1 slide
2 slide
Wherever we meet life, we find it associated with some protein body. F. Engels The purpose of the lesson: To continue expanding and deepening knowledge about the most important organic substances of the cell based on the structure of proteins, to form knowledge about the most important role of proteins in the organic world, the implementation of the concept of the unity of natural science disciplines
3 slide
Lesson objectives: a) educational - to update the knowledge necessary to study the topic; - introduce students to the structure of proteins; - bring them to a conscious study of the function of proteins; b) developing - development of general educational skills and abilities; - development of the ability to analyze information, compare the proposed objects, classify according to various criteria, generalize; work by analogy; - development of cognitive interest and creative abilities; c) educators - education of a conscious attitude to a healthy lifestyle; - education of a moral attitude to life as the highest value; - the formation of skills to adapt to the conditions of a constantly changing life with the help of acquired knowledge, skills and abilities
4 slide
What will be discussed? Gerard Mulder is a Dutch biochemist who first discovered protein in 1838. The word "protein" comes from the Greek word "proteios", which means "in first place".
5 slide
Our task: to find out the chemical structure and biological role of proteins. Indeed, all life on earth contains proteins. They make up about 50% of the dry body weight of all organisms. In viruses, the protein content ranges from 45 to 95%. In the bacterial cell of Escherichia coli there are 5 thousand molecules of organic compounds, of which 3 thousand are proteins. In the human body, more than 5 mil. proteins
6 slide
7 slide
What protein names do you remember? Where they are? albumin myosin pepsin interferon
8 slide
9 slide
How is protein structured? Proteins are complex high-molecular natural compounds built from α-amino acids. H R1 O NH2 - amino group N - C - C R - radical H H OH COOH - carboxyl group
10 slide
11 slide
Proteins contain 20 different amino acids (they are called magic), hence the huge variety of proteins.
12 slide
13 slide
Laboratory work We work on instructive cards. Color reactions for proteins: Xantoprotein; biuret; Cysteine.
14 slide
Name the structures of the protein and the types of chemical bonds corresponding to these structures
15 slide
How is protein structured? The primary is a straight chain of amino acids held together by peptide bonds. It is the primary structure of the protein molecule that determines the properties of the protein molecules and its spatial configuration.
16 slide
How is protein structured? The secondary structure is the ordered folding of the polypeptide chain into a helix. The coils of the helix are strengthened by hydrogen bonds that arise between carboxyl groups and amino groups. Tertiary structure - the laying of polypeptide chains into globules resulting from the occurrence of chemical bonds (hydrogen, ionic, disulfide)
17 slide
How is protein structured? The quaternary structure is characteristic of complex proteins, the molecules of which are formed by two or more globules. Subunits are held in the molecule by ionic, hydrophobic, and electrostatic interactions.
18 slide
Chemical properties of proteins Hydrolysis of proteins is reduced to the cleavage of polypeptide bonds Denaturation - violation of the natural structure of the protein under the influence of heat and chemical reagents
19 slide
During denaturation, both complete destruction of protein structures and partial destruction occur. If the primary structure is not destroyed, then this process is called renaturation Chemical properties of proteins
20 slide
21 slide
Functions of proteins Structural Participate in the formation of cellular and extracellular structures: they are part of cell membranes (lipoproteins, glycoproteins), hair, horns, wool (keratin), tendons, skin (collagen), etc. Motor Contractile proteins actin and myosin provide muscle contraction in multicellular animals: myosin - muscles
22 slide
Functions of proteins Transport The blood protein hemoglobin attaches oxygen and transports it from the lungs to all tissues and organs, and from them carbon dioxide transfers to the lungs; The composition of cell membranes includes special proteins that provide an active and strictly selective transfer of certain substances and ions from the cell to the external environment and back.
23 slide
Functions of proteins Protective 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. Fibrin, formed from fibrinogen, helps to stop bleeding. Signal Molecules of proteins are embedded in the surface membrane of the cell, capable of changing their tertiary structure in response to environmental factors, thus receiving signals from the external environment and transmitting commands to the cell: rhodopsin - visual purple
24 slide
Functions of proteins Regulatory Hormones of protein nature are involved in the regulation of metabolic processes. For example, the hormone insulin regulates blood glucose levels, promotes glycogen synthesis, and increases the formation of fats from carbohydrates. Energy The breakdown of 1 g of protein to end products releases 17.6 kJ. First, proteins break down to amino acids, and then to the final products - water, carbon dioxide and ammonia. Storage In plants, proteins are stored in the form of aleurone grains, they are not stored in animals, with the exception of egg albumin, milk casein. But during the breakdown of hemoglobin, iron is not excreted from the body, but is stored, forming a complex with the ferritin protein.
