Carbohydrate

Carbohydrate

Carbohydrate are polyhedral alcohol having aldehyde s or Keaton groups or compounds which yields those
derivatives on hydrolysis.Here hydrated carbon is present.Example : Glucose, Fructose,Starch etc.

Classification

Classified  into four major groups according to the number of simple sugar unit present in the molecule
1.Monosaccharides ( simple sugar ) : Those carbohydrates which can not be hydrolysed fructose into a
simpler from they contain only one unit of simple sugar Example-Glucose, Fructose etc  
Trioses, tetroses, penoses, hexoses or heptoses according to the number of carbon atom present in the
molecule. Aldoses and ketoses, according to the nature of reducing ( aldehyde or ketone group ) they contain  
2.Disaccharides : Those which yield two molecules of same or different monosaccharides when hydrolysed.
Example : Sucrose ( Glucose+Fructose),Maltose (Glucose+Glucose), Lactose ( Glucose+Galactose ).
3.Oligosaccharides : Those which yield 3-10 monosaccharide unites on hydrolysis.Example : Rabinose,
Raffinose etc.
4.Polysaccharids : Those which yield an indefinetely larger number( more than 10 melecules ) of monosacchrides
on hydrolysis. Example : Starches, dextrins,glycogen etc.

Starch : It is the most important food source of carbohydrate and is found in cereals, potatoes, legumes and others. It is formed of a glucosidic chain.This produces only glucose on hydrolysis.So it is celled glucosan

Glycosides

Glycosides are compounds formed from a condensation between a monosaccharide, or monohaccharide residue and the hudroxy1 group of a second compound that may or may not ( incase of glycone ) be another monosac charide. Example : cardiac, glycoside.

Deoxy sugar : Are those in which a hydroxy1 group attached to the ring structure has been replaced by a
hydrogen atom.Example : Deoxyribose.

Amino sugar : Sugars containing an amino group are called amino sugars. Example :D-glucosamine,
D-Galactosamine, and D-mannosamine.
 
In Monosaccharide : Hexoses are the most importent class of monosaccharides. They are widely distributed in nature either free from or in combination with other molecules. Biologically importent hexoes are glucose fructose galactose and manose, among them glucose is most importent.

In polysaccharide : Glycogen is the most importent plysaccharide for the human being  because via the pathway of glycogenolysis it liberate glucose units for ready energy.

Properties of carbohydrate : They are colourless  crystaline compounds having a sweet taste.Chemically they are derivatives of polyhydric alcohols.The aldoses are derived from primary alcohol and ketoses from secondary alcohols.By virtue of alcoholgroup they easily from esters with acids.By virtue of the aldehyde or ketone groups, the simple sugars are powerful reducing agent. Due to the presence of asymmetric carbon atoms in the molecule, monosaccharides may remain in many ismeric forms.Simple sugars rotates in the plane of polarised light and therefore may exists in either dextro or levo forms.Simple sugara condense and form bigger carbohydrate molecules e.g polysaccharides. The monosaccharides may be reduced to their corresponding alcohols bu reducing agents such as sodium amalgam.Sugar not only remain as straight chain compounds but may also remain in the from of rings.

Function ( biomedical ) importance of carbohydrate :It also constitutes the structural material of the organism.Acts as importent storage of food material of the body.Actively concerned with protein and fat metabolism i.e protein and fat metabolized on the back ground of carbohydrate.It gives nutrition  to the nervous tissue and retina.It prevents ketosis.Carbohydrate is a protein sparer,that is carbohydrate is burned in preference to the burning of protein. Antibodies clotting factors and peptide hormones contain oligosaccharides.Diseases associated with carbohydeate are- diabetes mellitus, galactosaemia glycogen storage diseases and actose intolerance.Sugar solution is used as I.V fluid.Some drugs are chemically glycosides- are used as drug i.e cardiac glycosides streptomycin.    
 
Inversion of sucrose : Inversion of sucrose reffers to that phenomenon when the dextrorotatory property of sucrose solution changes into levorotatory from because of the hydrolysis of sugar into glucose and fructose.Sucrose is dextrorotatory but on hydrolysis it yields a crude mixture( Glucose+Fructose ) which is often called invert suger because the strongly levorotatory fructose inverts the previous dextrorotatory action of