Home Useful properties of fruits Essay on carbohydrates and lipids. Proteins, lipids and carbohydrates. Their structure and role in living organisms. The biological role of carbohydrates

Useful properties of fruits

Essay on carbohydrates and lipids. Proteins, lipids and carbohydrates. Their structure and role in living organisms. The biological role of carbohydrates

Carbohydrates are organic compounds formed by three chemical elements - carbon, hydrogen and oxygen. Some also contain nitrogen or sulfur. The general formula for carbohydrates is Сm(H2O)n.

They are divided into three main classes: monosaccharides, oligosaccharides (disaccharides) and polysaccharides.

Monosaccharides are the simplest carbohydrates having 3-10 carbon atoms. Most of the carbon atoms in a monosaccharide molecule are associated with alcohol groups, and one is with an aldehyde or keto group.

Glucose (grape sugar) is found in all organisms, including in human blood, since it is an energy reserve, it is part of sucrose, lactose, maltose, starch, cellulose and other carbohydrates. Fructose (fruit sugar) is found in the highest concentrations in fruits, honey, sugar beet root crops. It not only takes an active part in metabolic processes, but also is part of sucrose.

Monosaccharides - crystalline substances, sweet in taste and highly soluble in water.

To oligosaccharides include carbohydrates formed by several monosaccharide residues. They are mostly also crystalline, highly soluble in water and sweet in taste. Depending on the amount of these residues, there are disaccharides (two monosaccharide residues), trisaccharides (three), etc.

Disaccharides include sucrose, lactose and maltose. sucrose (beet or cane sugar) consists of residues of glucose and fructose, it in found in the storage organs of some plants. There is especially a lot of sucrose in the root of the fruits of sugar beet and sugar cane, from where they are obtained industrially. lactose, or milk sugar,formed by residues of glucose and galactose, found in mother's and cow's milk. Maltose (malt sugar) consists of two glucose residues. It is formed during the breakdown of starch in plant seeds and in the human digestive system.

Polysaccharides are biopolymers whose monomers are monosaccharide residues. These include starch, glycogen, cellulose, chitin, etc. The monomer of these polysaccharides is glucose.

Starch is the basicsa vital reserve substance of plants that accumulates in seeds, fruits, tubers, rhizomes and other storage organs. A qualitative reaction to starch is a reaction with iodine, in which starch turns blue-violet.

Glycogen (animal starch) is a reserve polysaccharide of animals and fungi, which in humans accumulates in the largest quantities in the muscles and liver. Glycogen molecules have a higher degree of branching than starch molecules.

Cellulose or fiber - the main reference polysaccharide of plants. Unbranched cellulose molecules form bundles that are part of the cell walls of plants. It is used in the production of textiles, paper, alcohol and other organic substances.

Chitin is a polysaccharide whose monomer is a nitrogen-containing monosaccharidebased on glucose. It is part of the cell walls of fungi and arthropod shells.

Polysaccharides are powdered substances that are unsweetenedtasteless and insoluble in water.

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Functions of carbohydrates

Carbohydrates perform plastic (construction) in the cell, energygetic, storage and support functions. They form the cell walls of plantsand mushrooms. The energy value of the breakdown of 1 g of carbohydrates is 17.2 kJ. Glucose, fructose, sucrose, starch and glycogen are reserve substances. Carbohydrates canalso be part of complex lipids and proteins, forming glycolipids and glycoproteins.

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Lipids

Lipids is a chemically heterogeneous group of hydrophobic substances. These substances do not dissolve in water, but can dissolve in organic solvents.
They form emulsions in water. Lipids are greasy to the touch, many of them leave characteristic non-drying marks on paper. Along with proteins and carbohydrates, they areone of the main components of cells. The content of lipids in different cells is not the same, especially in the seeds and fruits of some plants, in the liver and heart.

By chemical structure, lipids are divided into fats, waxes, steroids, phospholipids, glycolipids, etc.

Fats, or triacylglycerols,are esters of the trihydric alcohol glycerol and higher fatty acids. The fat molecule has dual properties, since the glycerol residue forms a hydrophilic “head”, and fatty acid residues form hydrophobic “tails”.

Most fatty acids contain 14–22 carbonnative atom. Among them there are both saturated andand unsaturated, that is, containing double bonds.

Steroids have molecules with multiple cycles. These include an obligatory component of cell membranes - cholesterol (cholesterol), hormones estradiol and testosterone. ron, vitamin D.