Functions of proteins
1. Structural function.
Proteins are part of all
cellular
organelle:
membranous - plasmalemma,
nuclear
shell,
endoplasmic
or
reticular
network
(ER),
Golgi complex, lysosomes,
peroxisomes,
vacuole,
mitochondria, plastids and
non-membrane - chromosomes,
ribosomes, cell center
(centrioles),
cilia
and
flagella, microfilaments.
All enzymes are proteins. This function ceased in 1982
be considered unique. It turned out that some RNAs also
have catalytic activity. They are called
RNAzymes.
3. Protective function (for now
is unique).
Antibodies
This
proteins.
Immunoglobulins stick together
antigens
and
formed
precipitate 4. Regulatory function.
At the cellular level: proteins - repressors and transcription activators.
At the organism level: some hormones
proteins.
For example, insulin is a hormone produced by the pancreas.
Regulates the passage of glucose through the plasmalemma. At
insufficient secretion of insulin develops
heavy
disease
sugar
diabetes.
Somatotropin is a growth hormone. Formed in the front
share
pituitary.
There
same
formed
and
adrenocorticotropic hormone (ACTH). He acts
on the adrenal cortex, regulating the synthesis of steroid
hormones. 5. Energy transformation.
The retinal proteins rhodopsin and retinene transform
light energy into electrical energy. Actin-myosin
complexes in the muscles convert the energy of chemical
links to mechanical.
6. Transport function.
Hemoglobin
carries out
transport
O2
CO2.
Transferrin
transport
gland.
Permease systems are membrane proteins that
transport polar compounds across the membrane
and against the concentration gradient. 7. Energy function.
11 of the 20 amino acids that make up proteins
the human body "burn" with the release of energy.
These are non-essential amino acids. They may be
synthesized in the cell from cleavage products
carbohydrates and lipids
8. Buffer function.
Any protein is an amphoteric polyelectrolyte. Squirrels
contribute to the maintenance of certain pH values
in different compartments of the cell, providing this
compartmentalization. 9. Nutritional function.
a) Supply of essential amino acids. A person has 9 of
20 amino acids cannot be synthesized in
body. They must come from outside.
The concept of "essential and irreplaceable amino acids" is species-specific and applies only to animals and
mushrooms.
b) Spare proteins for the development of the embryo and
feeding the baby. For example, casein is a protein
milk, ovalbumin - egg white, gliadin - protein
grains of wheat.
AMINO ACID
The formula is correct for 19 of20
amino acids,
found in proteins. AT
composition of proteins other than these
19 amino acids included
one imino acid proline.
in all amino acids
available
amino group.
Hence the name - "α
amino acids".
In nature, there are two forms of stereoisomers: L (left-handed) and
D (dextrorotatory). In addition to L - amino acids included in proteins, in
the body also has D-amino acids, which are not included in proteins.
The general formula of an amino acid is shown in the figure. PROTEINOGENIC AMINO ACIDS ARE CLASSIFIED:
- according to the structure of the side chain (R-groups)
aliphatic, aromatic and heterocyclic amino acids;
- by additional groups in the radical
diaminomonocarboxylic (two NH2 groups and one COOH group),
monoamine dicarboxylic (one
NH2 group and two COOH groups),
hydroxyamino acids, sulfur-containing, imino acids (NH)
- according to the position of the isoelectric point
neutral, basic and acidic
- according to the polarity of R-groups, i.e. ability of R-groups to interact with water
under appropriate intracellular pH conditions (pH near 7.0)
with non-polar or hydrophobic R-groups, polar but not
charged R-groups, negatively charged R-groups and
positively charged R-groups
- according to the ability to synthesize in the animal body
and replaceable and irreplaceable. 1. Non-polar or hydrophobic radicals.
Aliphatic - alanine, valine, leucine, isoleucine.
Sulfur containing methionine. Aromatic - phenylalanine,
tryptophan. Proline imino acid.
