Properties and structure of carbohydrates.

to the human body, as well as other living beings need energy.Without it, no flow of processes is impossible.After all, every biochemical reaction, enzymatic process or any stage of metabolism needs energy source.

Therefore, the value of materials, giving the body strength to life, is very large and important.What is the matter?Carbohydrates, proteins and fats.The structure of each is different, they belong to completely different classes of chemical compounds, but one of their functions is similar - to provide the body with the necessary energy for life.Consider one of the following group of substances - carbohydrates.

Classification

carbohydrate composition and structure of carbohydrates since their opening defined by their name.After all, in the early sources, it was thought that such a group of compounds which are present in the structure of carbon atoms bound to water molecules.

more thorough analysis, as well as the accumulated information about the diversity of the substances permitted to prove that not all representatives are only a part.However, this feature is still one of those that determines the structure of carbohydrates.

modern classification of this group of compounds is as follows:

1. monosaccharides (ribose, fructose, glucose, and so on).
2. oligosaccharides (bios, triose).
3. polysaccharides (starch and cellulose).

also all carbohydrates can be divided into the following major groups:

• restore;
• non-reducing.

structure of carbohydrate molecules in each group take a closer look.

monosaccharides: characteristic

This category includes all simple carbohydrates, which contain an aldehyde (aldose) or ketone (ketose) group and not more than 10 carbon atoms in the structure of chain.If you look at the number of atoms in the main chain, the monosaccharides may be divided into:

• triose (glyceraldehyde);
• tetroses (erythrulose, erythrose);
• pentose (ribose and deoxyribose);
• hexoses (glucose, fructose).

All other representatives are not so important for the body as listed.

avilable molecules

In structure monosaccharides can be presented in the form of a chain or in a cyclic form of carbohydrate.How does this happen?The fact is that the central carbon atom in the compound is an asymmetric center around which the molecule is able to rotate in solution.Since forming optical isomers monosaccharides L- and D-forms.This formula of glucose recorded in a straight chain, you can mentally grasp the aldehyde group (or ketone) and roll into a ball.To obtain the corresponding cyclic formula.

chemical structure of carbohydrates number of monosaccharides is quite simple: a number of carbon atoms that form a chain or ring, each of which are different or are located on one side of the hydroxyl groups and hydrogen atoms.If all like structure on one side, then the D-isomer is formed, if for different interleaved each other - then the L-isomer.If we write the general formula of the common representative of the monosaccharides glucose in molecular form, it would be: C6H12O6.Moreover, the record reflects the structure and fructose, too.After all, these two monosaccharides chemically - structural isomers.Glucose - aldegidospirt, fructose - ketoalcohols.

structure and properties of a number of carbohydrates monosaccharides are closely linked.Because of the presence of aldehyde and ketone group consisting structure they belong to and aldegido- ketonospirtam that determines their chemical nature and the reaction in which they are able to enter.

Thus, glucose exhibits the following chemical properties:

1. The reactions due to the presence of the carbonyl group:

• oxidation - reaction "silver mirror";
• with freshly hydroxide, copper (II) - aldonic acid;
• strong oxidizers are able to form dibasic acids (aldarovye), transforming not only the aldehyde but one hydroxyl group;
• recovery - converted into polyols.

2. The molecule contains hydroxyl groups, and that reflects the structure.The properties of carbohydrates, which are influenced by these groups:

• capacity for alkylated - the formation of ethers;
• acylation - the formation of esters;
• qualitative reaction on copper hydroxide (II).

3. narrowly-specific properties of glucose:

• butyric;
• alcohol;
• lactic fermentation.

Functions in the body

structure and function of a number of carbohydrates monosaccharides are closely related.Recent consist primarily of involvement in biochemical reactions of live organisms.What role is played in this monosaccharides?

1. basis for the production of oligo-and polysaccharides.
2. Pentose (ribose and deoxyribose) - the most important molecules involved in the formation of ATP, RNA, DNA.And they, in turn, the main suppliers of the hereditary material, energy and protein.
3. Concentration glucose in the blood - a true measure of the osmotic pressure and its changes.

oligosaccharides: structure

carbohydrate structure of this group is reduced to the presence of two (Diozu) or three (triose) molecules composed of monosaccharides.There are those in which the composition of 4, 5 or more structures (up to 10), but the most common are disaccharides.That is, upon hydrolysis, such compounds decompose to form glucose, fructose, pentoses, and so on.What compounds belong to this category?A typical example - is sucrose (ordinary sugar cane), lactose (the main component of milk), maltose, lactulose, isomalt.

chemical structure of carbohydrates in this series has the following features:

1. general formula molecular species: S12N22O11.
2. two same or different monosaccharide residues in the disaccharide structure are interconnected by means of bridge glycoside.The nature of this compound will depend on the reducing power of sugar.
3. Reducing disaccharides.Carbohydrate structure of this type is the formation of a bridge between the glycosidic hydroxyl aldehyde and hydroxyl groups of different molecules of monosaccharides.These include maltose, lactose, and so forth.
4. nonrecoverable - a typical example of sucrose - when a bridge is formed between the hydroxyls only those groups, without the involvement of an aldehyde structure.