Phospholipids - polar lipids. In addition to glycerol and fatty acid residues, theyhave a phosphoric acid residue. Phospholipids are the basis of cell membranes and provide their barrier properties.

Waxes are esters of higher fatty acids and high molecular weight alcohols. In plants, they form a film on the surface of organs - leaves, fruits. These connectionsprotect the ground organs of plants from excessive loss of moisture, prevent the penetration of pathogens, etc. In insects, they cover the body or serve to build honeycombs.

Glycolipids are also components of membranes, but their content there is low.The non-lipid portion of glycolipids includes a carbohydrate residue.

Functions of lipids.

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Reserve - fats are deposited in the stock in the tissues of vertebrates.

Energy - half of the energy consumed by the cells of vertebrates at rest is formed as a result of fat oxidation. Fats are also used as a source of water. The energy effect from the breakdown of 1 g of fat is 39 kJ, which is twice the energy effect from the breakdown of 1 g of glucose or protein.
Protective - the subcutaneous fat layer protects the body from mechanical damage.
Structural Phospholipids are part of cell membranes.
Thermal insulation - subcutaneous fat helps to keep warm.
electrical insulating - myelin, secreted by Schwann cells (form the sheaths of nerve fibers), isolates some neurons, which many times accelerates the transmission of nerve impulses.
Nutritious - Some lipid-like substances contribute to building muscle mass, maintaining body tone.
Lubricating Waxes cover the skin, wool, feathers and protect them from water. The leaves of many plants are covered with a wax coating; wax is used in the construction of honeycombs.
Hormonal - adrenal hormone - cortisone and sex hormones are lipid in nature.

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THEMATIC ASSIGNMENTS

Part A

A1. A polysaccharide monomer can be:
1) amino acid
2) glucose
3) nucleotide
4) cellulose

A2. In animal cells, the storage carbohydrate is:
1) cellulose
2) starch
3) chitin
4) glycogen

A3. Most energy is released during splitting:
1) 10 g protein
2) 10 g glucose
3) 10 g fat
4) 10 g amino acid

A4. What function do lipids not perform?
1) energy
2) catalytic
3) insulating
4) storage

A5. Lipids can be dissolved in:
1) water
2) salt solution
3) hydrochloric acid
4) acetone

Part B

IN 1. Select the features of the structure of carbohydrates
1) consist of amino acid residues
2) consist of glucose residues
3) consist of hydrogen, carbon and oxygen atoms
4) some molecules have a branched structure
5) consist of fatty acid residues and glycerol
6) consist of nucleotides

IN 2. Select the functions that carbohydrates perform in the body
1) catalytic
2) transport
3) signal
4) building
5) protective
6) energy

VZ. Select the functions that lipids perform in the cell
1) structural
2) energy
3) storage
4) enzymatic
5) signal
6) transport

AT 4. Match the group of chemical compounds with their role in the cell:

ROLE OF THE COMPOUND IN THE CELL	COMPOUND
A) quickly split with the release of energy B) are the main reserve substance of plants and animals C) are a source for the synthesis of hormones D) form a heat-insulating layer in animals D) are a source of additional water for camels E) are part of the integument of insects	1) carbohydrates 2) lipids

Part C

C1. Why does not glucose accumulate in the body, but starch and glycogen accumulate?

Test 2

Part 1 contains 10 tasks (A1-10). Each question has 4 possible answers, one of which is correct.

Part 1

A 1. Monosaccharide, the molecule of which contains five carbon atoms

1. glucose

2. fructose

3. galactose

4. deoxyribose

A 2. Chemical bond connecting the residues of glycerol and higher fatty acids in a fat molecule

1. covalent polar

2. covalent non-polar

4. hydrogen

A 3. The monomer of starch and cellulose is

1. glucose

2. glycerin

3. nucleotide

4. amino acid

A 4. Which of the substances will dissolve lipids

3. physiological saline

4. hydrochloric acid

A 5. Winter hardiness of plants increases with accumulation in cells:

1. starch

3. sugars

4. mineral salts

A 6. What foods contain the most carbohydrates needed by a person?