2. Polar but uncharged radicals. Glycine.
hydroxyamino acids
serine,
threonine,
tyrosine.
containing
sulfhydryl
group
cysteine.
Containing an amide group: asparagine, glutamine.
3. Negatively charged radicals. Aspartic
acid, glutamic acid.
4. Positively charged radicals.
Lysine, arginine, histidine.
Peptide bond
Polypeptide
H2N- CH - CO - (NH - CH - CO) n - NH - CH - COOH│
│
│
R
R
R
(N-terminus)
(C-end)
PRIMARY STRUCTURE is linear, represented
sequence
amino acids,
connected by peptide bonds SECONDARY STRUCTURE
The secondary structure is spatial, it
formed only by hydrogen bonds of the pepid backbone
between C=O and N-H groups of different amino acids.
Allocate α-helix, β-folded sheet and collagen
spiral Classification by type of building
fibrillar proteins
Globular proteins
Membrane proteins Types of location of the secondary structure in globules TERTIARY STRUCTURE
The tertiary structure of a protein is a spatial
the conformation of a polypeptide having a secondary structure,
and due to interactions between radicals.
THE TERTIARY STRUCTURE IS COMPLETELY SET BY THE PRIMARY
What proteins are called acidic? Proteins with more acidic amino acids that lower the pH. What proteins are called neutral? Proteins in which the same number of carboxyl and amino groups. Why are proteins powerful buffer systems? Able to attach or give hydrogen ions, maintaining a certain pH level. What is protein denaturation? The process of losing the three-dimensional conformation inherent in a given protein molecule is called denaturation. What is renaturation? The process of restoring the protein structure after denaturation is called renaturation. Give examples of soluble and insoluble proteins: Soluble (blood plasma proteins - fibrinogen, prothrombin, albumin, globulins), insoluble proteins that perform mechanical functions (fibroin, keratin, collagen). Give examples of proteins that are resistant to external influences: Fibroin is a web protein, keratin is a hair protein, collagen is a tendon protein.
1 of 19
Presentation on the topic: Presentation Functions of proteins
slide number 1
Description of the slide:
slide number 2
Description of the slide:
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 all the necessary amino acids cannot be synthesized in their bodies and some of them come with protein foods. During digestion, enzymes break down ingested proteins into amino acids, which are used in the body's protein biosynthesis or further broken down for energy.
slide number 3
Description of the slide:
slide number 4
Description of the slide:
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 course of biochemical reactions and play an important role in metabolism. Eukaryotic cytoskeleton (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, in the immune response and in the cell cycle.
slide number 5
Description of the slide:
structural function. The structural function of proteins is that proteins are involved in the formation of almost all cell organelles, largely determining their structure (shape); form a cytoskeleton that 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 number 6
Description of the slide:
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 with 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 is somewhat faster. Catalase enzyme for 1 sec. splits up to 100 thousand H202 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 the substrates contains catalytic amino acids, called the active site of the enzyme.
slide number 7
Description of the slide:
motor function. Muscle contraction is a process during which the 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 number 8
Description of the slide:
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 inside 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 with the help of proteins.
slide number 9
Description of the slide:
slide number 10
Description of the slide:
slide number 11
Description of the slide:
Energy function. Energy function - proteins serve as one of the sources of energy in the cell. The breakdown of 1 g of protein to final products releases 17.6 kJ of energy. First, proteins break down to amino acids, and then to the final products: -water, -carbon dioxide, -ammonia. But proteins are rarely used as an energy source.
slide number 12
Description of the slide:
slide number 13
Description of the slide:
immune function. (antibiotics) At the moment when pathogens - viruses or bacteria - enter the body, special proteins begin to be produced in specialized organs - antibodies that bind and neutralize pathogens. The peculiarity of the immune system is that, due to antibodies, it can fight almost any kind of pathogens. Interferons are also 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 reproduction 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 number 14
Description of the slide:
Toxins Toxins, toxic substances of natural origin. Usually, high-molecular compounds (proteins, polypeptides, etc.) are classified as toxins, which, when they enter the body, produce antibodies. According to the target of action, toxins are divided into - Hematic poisons - 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 - toxins that destroy tissues, causing their necrosis (necrosis). Consider plant poisons: Fallotoxins and amatoxins are found in various species: pale grebe, smelly fly agaric, spring. White toadstool (Fig. 1) - a deadly poisonous mushroom, contains the poisons of amanitin and virozin. For humans, the lethal dose of a-amanitin is 5-7 mg, phalloidin 20-30 mg (on average, one mushroom contains up to 10 mg of phalloidin, 8 mg of L-amanitin and 5 mg of B-amanitin). When poisoned, death occurs.