Thus, the structure of the carbohydrate can be summarized in the form of a molecular formula.If you need detailed detailed structure, it is possible to draw with graphic projections or Fisher formulas Heuorsa.Specifically, two cyclic monomers (monosaccharides) or different or similar (depending on the oligosaccharide) interconnected by a glycosidic bridge.When building should consider restoring the ability to display properly due.

Examples of disaccharide molecules

If the job is in the form: "Note the structural features of carbohydrate", then it is best to first disaccharide specify from what remains of monosaccharides it is.The most common types are:

• sucrose - built from the alpha-beta-glucose and fructose;
• maltose - of the glucose residues;
• cellobiose - consists of two glucose residues of beta-D-form;
• lactose - galactose + glucose;
• lactulose - galactose + fructose and so on.

then the available balances should be the structural formula with a clear prescription of the type of glycoside bridge.

value for living organisms

very large role and disaccharide, it is important not only to the structure.The functions of carbohydrates and fats are generally similar.It is based on the energy component.Nevertheless, for some of the individual disaccharides should indicate their special meaning.

1. Sucrose - the main source of glucose in the human body.
2. Lactose found in breast milk in mammals, including female and 8%.
3. lactulose obtained in the laboratory for use in medical applications, and is also added to dairy products.

Any disaccharide, trisaccharide and so on in humans and other creatures undergoes hydrolysis to form a momentary monosaccharides.It is this feature that underlies the use of this class of carbohydrates in a crude man, unchanged (beet or cane sugar).

Polysaccharides: features molecules

functions, composition and structure of a number of carbohydrates are important for organisms living beings, as well as human activities.First, you should understand what kind of carbohydrates are polysaccharides.

are many of them:

• starch;
• glycogen;
• murein;
• glucomannan;
• cellulose;
• dextrin;
• galactomannan;
• muromin;
• pectin;
• amylose;
• chitin.

This is not an exhaustive list, but only the most important for animals and plants.If you carry out the task "Note the number of the structural features of carbohydrate polysaccharides," the first thing you should pay attention to their spatial structure.This is a very voluminous, giant molecules consisting of hundreds of monomer units, cross-linked to each other by glycosidic chemical bonds.Often the molecular structure of polysaccharides of carbohydrate is a layered composition.

There is a definite classification of such molecules.

1. Gomopolisaharidy - consist of the same repetitive monosaccharide units.Depending on the monosaccharide may be hexose, pentose, and so on (glucans, mannans, galactans).
2. heteropolysaccharide - formed by different monomer units.

to compounds with linear spatial structure should be classified, for example, cellulose.Branched structure has most of polysaccharides - starch, glycogen, chitin and so on.

role in the body of living creatures

Structure and function of carbohydrates in this group are closely connected with the life of all beings.For example, plants in the form of reserve nutrients accumulated in different parts of the shoot or root starch.The main source of energy for animals - besides polysaccharides, which are formed by cleavage of a lot of energy.

Carbohydrates in the structure of cells play a very significant role.From chitin cover it consists of many insects and crustaceans, murein - a component of bacterial cell walls, cellulose - the basis of plants.

reserve nutrients of animal origin - a molecule of glycogen, or as it is more commonly called animal fat.It is stored in separate parts of the body, and performs not only energy, but also a protective function against mechanical influences.

For most organisms is important carbohydrate structure.Biology each animal and plants is such that requires constant energy source, inexhaustible.This can give only they, and most specifically in the form of polysaccharides.Thus, the total 1 g carbohydrate splitting as a result of metabolic processes results in the release of energy of 4.1 kcal!This maximum is no longer provides any one compound.That is why the carbohydrates must be present in the diet of any human and animal.Plants also take care of themselves: the process of photosynthesis, they formed inside starch and store it.

General properties of carbohydrates

structure of fats, proteins and carbohydrates in general similar.After all, they are macromolecules.Even some of their functions have a common origin.It should summarize the role and importance of carbohydrates in the life of the planet's biomass.

1. composition and structure of carbohydrates involve the use of them as building material for the membrane of plant cells, animal and bacterial membranes as well as the formation of intracellular organelles.
2. protective function.Typical for the plant organisms and is manifested in the formation of their spines, thorns, and so on.Plastic
3. role - forming vital molecules (DNA, RNA, ATP and others).
4. receptor function.The polysaccharides and oligosaccharides - active participants in traffic are transported across the cell membrane, "guards", catching effects.
5. Energy the most significant role.It provides maximum energy for all of intracellular processes, as well as the work of the whole organism.
6. regulation of the osmotic pressure - Glucose to exercise such control.
7. Some polysaccharides are food reserves, the source of energy for animal creatures.

thus evident that the structure of fats, proteins and carbohydrates, their function and role in the organisms living systems are critical and decisive importance.These molecules - the creators of life, they also preserve and maintain it.

Carbohydrates with other macromolecular compounds

Also known role of carbohydrates is not in its pure form and in combination with other molecules.These include the most common such as:

• glycosaminoglycans or mucopolysaccharides;
• glycoproteins.

Structure and properties of carbohydrates of this type is rather complicated, because of the complex are connected to a variety of functional groups.The main role of this type of molecules - involved in many life processes of organisms.Representatives are: hyaluronic acid, chondroitin sulfate, heparan, keratan sulfate and others.

There are also polysaccharides complexes with other biologically active molecules.For example, glycoproteins or lipopolysaccharides.Their existence is important in the formation of the immunological reactions, as they are part of cells of the lymphatic system.