1. in cheese and cottage cheese

2. bread and potatoes

3. meat and fish

4. vegetable oil

A 7. The end products of glycogen in the cell are

1. ATP and water

2. oxygen and carbon dioxide

3. water and carbon dioxide

4. ATP and oxygen

A 8. The reserve carbohydrate in the animal cell is

1. starch

2. glycogen

3. cellulose

A 9. Juice that does not contain enzymes, but facilitates the absorption of fats in the small intestine

1. gastric juice

2. pancreatic juice

3. intestinal juice

A 10. In humans, food carbohydrates begin to be digested in

1. duodenum

2. oral cavity

3. stomach

4. large intestine

Part 2 contains 8 tasks (B1-B8): 3 - with the choice of three correct answers out of six, 3 - for correspondence, 2 - for establishing the sequence of biological processes, phenomena, objects.

Part 2

B 1. Lipids found only in animals

1. cholesterol

2. lipoproteins

3. triglycerides

4. phospholipids

5. bile acids

6. testosterone

B 2. Monosaccharides are

2. sucrose

3. lactose

4. glucose

5. maltose

6. galactose

IN 3. Complex organic compounds, the molecule of which includes a carbohydrate component

1. ribonucleotides

2. phospholipids

3. deoxyribonucleotides

4. amino acids

5. adenosine triphosphate

6. cholesterol

B 4. Forms of carbohydrates in plant and animal cells

Cell Carbohydrate

A) plant cells 1. glycogen

B) animal cells 2. starch

3. cellulose

4. heparin

B 5. Establish a correspondence between the characteristic and organic matter

Characteristic Organic matter

1. Composed of carbon, hydrogen and oxygen A. Carbohydrates

2. Low thermal conductivity B. Fats

3. Form biopolymers - polysaccharides

4. Provide interaction of cells of the same type

5. They are all non-polar

6. Practically insoluble in water

B 6. Establish a correspondence between a carbohydrate and the group of carbohydrates to which they belong

Carbohydrate name Carbohydrate group

1. Glucose A. monosaccharides

2. Sucrose B. Disaccharides

3. Galactose B. Polysaccharides

4. Starch

5. Maltose

6. Lactose

B 7. Arrange monosaccharides in ascending order of the number of carbon atoms in their molecule

1. dihydroxyacetone (ketose)

2. glucose

3. elythrose threose

5. glucosamine

6. Frame-O

B 8. Arrange fats in ascending order of carbon atoms in their molecule

1. tripalmitin

2. tristearin

3. trilaurin

4. tricaprylin

5. trimyristin

Part 3 contains 6 tasks. For task C1, give a short free answer, and for tasks C2-C6 - a full detailed answer.

Part 3

С 1. What role do phospholipids and glycolipids play for living organisms?

C 2. Indicate the numbers of proposals in which errors were made. Explain them.

1. Carbohydrates are compounds of carbon and hydrogen.

2. There are three classes of carbohydrates - monosaccharides, disaccharides and polysaccharides.

3. The most common monosaccharides are sucrose and lactose.

4. They are water soluble and have a sweet taste.

5. When 1 g of glucose is broken down, 35.2 kJ of energy is released

C 3. What are the functions of carbohydrates in plant cells?

C 4. Explain why the storage function is performed by polysaccharides, and not monosaccharides?

Answers:

Part 1

A1-4 A6-2

A2-1 A7-3

A3-1 A8-2

A4-2 A9-4

A5-3 A10-2

Part 2

B1-1 3 4

B2-1 4 6

B3-1 3 5

B4 -A 2 3, B 1 4

B5-A 1 3 4, B 2 5 6

V6-A1 3, B 2 5 6, V 4

B7-1 3 4 2 5 6

B8-4 3 5 1 2

Part 3

C 1. Phospholipids and glycolipids are components of cell membranes.

C 2. 1. carbon and water.

3. disaccharides.

5. 17.6 kJ

C 3. 1. Monosaccharides and disaccharides perform an energy function.

2. Starch is a reserve nutrient.

3. Cellulose is part of the cell walls.

C 4. 1. Since polysaccharides are insoluble in water, they do not have an osmotic and chemical effect on the cell.

2. In the solid and dehydrated state, they have a smaller volume and a larger useful mass.

3. Less accessible to pathogenic bacteria and fungi, since these organisms absorb food rather than swallow it.

4. If necessary, they are easily converted into monosaccharides.

Lipids- these are organic substances that do not dissolve in water, but dissolve in organic solvents.

Lipids are divided into:

1. Fats and oils (esters of trihydric alcohol glycerol and fatty acids). Fatty acids are saturated (palmitic, stearic, arachidic) and unsaturated (oleic, linoleic, linolenic). In oils, the proportion of unsaturated fatty acids is higher, so at room temperature they are in a liquid state. The fats of polar animals, compared with tropical animals, also contain more unsaturated fatty acids.

