Loading....
Coupon Accepted Successfully!

Introduction to Carbohydrates

Definition

Carbohydrates are poly hydroxy aldehydes or ketones or their derivatives can also be defined as aldehyde / ketone derivatives of higher polyhydric alcohols.

Classification of Carbohydrates 

  1. Monosaccharides (CnH2nOn) : are simple form of carbohydrates which cannot be further hydrolyzed. Subdivided further based on (i) no. of carbon atoms (ii) aldehyde/ketone group present. 

General Formula

Aldosugar                      

Ketosugar

Trioses

Glyceraldehyde

Dihydroxyacetone

Tetrose

Erythrose

Erythrulose

Pentoses

Ribose

Ribulose

Hexoses

Glucose

Fructose

 

Glyceraldehyde is smallest carbohydrate of Aldose family and Dihydroxyacetone is smallest carbohydrate of ketose family.

  1. Disaccharides Cn(H2O)n-1 : yield two molecules of same/different monosaccharide on hydrolysis Cn(H2O)n-1

 

 

Both Sucrose and Trehalose are NON REDUCING sugars.

  1. Oligosaccharides: yield 2-10 molecules of monosaccharides units on hydrolysis.
  2. Polysaccharides (C6H10O5) : yield more than ten molecules of monosaccharides on hydrolysis
  3. Homopolysaccharides (Homo glycans) : Polymers of same monosaccharides unit. e.g. Starch, Glycogen, Inulin, Cellulose, Dextrin, Dextran, Agar. Of these starch, glycogen cellulose Dextrin and dextran are homopolymers of glucose, while Inulin is homopolymer of fructose and agar of galactose.
    1. STARCH – starch is plant homopolymer of gulose it is mixture of amylose & amylopectin. amylose is liner linked by α 1 - 4 bonds. Amylopectin is branched and has α1 - 6 linkages in addition of α1 - 4 linkage between glucose residues.
    2. Glycogen is animal starch. structurally it resembles amylopectin but is more extensively branched as α1 6 linkages occur after every 10-18 units whereas in amylopectin they occurs about every 25 residues. Glycogen is stored in hepatocytes & muscle cells.
    3. Cellulose’s – cellulose is chain of glucose residues linked by β 1- 4 glycosidic bonds, ruminant can   
    4. digest cellulose because of presence of bacteria in their stomach which hydrolyze β1-4 glycosidic bonds.  
  4. Heteropolysaccharides: Polymers of different monosaccharide units or their derivatives e.g. mucopolysaccharides (glycosaminoglycans)The glycosaminoglycans (GAGs) are made up of repeating disaccharides containing a uronic acid (Glucuronic or iduronic) or hexose (galactose) and a hexosamine (galactosamine or glucosamine). Sulfate is also frequently present.  

Hyaluronic acid

Heparan sulphate

 

Heparin   

Dermatan sulphate

Keratan sulphate

 

Asymmetric carbon atom : A carbon atom to which has same molecular formula but have different structure are known as steroid isomer atoms or group of atoms are attached.

    I. ISOMERISM

Please Register
Create Account
This course is powered by:-
Test Your Skills Now!
Take a Quiz now
Reviewer Name