Carbohydrates. Their classification

Carbohydrates. Their classification.
Carbohydrates are very common in nature. These compounds consist of carbon, hydrogen and oxygen. Their composition is represented by the general formula Cn(H2O)m. Some representatives of carbohydrates, xylose C5H10O5, glucose C6H12O6, sucrose C12H22O11 and starch (C6H10O5), follow the general formula above, but the composition of some of them (methylpentoses C6H12O5, methylhexoses C7H14O6 deoxy sugars) differs. Complex carbohydrates (cellulose - kletchatka) give resistance and hardness to the plant, they are used for clothing (cotton), building materials and food (starch, sucrose) for humans.
Classification of carbohydrates
Carbohydrates are the largest class of organic compounds and are divided into two groups based on whether they are hydrolyzed, unhydrolyzed, and broken down into smaller molecules when hydrolyzed:
1. Simple carbohydrates or monosaccharides (mannoses);
2. Complex carbohydrates. These, in turn, are divided into sugar-like small-molecule polysaccharides (oligosaccharides) and high-molecular polysaccharides that are not sugar-like.
Carbohydrates (sugars, glycides) are a group of common organic compounds that, along with proteins and fats, are necessary for human, animal and plant life. It is one of the sources of energy produced as a result of metabolism in the body. According to its properties, it is close to oxyaldehydes and oxyketones. The general formula of the bulk of carbohydrates is CnH2nOn or Cn(H2O)m, examples of which are glucose (fructose) C6H12O6 from monosaccharides or sucrose C12H22O11 from disaccharides. About 80% of the mass of solid matter of plants, about 2% of the dry mass of animals corresponds to U. Plants synthesize carbohydrates from water with inorganic substances - carbon dioxide (SO2).
In a living organism, carbohydrates play the role of a source of energy in biological processes, raw materials for the synthesis of other intermediate or final metabolites for the organism. Carbohydrates include compounds containing nitrogen, sulfur, or phosphorus in addition to carbon, hydrogen, and oxygen.
Carbohydrates are divided into 2 large groups: monosaccharides and polysaccharides. Polysaccharides consist of sugar (oligopolysaccharides) - disaccharides (bioses), trisaccharides, tetrasaccharides and non-sugar polysaccharides. They are also called simple carbohydrates (monosaccharides or monosose) and complex carbohydrates (polysaccharides or polyoses).
2. Monosaccharides, their representatives, production, properties.
Mono and oligosaccharides — mol. substances that are well soluble in water with a low mass. Mol of non-sugary carbohydrates. mass is high, solutions exist only in colloidal form. Non-sugar carbohydrates (starch, cellulose) are composed of a large number of monoose molecules.
The structure of monoses is anicized using a series of reactions, it is taken into account that glucose forms 2-iodohexane when reduced with hydrogen iodide HI, glucose becomes gluconic acid when oxidized under mild conditions, and 5 hydroxyl groups are present when acylated and alkylated. Fructose has a ketone group instead of an aldehyde group in glucose. Monosaccharides, which refer to simple carbohydrates, are optically active crystalline substances that dissolve well in water, and most of them are sweet. has a repulsive property. Polyhydric aldehydes and ketone alcohols (often in the intracyclic hemiacetal form) are considered. These oligosaccharides consist of 2-10 monosaccharides linked by a glycosidic bond. Sucrose, trehalose, lactose, which are part of disaccharides, are common in nature. A large number of oligosaccharide glycosides (physiologically active substances) are used in medicine.
Monosaccharides can be considered as oxidation products of aliphatic polyols. Because these substances contain aldehyde or ketone groups as well as hydroxyl groups. But monosaccharides do not undergo hydrolysis. The name of monosaccharides is formed by reading the number of carbon atoms in their molecule by adding the suffix "oza" to the Latin name. For example,
C3H6O3—triose;
C4H8O4—tetrose;
C5H10O5—pentose;
C6H12O6—hexose;
C7H14O7—heptose, etc.
Monosaccharides with an aldehyde group are called aldoses, and those with a ketone group are called ketoses.
Pentoses and hexoses are mainly found in nature.