2. Lipoids (fat-like substances). These include: a) phospholipids, b) fat-soluble vitamins (A, D, E, K), c) waxes, d) simple lipids that do not contain fatty acids: steroids (cholesterol, adrenal hormones, sex hormones) and terpenes ( gibberellins - plant growth hormones, carotenoids - photosynthetic pigments, menthol).

Phospholipids have polar heads (hydrophilic regions) and non-polar tails (hydrophobic regions). Due to this structure, they play an important role in the formation of biological membranes.

Lipid functions:

1) energy - fats are a source of energy in the cell. When splitting 1 gram, 38.9 kJ of energy is released;

2) structural (construction) - phospholipids are part of biological membranes;

3) protective and heat-insulating - subcutaneous fatty tissue, protects the body from hypothermia and injuries;

4) storage - fats make up a supply of nutrients, being deposited in the fat cells of animals and in the seeds of plants;

5) regulatory - steroid hormones are involved in the regulation of metabolism in the body (hormones of the adrenal cortex, sex hormones).

6) water source - when 1 kg of fat is oxidized, 1.1 kg of water is formed. It is used by desert animals, so a camel can go without drinking for 10-12 days.

Carbohydrates - complex organic substances, the general formula of which is C n (H 2 O) m. They are made up of carbon, hydrogen and oxygen. In animal cells they contain 1-2%, and in plant cells up to 90% of the mass of dry matter.

Carbohydrates are divided into monosaccharides, oligosaccharides and polysaccharides.

Monosaccharides, depending on the number of carbon atoms, are divided into trioses (C 3), tetroses (C 4), pentoses (C 5), hexoses (C 6), etc. An important role in the life of the cell is played by:

1) Pentoses. Ribose and deoxyribose are constituents of nucleic acids.

2) Hexoses: glucose, fructose, galactose. Fructose is found in many fruits and honey, contributing to their sweet taste. Glucose is the main energy material in the cell during metabolism. Galactose is part of milk sugar (lactose).

D:\Program Files\Physicon\Open Biology 2.6\content\3DHTML\08010203.htm

Maltose

Oligosaccharide molecules are formed during the polymerization of 2-10 monosaccharides. When two monosaccharides are combined, disaccharides are formed: sucrose, consisting of glucose and fructose molecules; lactose, consisting of glucose and galactose molecules; Maltose is made up of two glucose molecules. In oligosaccharides and polysaccharides, monomer molecules are connected by glycosidic bonds.

Polysaccharides are formed during the polymerization of a large number of monosaccharides. Polysaccharides include glycogen (the main storage substance in animal cells); starch (the main storage substance in plant cells); cellulose (found in the cell walls of plants), chitin (found in the cell wall of fungi). The monomer of glycogen, starch and cellulose is glucose.

D:\Program Files\Physicon\Open Biology 2.6\content\3DHTML\08010208.htmCellulose

Functions of carbohydrates:

1) energy - carbohydrates are the main source of energy in the cell. When splitting 1 gram of carbohydrates, 17.6 kJ of energy is released.

2) structural (construction) - shells of plant cells are built from cellulose.

3) storage - polysaccharides serve as a reserve nutrient material.

Squirrels are biological polymers whose monomers are amino acids. Proteins are very important for cell life. They make up 50-80% of the dry matter of an animal cell. Proteins contain 20 different amino acids. Amino acids are divided into interchangeable, which can be synthesized in the human body, and irreplaceable (methionine, tryptophan, lysine, etc.). Essential amino acids cannot be synthesized by the human body and must be obtained from food.

Amino acid

Depending on the properties of the radical, amino acids are divided into three groups: non-polar, polar charged and polar uncharged.

Amino acids are linked together by an NH-CO bond (covalent, peptide bond). Compounds of several amino acids are called peptides. Depending on their number, di-, tri-, oligo- or polypeptides are distinguished. Typically, proteins contain 300-500 amino acid residues, but there are also larger ones containing up to several thousand amino acids. Differences in proteins are determined not only by the composition and number of amino acids, but also by the sequence of their alternation in the polypeptide chain. Levels of organization of protein molecules:

1) the primary structure is the sequence of amino acids in the polypeptide chain. Amino acids are linked by peptide bonds. The primary structure is specific to each protein and is determined by the amino acid sequence encoded in the DNA. Replacement only
one amino acid leads to a change in the functions of the protein.

