The properties of carbohydrates.

in wildlife are common, many substances, the value of which is difficult to overestimate.For example, these include carbohydrates.They are extremely important as a source of energy for animals and humans, and some properties of carbohydrates making them an indispensable raw material for industry.

What is it?It

substance whose structure can be described by the formula Cn (H2O) m.They have great biological significance, play a crucial role in the lives of many living beings.

name of this group of scientists have come up after the initial analysis has been made of substances that it contains.Then it was found that their main components are carbon and water.It later turned out that the name came to be extremely precise, since the properties of carbohydrates such that the ratio of hydrogen and oxygen atoms in them is completely identical to that of water.Simply put, the two hydrogen atoms there is one oxygen.The first Russian version of the name was suggested in 1844 by Professor K. Schmidt.

Some additions

If slightly modify the above formula, relegate «n» of the brackets, the expression will be slightly different: See (H2O) n.Perhaps, it perfectly reflects the essence of the name "coal - water."

To date, scientists have firmly established that there are a number of substances that have properties of carbohydrates, but not quite correspond to the formula described by us.And because foreign literature one can often come across the word "glycidyl", which is synonymous with modern, 1844, which was not quite accurate.

simple classification

whole huge class of materials can be divided into two groups: simple and complex glycidyl.What are the properties of carbohydrates that occur in them?Actually, they also are not very complicated:

• simply referred to as the substances from the group which are not amenable to hydrolysis with subsequent formation of other carbohydrates.The main difference is that the number of oxygen atoms in their structure still similar number of carbon atoms.They called monosaccharides.
• Accordingly, the definition of "complex" includes all those glycidyl which on hydrolysis decompose to form a plurality of simple carbohydrates.Of course, they have the ratio of carbon and oxygen atoms varies.They called disaccharide.A very important role in the nature of play is complex carbohydrates, a list of which we partially present in the article.

In addition, there is another classification by which carbohydrates are divided into three types.Here they are:

• monosaccharides.
• oligosaccharides.
• polysaccharides.

table below certain carbohydrates will help you to deal with their major differences.

Of course, we were shown a short table of carbohydrates, but its scope is simply impossible to fit all the specific features that are peculiar to some members of this vastclass.And because the main groups analyze each separately, elaborated on some of the properties of the individual, the most common substances.So, what are the classes of carbohydrates?

monosaccharides

should remember that they all belong to the category of solids, easily able to switch to a crystalline state.They are extremely hygroscopic, well soluble in water to form a syrup.Select them in the form of crystals, there is very difficult.Solutions have their neutral reaction, often sweetish taste.The intensity of taste varies: for example, fructose is about 3-3.5 times sweeter than the most frequent glucose.About

structural form

All of these substances - a compound of bifunctional structure, which structure is required to include the carbon skeleton, a carbonyl group and several hydroxyl.If the role of the carbonyl group of the aldehyde group appears, a substance called aldose.Accordingly, in the case of ketone "tail" they called ketosis.

Since in nature, these substances are extremely common and can be found both in their free state or in the form of anhydrite forms.In general, almost all the complex carbohydrates in varying degrees, are anhydrides of simple sugars, which are quite simply obtained by taking away a few (or one) of water molecules (the prefix "en" - no).

Glucose is the most typical representative of this formula

most typical representative of his group - C6H12O6.Very often these carbohydrates found in plant cells.It has not only widespread, but also very important for the body because it is a major source of energy for him (talking about animals and humans, of course).Basically, these are the general properties of proteins, carbohydrates and fats of animal organisms.In addition, widely used in medicine, veterinary medicine, industry (including food).

physical properties

What are the general physical properties of carbohydrates in this group?Appearance - fine white crystals, sweetish taste, well soluble in water.Solubility increases sharply if the solution is heated: in such manner the glucose syrup.

Brief information on the chemical structure of

If you look at the linear formula, the composition of the carbohydrate aldehyde clearly visible one and five hydroxyl groups.When the material is in the crystalline state, the molecules it may be in one of two forms (α- or β-glucose).The fact that the hydroxyl group is coupled to a fifth carbon atom can be reacted with a carbonyl moiety.

prevalence in natural conditions

Since its very much in grape juice, glucose is often referred to as "grape sugar."Under this name it is still known our ancestors.However, it is possible to find in any other sweet fruits or vegetables, in the soft tissues of the plant.In the animal world it is no lower prevalence: about 0.1% of our blood - this is glucose.Furthermore, these carbohydrates can be found in the cell almost any internal organ.But especially a lot of them in the liver, as this is where processing is carried out of glucose into glycogen.

It is (as we have already said) is a valuable source of energy for our body, it is a part of almost all complex carbohydrates.Like other simple carbohydrates, in nature it occurs after the reaction of photosynthesis, which occurs only in the cells of plant organisms:

6SO2 + 6H2O chlorophyll C6H12O6 + 6O2 - Q

plants while performing an incredibly important biosphere function, accumulating energy, which turnsthem from the sun.As for the industrial environment, the grape sugar since ancient times prepared from starch, producing its hydrolysis, the reaction catalyst is concentrated sulfuric acid:

(S6N10O5) n + nH2O H2SO4, t nC6H12O6

chemical properties

What are the chemical properties of carbohydrates of this type?Enjoy all the same characteristics, which are peculiar exclusively alcohols and aldehydes.Furthermore, there have some specific features.First synthesis of simple carbohydrates (including glucose) was produced by talented chemist AM Butlerova in 1861, in which he used as a raw material formaldehyde splitting it in the presence of calcium hydroxide.The formula of this process:

6NSON ------- & gt; C6H12O6

And now look at some of the properties of the other two members of the group, the natural meaning of which is not less great, and because their study biology.Carbohydrates play these species in our daily life is very important.

