ASSIGNMENT

Assignment

Assignment

1)

Carbohydrates are the historic name of a group of natural compounds, capable of being described by the formula elementary CH 2 O, suggesting that they are composed mostly of carbon and water - hence the name. Subsequent studies showed that the elemental formula CH 2 O corresponds to the molecular formulas (CH 2 O) n and is the least important common feature of compounds of this group. Carbohydrates are one of the most important elements of living nature. Formed from water and carbon dioxide in the leaves of a catalyst comprising the reaction (chlorophyll) under the action of electromagnetic radiation energy (light) in the process of photosynthesis.

Most vegetable hydrocarbons are starch and cellulose (polysaccharides) and sugars (glucose, fructose, mannose, galactose) and disaccharide - sucrose (sugar food). Along with the plant organisms get into the animal, where it is hydrolyzed to sugars and partially combusted to CO 2 and H 2 O, releasing energy at the same time, taken earlier in the process of photosynthesis.

Excess sugars are combined in the liver in animal reserve sugar - glycogen, which is a source of stored energy for the body. In addition, biochemical changes in glucose produce fats, proteins and partly by the formation of amino acids in the reaction with nitrogen-containing compounds. So carbohydrates in its various forms are both material energy ("fuel" for the body) and are involved in the development of building material, which is a protein.

The basic sugar molecules, so-called sugars are monosaccharides or (C2). The presence of an aldehyde group causes are easily oxidizing compounds (strong reducing agents), which give characteristic reactions with reagents Tollens and Fehling. Behave identically with a group of keto sugars because oxidation reactions are also characteristic for a-hydroxyketones. Distinguish ketosis (keto group of sugars) of aldoses (sugars with aldehyde group) may be a reaction with bromine water.

Chemistry of sugars is not the easiest, since sugars are compounds of complex nature. Simple sugars, also sometimes called monocukrami, the compounds of polyhydric alcohols which are aldehyde ( aldose ) or ketone ( ketose ). Already in the participation of several different functional groups per molecule lies many complexities sugar chemistry. The functional groups contained in the molecule monocukru cause the molecule may react with a second molecule of sugar - different or the same, to form disaccharides, and oligosaccharides and polysaccharides.

It can also react with itself to form an aldehyde group by reaction with alcohol, cyclic structures. Another complicating factor chemistry of sugars, is the presence in the molecule monocukru asymmetric carbons and the associated relatively large amount of optical isomers (2 n where n - the number of asymmetric carbons in the molecule). Asymmetric carbons are all carbon atoms in the chain, except the stress (and also, of course, but Ketosis C2).

The basic structure of the sugar molecules - it means there aldohexose 2 4 = 16 of optical isomers, that is, 8 pairs of enantiomers. In addition, for example, glucose, to form a ring structure of the internal hemiacetal (reaction of ...