2) the secondary structure is twisted into a spiral (α - spiral) or laid in the form of an accordion (β - layer) polypeptide chain. The secondary structure is supported by hydrogen bonds.

3) tertiary structure - a spiral laid in space, forming a globule or fibril. The protein is active only in the form of a tertiary structure. It is supported by disulfide, hydrogen, hydrophobic and other bonds.

4) quaternary structure - is formed by combining several proteins with primary, secondary and tertiary structures. For example, the blood protein hemoglobin consists of four globin protein molecules and a non-protein part, which is called heme.

Proteins are either simple (proteins) or complex (proteins). Simple proteins are made up of only amino acids. Complex ones contain, in addition to amino acids, other chemical compounds (for example: lipoproteins, glycoproteins, nucleoproteins, hemoglobin, etc.).

When the protein is exposed to various chemicals, high temperature, the structure of the protein is destroyed. This process is called denaturation. The process of denaturation is sometimes reversible, that is, spontaneous restoration of the protein structure can occur - renaturation. Renaturation is possible when the primary structure of the protein is preserved.

Protein Functions:

1. Structural (building) function - proteins are part of all cell membranes and cell organelles.

2. Catalytic (enzymatic) - enzyme proteins accelerate chemical reactions in the cell.

3. Motor (contractile) - proteins are involved in all types of cell movements. Thus, muscle contraction is provided by contractile proteins: actin and myosin.

4. Transport - proteins transport chemicals. So, the protein hemoglobin carries oxygen to organs and tissues.

5. Protective - blood proteins antibodies (immunoglobulins) recognize antigens alien to the body and contribute to their destruction.

6. Energy - proteins are the source of energy in the cell. When splitting 1 gram of proteins, 17.6 kJ of energy is released.

7. Regulatory - proteins are involved in the regulation of metabolism in the body (hormones insulin, glucagon).

8. Receptor - proteins underlie the work of receptors.

9. Storage - albumin proteins are reserve proteins of the body (egg white contains ovalbumin, milk contains lactalbumin).

Lipids. Carbohydrates.

In addition to inorganic substances and their ions, all cellular structures also consist of organic compounds - proteins, lipids, carbohydrates and nucleic acids.

carbohydrates and lipids.

Carbohydrates (sugars) are bioorganic compounds of carbon and water that are part of all living organisms: The general formula is Cn (H2O) n.

Water-soluble carbohydrates.

Monosaccharides:

glucose is the main source of energy for cellular respiration;

fructose - an integral part of the nectar of flowers and fruit juices;

ribose and deoxyribose are structural elements of nucleotides, which are monomers of RNA and DNA;

disaccharides :

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

lactose (glucose-N-galactose) - is part of the milk of mammals;

maltose (glucose + glucose) is a source of energy in germinating seeds.

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

Water insoluble carbohydrates:

Starch is a mixture of two polymers: amylose and amylopectin. A branched spiralized molecule that serves as a reserve substance in plant tissues;

Cellulose (cellulose) is a polymer consisting of several straight parallel chains connected by hydrogen bonds. This structure prevents the penetration of water and ensures the stability of the cellulose membranes of plant cells;

Chitin is the main structural element of the integument of arthropods and the cell walls of fungi;

Glycogen is the reserve substance of an animal cell. The monomer is a-glucose.

Functions of insoluble carbohydrates: structural, storage, energy, protective.

Lipids- organic compounds, most of which are esters of glycerol and fatty acids.

Insoluble in water, but soluble in non-polar solvents. Present in all cells. Lipids are made up of hydrogen, oxygen and carbon atoms.

Types of lipids: fats, waxes, phospholipids, steroids.

Functions of lipids :

Storage - fats are deposited in the reserve in the tissues of vertebrates;

Energy - half of the energy consumed by the cells of vertebrates at rest is formed as a result of fat oxidation. Fats are also used as a source of water

Protective - the subcutaneous fat layer protects the body from mechanical damage;

Structural - phospholipids are part of cell membranes;

Thermal insulation - subcutaneous fat helps to keep warm;

Electrical insulating - myelin, secreted by Schwann cells, isolates some neurons, which many times accelerates the transmission of nerve impulses;

Nutrient - bile acids and vitamin D are formed from steroids;

Lubricating - waxes cover the skin, wool, feathers and protect them from water. The leaves of many plants are covered with a wax coating; wax is used in the construction of honeycombs;

Hormonal - adrenal hormone - cortisone - and sex hormones are lipid in nature. Their molecules do not contain fatty acids.