Fructose

Formula isomer of glucose - SeN12Ob.Like the "ancestor" may exist in linear and cyclic form.Comes in all reactions that are characteristic of polyhydric alcohols, but, thus differing from glucose, it does not react with the ammonia solution of silver oxide.

Ribose

extremely great interest ribose and deoxyribose.If you remember a little program for biology, and know very well that these carbohydrates in the body are part of DNA and RNA, without which the very existence of life on the planet impossible.The name "deoxyribose" means that its molecule at least one oxygen atom (when compared to its normal ribose).Being similar in this respect to glucose may also have a linear and a cyclic structure.

disaccharide

In principle, these substances in their structure and functions largely repeated previous class, but because it makes no sense to dwell on this in more detail.What are the chemical properties of carbohydrates, in this group?The most important members of the family are sucrose, maltose and lactose.All of them can be described by the formula S12N22O11 as are isomers, but this does not negate the huge differences in their structure.So what are typical complex carbohydrates, a list and description of which you can see below?

Sucrose

Its molecule is composed of two cycles at once, one of them is a six-membered ring (α-glucose residue), and the other - a five-membered (residual β-fructose).Connect all this construction by glycoside hydroxyl glucose.

Production and overall value

According to the preserved historical data, still three centuries before Christ sugarcane learned how to get in ancient India.Only in the mid-19th century, it turned out that a lot more of sucrose less for this effort can be extracted from sugar beets.In some varieties it contains up to 22% of the carbohydrate, while the reed content may be within 26%, but this is only possible under ideal growth conditions and favorable climate.

We have already said that carbohydrates are readily soluble in water.It is based on this principle to obtain sucrose, when used for this purpose devices diffuser.Possible to precipitate the impurities, the solution is filtered through a filter, which include lime.To remove from the obtained calcium hydroxide solution, is passed through a conventional carbon dioxide.The precipitate was filtered off, and the sugar syrup is evaporated in special furnaces to yield already familiar sugar.

Lactose

This carbohydrate is in an industrial environment stands out from regular milk, which contains in excess of fats and carbohydrates.It contains substances that quite a lot: for example, cow's milk contains about 4-5.5% lactose, and milk of women it comes to the volume fraction of 5,5-8,4%.

Each molecule of glycidol 3 consists of residues and a galactose-glucose pyranose form, which form a connection by the first and the fourth carbon atom.

Unlike other sugars, lactose y is one exclusive property.This is the complete absence of water absorption, so that even in a humid environment, this did not dampen the glycine.This property is widely used in the pharmaceutical industry: if a member of a drug in powder form part of the usual sucrose, it is necessary to add lactose.It is completely natural and harmless to the human body, unlike many artificial additives that prevent caking and wet.What are the functions and properties of carbohydrates of this type?

biological significance of lactose is extremely high, since lactose is the most important nutritional components of milk of all animals and humans.As for maltose, its properties are somewhat different.

Maltose

is an intermediate product which is obtained by the hydrolysis of starch.The name "maltose" was due to the fact that the formed largely under the influence of malt (malt in Latin - maltum).It is widely distributed not only in plant but in animals and organisms.In a large number of images in the digestive tract of ruminants.

Chemical structure and properties of this molecule

carbohydrate composed of two α-glucose units in the pyranose form, which are interconnected by the first and fourth carbon atoms.In view of a colorless, white crystals.The taste - sweetish, well soluble in water.

polysaccharides

It should be remembered that all polysaccharides can be viewed from the point of view that they are the products of condensation of monosaccharides.Their general chemical formula - (SbN10O5) n.In this article we will look at the starch as it is the most typical representative of the family.

Starch

formed by photosynthesis, large amounts deposited in the roots and seeds of plant organisms.What are the physical properties of the carbohydrates of this type?In appearance is a white powder with a poorly pronounced crystallinity, insoluble in cold water.The hot liquid forms a colloidal structure (paste, jelly).In the digestive tract of animals, there are many enzymes that contribute to its hydrolysis to form glucose.

are the most common natural polymer which is formed of a plurality of a-glucose residues.In nature, at the same time there are two forms: amylose and amshopektin.Amylose, being a linear polymer may be dissolved in water.The molecule consists of alpha-glucose residues which are linked through the first and the fourth carbon atom.

It must be remembered that this starch is first visible product of photosynthesis.In wheat and other cereals it contains up to 60-80% whereas in potato tubers - 15-20%.By the way speaking, mean starch grains under a microscope can accurately determine the species of plants, because they are different.

If carbohydrate rapidly heated, it is a huge molecule will decompose rapidly to form smaller polysaccharides which are known as dextrin.They starch one general chemical formula (S6N12O5) x, but there is a difference in the value of the variable "x" is smaller than "n" in the starch.

Finally a table which reflects not only the major classes of carbohydrates, but also their properties.

These are the functions and properties of the main classes of carbohydrates.