Description of the slide:
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, such as hormones of the pituitary gland, pancreas, etc. Some hormones are derivatives of amino acids.
slide number 17
Description of the slide:
nutritional function. (reserve) Nutritional (reserve) function. This function is performed by the so-called reserve proteins, which are sources of nutrition for the fetus, such as egg proteins (ovalbumins). The main protein of milk (casein) also performs a mainly 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
PROTEINS, THEIR STRUCTURE, PROPERTIES. BIOLOGICAL FUNCTIONS OF PROTEINS.
- Lepeshenko T.I.
- GBOU NPO RO PU No. 61
- Novoshakhtinsk, Rostov region
- Educational:
- Introduce students to natural polymers - proteins. To study their structure, classification and properties. To reveal the biological significance in human life. Describe the most important constituents of food.
- Educational:
- Cultivate a positive attitude towards chemistry.
- Developing:
- To develop the ability to work with an ever-increasing information flow, develop logical thinking, independence of judgment, form the ability and skills of oral speech, thinking skills that are necessary not only in studies, but also in everyday life.
- The reaction for obtaining aniline from nitrobenzene is called ………
- The main properties of amino acids are due to the presence in the molecule - NH2. What is it?
- The acidic properties of amino acids are due to the presence in the molecule of ......
- An aniline solution can be determined using …….
- Methylamine can be considered as a derivative of ……
- Zinina
- Amino group
- bromine water
- ammonia, in which hydrogen atoms are replaced by hydrocarbon radicals
- Albumin (in chicken egg)
- Hemoglobin (in human blood)
- Casein (in cow's milk)
- Myoglobin and myosin (in muscles)
- – NH – CH – C – NH – CH – C – NH – CH –
- │ ║ │ ║ │
- R1 O R2 O R3
- Muscles up to 80%
- Lungs-72%
- Skin-63%
- Liver-57%
- Brain-15%
- Adipose and bone tissue, teeth-14-28%
- C - 50 - 52%;
- H - 6.0 - 8.0%;
- O - 19 - 24%;
- N - 15 - 18%;
- S - 0.5 - 2.0%.
- Squirrels
- simple complex
- consist only contain protein
- from amino acids and non-protein part
- (albumin, fibrin) (lipids, carbohydrates,
- metal ions -
- proteolipids,
- hemoglobin)
- By solubility:
- 1.Soluble
- 2.Insoluble
- By state of aggregation:
- 1.Liquid
- 2.Solid
- In 1903, the German scientist E. G. Fischer proposed the peptide theory, which became the key to the mystery of the structure of the protein. Fisher suggested that proteins are polymers of amino acid residues connected by a NH-CO peptide bond.
- The idea that proteins are polymeric formations was expressed as early as 1888 by the Russian scientist A.Ya. Danilevsky.
- Protein is a high molecular weight organic compound, which is a biopolymer consisting of monomers, which are α-amino acids linked by a peptide bond.
- When treated with sodium chloride, the proteins are salted out of the solution. This process is reversible.
- Water-soluble proteins form colloidal solutions.
- The foaming process is the ability of proteins to form highly concentrated liquid-gas systems called foams.
- Proteins as foaming agents are widely used in the confectionery industry (marshmallow, marshmallow, soufflé).
- The structure of the foam has bread, and this affects its taste properties.
- Place a piece of pressed cottage cheese in a test tube and add a few drops of nitric acid. Heat up carefully.
- Pour into a test tube
- 2 milliliters of egg white, 2 milliliters of concentrated sodium hydroxide solution and a few drops of copper (II) sulfate solution.
- When burning animal proteins, a characteristic smell of "burnt horn" is felt. To a large extent, this smell is determined by the sulfur content in proteins.
- Vegetable proteins - the smell of burnt paper.
- transport
- protective
- catalytic
- structural
- regulatory
- receptor
- motor
- energy
- It consists in binding and delivery (transport) of various substances from one organ to another.
- Hemoglobin combines with oxygen in the lungs, turning into oxyhemoglobin.