Carbohydrates are organic compounds, the composition of which in most cases is expressed by the general formula C n(H2O) m (n And m≥ 4). Carbohydrates are divided into monosaccharides, oligosaccharides and polysaccharides.

Monosaccharides are simple carbohydrates, depending on the number of carbon atoms, they are divided into trioses (3), tetroses (4), pentoses (5), hexoses (6) and heptoses (7 atoms). The most common are pentoses and hexoses. Properties of monosaccharides - easily soluble in water, crystallize, have a sweet taste, can be presented in the form of α- or β-isomers.

Ribose and deoxyribose belong to the group of pentoses, are part of the RNA and DNA nucleotides, ribonucleoside triphosphates and deoxyribonucleoside triphosphates, etc. Deoxyribose (C 5 H 10 O 4) differs from ribose (C 5 H 10 O 5) in that at the second carbon atom it has a hydrogen atom, not a hydroxyl group like ribose.

Glucose or grape sugar(C 6 H 12 O 6), belongs to the group of hexoses, can exist in the form of α-glucose or β-glucose. The difference between these spatial isomers lies in the fact that at the first carbon atom in α-glucose the hydroxyl group is located under the plane of the ring, while in β-glucose it is above the plane.

Glucose is:

one of the most common monosaccharides,

the most important source of energy for all types of work occurring in the cell (this energy is released during the oxidation of glucose during respiration),

monomer of many oligosaccharides and polysaccharides,

an essential component of blood.

Fructose or fruit sugar, belongs to the group of hexoses, sweeter than glucose, found in free form in honey (more than 50%) and fruits. It is a monomer of many oligosaccharides and polysaccharides.

Oligosaccharides- carbohydrates formed as a result of a condensation reaction between several (from two to ten) monosaccharide molecules. Depending on the number of monosaccharide residues, disaccharides, trisaccharides, etc. are distinguished. Disaccharides are the most common. Properties of oligosaccharides- dissolve in water, crystallize, the sweet taste decreases as the number of monosaccharide residues increases. The bond formed between two monosaccharides is called glycosidic.

Sucrose or cane or beet sugar, is a disaccharide consisting of glucose and fructose residues. Found in plant tissues. Is a food product (common name - sugar). In industry, sucrose is produced from sugar cane (stems contain 10–18%) or sugar beets (root crops contain up to 20% sucrose).

Maltose or malt sugar, is a disaccharide consisting of two glucose residues. Present in germinating seeds of cereals.

Lactose or milk sugar, is a disaccharide consisting of glucose and galactose residues. It is present in the milk of all mammals (2–8.5%).

Polysaccharides- these are carbohydrates formed as a result of the polycondensation reaction of a multitude (several tens or more) of monosaccharide molecules. Properties of polysaccharides- do not dissolve or dissolve poorly in water, do not form clearly formed crystals, do not have a sweet taste.

Starch(C 6 H 10 O 5) n- a polymer, the monomer of which is α-glucose. Starch polymer chains contain branched (amylopectin, 1,6-glycosidic bonds) and unbranched (amylose, 1,4-glycosidic bonds) sections. Starch - the main reserve carbohydrate of plants, is one of the products of photosynthesis, accumulates in seeds, tubers, rhizomes, bulbs. The starch content in rice grains is up to 86%, wheat - up to 75%, corn - up to 72%, in potato tubers - up to 25%. Starch is the main carbohydrate human food (digestive enzyme - amylase).

Glycogen(C 6 H 10 O 5) n- a polymer, the monomer of which is also α-glucose. The polymeric chains of glycogen resemble the amylopectin sections of starch, but unlike them, they branch even more strongly. Glycogen is the main reserve carbohydrate of animals, in particular humans. Accumulates in the liver (content - up to 20%) and muscles (up to 4%), is a source of glucose.

Cellulose(C 6 H 10 O 5) n- a polymer, the monomer of which is β-glucose. Cellulose polymer chains do not branch (β-1,4-glycosidic bonds). The main structural polysaccharide of plant cell walls. The cellulose content in wood is up to 50%, in the fibers of cotton seeds - up to 98%. Cellulose is not broken down by human digestive juices, because. it lacks the enzyme cellulase, which breaks bonds between β-glucoses.

