Carbohydrates, or saccharides, are one of the main groups of organic compounds. They are part of the cells of all living organisms.
The main function of carbohydrates is energy (during the breakdown and oxidation of carbohydrate molecules, energy is released, which ensures the vital activity of the body). With an excess of carbohydrates, they accumulate in the cell as reserve substances (starch, glycogen) and, if necessary, are used by the body as an energy source. Carbohydrates are also used as a building material.
General Carbohydrate Formula:
Cn (H2O) m.
Carbohydrates are made up of carbon, hydrogen and oxygen.
Other elements can also be included in carbohydrate derivatives.
Water soluble carbohydrates. Monosaccharides and disaccharides
Of the monosaccharides, ribose, deoxyribose, glucose, fructose, galactose are of the greatest importance for living organisms.
Glucose is the main source of energy for cellular respiration.
Fructose is an integral part of the nectar of flowers and fruit juices.
Ribose and deoxyribose are structural elements of nucleotides, which are monomers of nucleic acids (RNA and DNA).
Disaccharides are formed by combining two molecules of monosaccharides and are similar in properties to monosaccharides. For example, both are highly water soluble and have a sweet taste.
sucrose (cane sugar), maltose (malt sugar), lactose (milk sugar) – disaccharides formed as a result of the fusion of two monosaccharide molecules:
sucrose (glucose + fructose) is the main product of photosynthesis transported in plants.
Lactose (glucose + galactose) is a part of mammalian milk.
Maltose (glucose + glucose) is a source of energy in germinating seeds.
Functions of soluble carbohydrates: transport, protective, signaling, energy.
Water insoluble polysaccharides
Polysaccharides are composed of a large number of monosaccharides. With an increase in the amount of monomers, the solubility of polysaccharides decreases and the sweet taste disappears.
Example: polymeric carbohydrates: starch, glycogen, cellulose, chitin.
Functions of polymeric carbohydrates: structural, storage, energetic, protective.
Starch consists of branched spiralized molecules that form storage substances in plant tissues.
Cellulose is an important structural component of the cell walls of fungi and plants.
Cellulose is insoluble in water and has high strength.
Chitin consists of amino derivatives of glucose, is part of the cell walls of some fungi and forms the outer skeleton of arthropods.
Glycogen is a reserve carbohydrate of an animal cell.
Complex polysaccharides are part of the connective tissues of animals. They are found in the intercellular substance of the skin, in cartilage and tendons.