marți, 9 aprilie 2013

Monosaccharides and polysaccharides

Monosaccharides and polysaccharides
          Are common in both vegetable and in the animal, having a great biological importance. The simplest monosaccharide is glycolic aldehyde, which is a aldodioza. Tetrozele not found in nature. Pentoses are widespread in nature: arabinose, xylose, ribose, and hexoses: glucose, galactose, fructose, sorboza.Dintre plant polysaccharides starch and cellulose mentions, and of the animal glycogen stated.
ABOUT monosaccharides

           Monosaccharides are hydroxy-carbonyl compounds that contain in their molecule, in addition to the hydroxyl group-OH, an aldehyde group (Aldose) or ketones (ketosis).Depending on the number of carbon atoms that make up molecules, monosaccharides are classified dioze (2 carbon atoms), trioze (to 3 carbon atoms), tetroze (4 atoms), pentoses (5 atoms), and hexose.The simplest monosaccharide is glycolic aldehyde, which is a aldodioza. Tetrozele not found in nature. Pentoses are widespread in nature: arabinose, xylose, ribose, and hexoses: glucose, galactose, fructose, sorbose.  Pentose - aldo-pentose Of the eight, only four are found in nature, and the keto-pentose, only two. Pentoses is characterized by the formation of furfural on heating with dilute mineral acids.   Xylose - is widespread in nature, as a component of plant gums and form of xylan, a polysaccharide accompanying wood pulp and is part of the so-called heiceluloza. Xylan is also found in various lignified materials as straw, corn cobs, husks, cotton and sunflower.For these materials, for example. From corn stalks, yielding xylose by dilute acid hydrolysis, the resulting solution removes glucose fermentation and xylose concentration crystallizes. Xylose, like other pentose, is not fermented by yeast usual but Monilia and Torula varieties grow well in solutions resulting from the hydrolysis of straw and stalks of reed.    Arabinose - is widespread in plants, which takes the form of a polysaccharide called araban, and as a component of plant gums and mucilages and also hemicelulozei.De was found in glycosides and disaccharides. Obtained by hydrolysis of cherry gum or beet after the sugar extraction.   Ribose - a compound greatest biological importance because it Along with deoxy-ribose, a critical component aacizilor nucleus and appears in every living cell. In nucleic acids, D-ribose is contained in the form furanozica linked glycoside of some pyrimidine and purine derivatives and phosphoric acid. Is obtained from nucleic acids by hydrolysis with dilute acid.    Hexose - Main class representatives are glucose, mannose, galactose, fructose, which are also the most common monosaccharides. They are found free in nature in the form of glycosides, oligosaccharides and polysaccharides. The four natural monosaccharides by yeast ferments the beer.    Mannose - not dating free in nature. Instead, they are common polysaccharides, mananii. One of them, ivory vegetable ivory nut, the fruit of a South American palm is the best material for getting mannose, acid hydrolysis, the resulting syrup, mannose crystallizes not only difficult, usually only after sowing. Mannose is converted by reduction in mannitol and form of this hexitol by oxidation. Mannose oxidation leads to acid and acid Manon manozaharic.    Galactose - not found rarely free, but is often found in disaccharides, trisaccharides, polysaccharides. Also found in glycosides and brain phosphatides. Galactose is obtained by the hydrolysis of lactose with glucose. Transform mammary gland tissue in vitro glucose galactose.Galactose is crystallized form piranozica.Prin sodium amalgam reduction or aluminum, galactose switch in optical hexahidroxilic inactive alcohol, dulcitol, a substance that is found in nature, in plants. Galactonic acid oxidation forms, monocarboxylic and mucic acid, dicarboxylic optical inactive.Galactose is one of the few sugars L Series polysaccharide found in nature as in mucilage of flax seed in galactogenul the snail and other algal polysaccharides isolated from their hydrolysis marine.Prin form, in most cases, galactose, which removes fermentation with yeast, the only challenged by it.

Chromatographic        Typical chromatographic method discovered by Russian botanist M. TVET (1906), using columns of particulate absorbent (activated carbon, aluminum oxide and so on in glass tubes) through which flows slowly separating substances whose solution follows. Different substances absorb in different regions of the spine. These regions may be even more distant by washing the column with another solvent. Desorb substances are then successively ...


Polysaccharides are obtained by eliminating a,, n "water molecules between multiple molecules of monosaccharides.- Is a mixture of two polysaccharides: amylose and amylopectin- Macromolecular structure- C6 H12 O6 → [C6 H10 O5] n- Industrial starch is made from potatoes or wheat flour- Appears as a fine, white, more or less bright- In industry, acid hydrolysis of starch is used in sugar processing and enzymatic hydrolysis to obtain ethanol
Cellulose - [C6 H10 O5] n- Is in the form of macromolecules filiform- 6 n 5 n CO2 + H20 → [C6 H10 O5] n n + 6 O2- Fresh pure cellulose obtained from cotton fibers- Cellulose is a white substance, fibrous macromolecular structure, tasteless and odorless, insoluble in water, dilute mineral acids and in organic solvents- The study of esterification led to the conclusion that each group C6 H10 O5 are contained three hydroxyl groups, on this basis, the molecular formula of cellulose can be written as:
Glycogen - [C6 H10 O5]it is called animal starch''is found in all cellsis a white powder, soluble in water but insoluble in alcoholby acid hydrolysis, splits glycogen into glucose