- Reaching the organs and tissues with the blood flow, oxyhemoglobin splits and releases oxygen.
- Antibodies neutralize substances that enter the body or appear as a result of the vital activity of bacteria and viruses.
- Plasma protein fibrinogen, participating in blood coagulation, reduces blood loss
- It consists in increasing the speed of various reactions of metabolism and energy in the body.
- Enzyme model
- Hydrolyzed collagen (connective tissue protein)
- Proteins form the basis of the cell structure.
- Regulator protein model (hormone)
- Endocrine glands
- Receptor proteins serve to perceive and transform various signals
- (photoreceptor-rhodopsin).
- Myosin
- actin
- 1 g of protein is equivalent to 17.6 kJ.
- 0.85-1.00 grams per kilogram of weight for an adult (about 100 grams per day for the average man and 70 grams for a woman).
- Children need more protein - up to 1.9 grams per kilogram of body weight per day.
- The study of proteins is important for elucidating the nature of diseases observed in humans and animals.
- Individual proteins are used in the national economy (wool, silk, leather, feathers, hair and horns).
- Breeding of new highly productive breeds of animals and plant varieties.
- Development of directions of modern bioorganic chemistry - genetic engineering and biotechnology
- 1) Proteins are:
- a) artificial fibers c) natural macromolecular compounds
- b) synthetic fibers d) natural low molecular weight compounds
- 2) The minimum protein content is noted in:
- a) intestines b) teeth c) bones d) muscles
- 3) The molecular weight of proteins fluctuates:
- a) from several units to several tens
- b) from several tens to several hundreds
- c) several hundred to several thousand
- d) several thousand to several million
- 4) The composition of proteins does NOT include:
- a) nitrogen b) strontium c) phosphorus d) sulfur
- 5) The protective role of proteins in the body is expressed in:
- a) the implementation of all life processes
- b) delivery of oxygen from the lungs to tissues
- c) acceleration of many chemical reactions
- d) neutralization of foreign substances
- 6) As a result of the hydrolysis of natural proteins, it turns out:
- a) a mixture of 20 amino acids
- b) a mixture of beta-amino acids
- c) a mixture of various alpha-amino acids
- d) a mixture of alpha and beta amino acids
- 7) The primary structure of the protein reflects:
- a) the sequence of connecting amino acid units in the polypeptide chain
- b) the spatial configuration of the polypeptide chain
- c) the volume, shape and relative position of the sections of the polypeptide chain
- d) association of protein molecules
- 8) The secondary structure of the protein is maintained:
- a) covalent polar bonds
- b) hydrogen bonds between >C=O and >NH groups
- c) hydrogen bonds and disulfide bridges
- d) ionic bonds
- 9) The biological activity of a protein molecule is determined by the structure:
- a) primary b) secondary c) tertiary d) quaternary
- 10) Hydrolysis of proteins in the human body occurs under the influence of:
- a) enzymes b) body temperature
- c) ambient temperature d) blood pressure
- Criteria for evaluation:
- no errors - 5
- 2 mistakes - 4
- 3 - 4 errors - 3
- more than 4 errors - 2
- What is the reason for tissue incompatibility during organ transplantation from one organism to another?
- Scientific name for proteins.
- What are protein molecules made of?
- How many protein structures are there?
- The structure of a protein coiled into a spiral?
- What is the quaternary structure of a protein called?
- What is the name of the bond - NH - CO -?
- Destruction of the protein structure.
- Reactions that determine the presence of a protein?
- Foods high in protein.
- The most unstable protein structure?
- Each organism has its own
- individual set of proteins
- proteins
- from amino acid residues
- secondary
- globule
- peptide
- denaturation
- xantoprotein, biuret
- Quaternary
- Well done!
- http://art8you.net/clipart/symbols-arrows/ - pointers
- schoolsetovo.ucoz.ru - flasks
- http://himbio.ucoz.ru/index/illjustracii/0-21 - test tubes
- http://artcity.lv/2007/10/06/klipart-tekhnika-124-izobrazhenija.html - molecule
- http://diterglass.com/page/145/ - water drops
- Chemistry O.S. Gabrielyan, A.G. Ostroumov, Textbook for professions and specialties of the socio-economic profile, M., "Academy" 2011, 256 p.
- Chemistry O.S. Gabrielyan, A.G. Ostroumov, A guide for teachers, M., Academy 2012.