates (glycoproteins), lipids (lipoproteins), nucleic acids (nucleoproteides), phosphoric acid (phosphoproproids) (casein)
full - contain the whole set of amino acids
defective - there are no amino acids in their composition

Molecules:

globular
fibrille

Solubility in individual solvents:

water soluble soluble in weak saline solutions (albumin)
spiritanishable (Prolamines)
soluble in alkalis (bugness)

Question number 4.

The value of proteins in nature, in the food industry and in a person's life

Proteins make up about 20 % mass of the human body and 50 % Dry mass cell. In man's tissues, proteins are not postponed "about the supply", therefore, their daily arrival with food is necessary.

The product's name

Meat

18–22%

The product's name

A fish

Peas

20–36%

17–20%

Eggs

Potatoes

Milk

1,5–2%

Rye bread

Apples

Millet

0,3–0,4%

Cabbage

Carrot

Beet

0,8–1%

Pasta

Buckwheat grain

Solving tasks with practical content

A task. Most protein in cheese (up to 25%), meat products (in pork 8 - 15, lamb - 16-17, beef 16 - 20%), in a bird (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, ensuring the daily need of an adult in proteins equal to 200g.

Proteins are a mandatory component of all living cells, they play an important role in wildlife, are the main and indispensable component of nutrition. This is connected with the huge role they play in the processes of development and human life. Proteins are the basis of structural elements and tissues, maintain the metabolism and energy, participate in the processes of growth and reproduction, ensure mechanisms of movement, the development of immune reactions, is necessary for the functioning of all organs and organism systems.

It is possible without exaggeration to say that the protein plays in the body the most important role. The proteins are built all our body. Each protein determines some property of the body: the color of the eyes, hair, the structure of the internal organs, etc. There are proteins that are also warm, smell, taste, mechanical oscillations. The stimpers "jerk" for the tip of a protein "tangle", starting to unwind it. As a result, the excitation is transmitted to nervous cells. For the same principle, hemoglobin protein operating in our body oxygen works.

Protein substances constitute a huge class of organic carbon-nitrogenous compounds, inevitably encountered in each organism. The role of proteins in the body is enormous.