Inulin- a polymer whose monomer is fructose. Reserve carbohydrate of plants of the Compositae family.

Glycolipids- complex substances formed as a result of the combination of carbohydrates and lipids.

Glycoproteins- complex substances formed as a result of the combination of carbohydrates and proteins.

Functions of carbohydrates

Function	Examples and explanations
Energy	The main source of energy for all kinds of work occurring in cells. When splitting 1 g of carbohydrates, 17.6 kJ are released.
Structural	Cellulose is the cell wall of plants, murein is the cell wall of bacteria, chitin is the cell wall of fungi and the integuments of arthropods.
Reserve	The reserve carbohydrate in animals and fungi is glycogen, in plants - starch, inulin.
Protective	Mucus protects the intestines, bronchi from mechanical damage. Heparin prevents blood clotting in animals and humans.

See here an animation about the classification and biological functions of carbohydrates

The structure and function of lipids

Lipids do not have a single chemical characteristic. In most benefits, giving lipid determination, they say that this is a combined group of water-insoluble organic compounds that can be extracted from the cell with organic solvents - ether, chloroform and benzene. Lipids can be divided into simple and complex.

Simple lipids the majority are esters of higher fatty acids and trihydric alcohol glycerol - triglycerides. Fatty acid have: 1) the same grouping for all acids - a carboxyl group (–COOH) and 2) a radical by which they differ from each other. The radical is a chain of a different number (from 14 to 22) groups -CH 2 -. Sometimes a fatty acid radical contains one or more double bonds (–CH=CH–), such fatty acid is called unsaturated. If a fatty acid has no double bonds, it is called rich. In the formation of triglyceride, each of the three hydroxyl groups of glycerol undergoes a condensation reaction with a fatty acid to form three ester bonds.

If triglycerides are dominated by saturated fatty acids, then at 20°C they are solid; they are called fats, they are characteristic of animal cells. If triglycerides are dominated by unsaturated fatty acids, then at 20 ° C they are liquid; they are called oils, they are characteristic of plant cells.

1 - triglyceride; 2 - ester bond; 3 - unsaturated fatty acid; 4 - hydrophilic head; 5 - hydrophobic tail.

The density of triglycerides is lower than that of water, so they float in water, are on its surface.

Simple lipids also include waxes- esters of higher fatty acids and macromolecular alcohols (usually with an even number of carbon atoms).

Complex lipids. These include phospholipids, glycolipids, lipoproteins, etc.

Phospholipids- triglycerides in which one fatty acid residue is replaced by a phosphoric acid residue. They take part in the formation of cell membranes.

Glycolipids- see above.

Lipoproteins- complex substances formed as a result of the combination of lipids and proteins.

Lipoids- fat-like substances. These include carotenoids (photosynthetic pigments), steroid hormones (sex hormones, mineralocorticoids, glucocorticoids), gibberellins (plant growth substances), fat-soluble vitamins (A, D, E, K), cholesterol, camphor, etc.

See here an animation about the classification and biological functions of lipids

Functions of lipids

Function	Examples and explanations
Energy	The main function of triglycerides. When splitting 1 g of lipids, 38.9 kJ are released.
Structural	Phospholipids, glycolipids and lipoproteins are involved in the formation of cell membranes.
Reserve	Fats and oils are a reserve food substance in animals and plants. Important for animals that hibernate during the cold season or make long transitions through areas where there are no food sources. Plant seed oils are needed to provide energy to the seedling.
Protective	Layers of fat and fatty capsules provide shock absorption of internal organs. Layers of wax are used as a water-repellent coating in plants and animals.
Thermal insulation	Subcutaneous fatty tissue prevents the outflow of heat into the surrounding space. Important for aquatic mammals or mammals living in cold climates.
Regulatory	Gibberellins regulate plant growth. The sex hormone testosterone is responsible for the development of male secondary sexual characteristics. The sex hormone estrogen is responsible for the development of female secondary sexual characteristics and regulates the menstrual cycle. Mineralocorticoids (aldosterone, etc.) control water-salt metabolism. Glucocorticoids (cortisol, etc.) are involved in the regulation of carbohydrate and protein metabolism.
Source of metabolic water	When 1 kg of fat is oxidized, 1.1 kg of water is released. Important for desert dwellers.
catalytic	Fat-soluble vitamins A, D, E, K are enzyme cofactors, i.e. by themselves, these vitamins do not have catalytic activity, but without them, enzymes cannot perform their functions.

Carbohydrates- organic compounds, the composition of which in most cases is expressed by the general formula C n(H2O) m (n And m≥ 4). Carbohydrates are divided into monosaccharides, oligosaccharides and polysaccharides.

Monosaccharides- simple carbohydrates, depending on the number of carbon atoms, are divided into trioses (3), tetroses (4), pentoses (5), hexoses (6) and heptoses (7 atoms). The most common are pentoses and hexoses. Properties of monosaccharides- easily soluble in water, crystallize, have a sweet taste, can be presented in the form of α- or β-isomers.

Ribose and deoxyribose belong to the group of pentoses, are part of the RNA and DNA nucleotides, ribonucleoside triphosphates and deoxyribonucleoside triphosphates, etc. Deoxyribose (C 5 H 10 O 4) differs from ribose (C 5 H 10 O 5) in that it has a hydrogen atom at the second carbon atom, not a hydroxyl group like ribose.

Glucose or grape sugar(C 6 H 12 O 6), belongs to the group of hexoses, can exist in the form of α-glucose or β-glucose. The difference between these spatial isomers is that at the first carbon atom in α-glucose the hydroxyl group is located under the plane of the ring, while in β-glucose it is above the plane.

Glucose is:

one of the most common monosaccharides,
the most important source of energy for all types of work occurring in the cell (this energy is released during the oxidation of glucose during respiration),
monomer of many oligosaccharides and polysaccharides,
an essential component of blood.

Sucrose or cane or beet sugar, is a disaccharide consisting of glucose and fructose residues. Found in plant tissues. It is a food product (common name - sugar). In industry, sucrose is produced from sugar cane (stems contain 10-18%) or sugar beets (root crops contain up to 20% sucrose).

Maltose or malt sugar, is a disaccharide consisting of two glucose residues. Present in germinating seeds of cereals.

Lactose or milk sugar, is a disaccharide consisting of glucose and galactose residues. Present in the milk of all mammals (2-8.5%).

Starch(C 6 H 10 O 5) n is a polymer whose monomer is α-glucose. Starch polymer chains contain branched (amylopectin, 1,6-glycosidic bonds) and unbranched (amylose, 1,4-glycosidic bonds) sections. Starch is the main reserve carbohydrate of plants, is one of the products of photosynthesis, accumulates in seeds, tubers, rhizomes, bulbs. The starch content in rice grains is up to 86%, wheat - up to 75%, corn - up to 72%, in potato tubers - up to 25%. Starch is the main carbohydrate human food (digestive enzyme - amylase).

(C 6 H 10 O 5) n is a polymer whose monomer is β-glucose. Cellulose polymer chains do not branch (β-1,4-glycosidic bonds). The main structural polysaccharide of plant cell walls. The cellulose content in wood is up to 50%, in the fibers of cotton seeds - up to 98%. Cellulose is not broken down by human digestive juices, because. it lacks the enzyme cellulase, which breaks bonds between β-glucoses.

Inulin is a polymer whose monomer is fructose. Reserve carbohydrate of plants of the Compositae family.

Glycolipids- complex substances formed as a result of the combination of carbohydrates and lipids.

Glycoproteins- complex substances formed as a result of the combination of carbohydrates and proteins.

Functions of carbohydrates

The structure and function of lipids

Simple lipids in the majority are esters of higher fatty acids and trihydric alcohol glycerol - triglycerides. Fatty acid have: 1) the same grouping for all acids - a carboxyl group (-COOH) and 2) a radical by which they differ from each other. The radical is a chain of various numbers (from 14 to 22) groups -CH 2 -. Sometimes the fatty acid radical contains one or more double bonds (-CH=CH-), such fatty acid is called unsaturated. If a fatty acid has no double bonds, it is called rich. In the formation of triglyceride, each of the three hydroxyl groups of glycerol undergoes a condensation reaction with a fatty acid to form three ester bonds.

If triglycerides are dominated by saturated fatty acids, then at 20°C they are solid; they are called fats, they are characteristic of animal cells. If triglycerides are dominated by unsaturated fatty acids, then at 20 °C they are liquid; they are called oils, they are characteristic of plant cells.

1 - triglyceride; 2 - ester bond; 3 - unsaturated fatty acid;
4 - hydrophilic head; 5 - hydrophobic tail.