Purines

Pyrmidines

(1) Its molecules is double ringed.

(2) It is a nine membered ring.

(3) Its molecule is larger.

(5) For eg. Adenine and guanine.

(1) Its molecule is single ringed.

(2) It is six membered ring.

(3) lIts molecule is smaller.

(4) For e.g Thymine and cytosine. 

Reducing Sugars

Non-reducing sugars

(1) Give bright red-precipitate with Fehling’s or Benedict’s solutions.


(2) Have free aldehyde or ketone group which reduces Cu⁺⁺ to Cu⁺.

(3) Cannot be hydrolysed.

(4) All monosaccharides and some disaccharides like maltose and lactose are reducing sugars.

(1) Do not give bright red-precipitate with Fehling’s or Benedict’s solutions.

(2) Do not have free aldehyde or ketone group to reduce Cu⁺⁺ to Cu⁺.

(3) On hydrolysis give rise to reducing sugars.

(4) Sucrose is non-reducing sugar.

Oils

Fats

(1) Rich in unsaturated fatty acids.

(2) Liquid at ordinary temperature.

(3) Contain essential fatty acids.

(1) Rich in saturated fatty acids.

 (2) Solid or semi-solid at ordinary temperature.

(3)Do not contain essential fatty acids.

Aldose sugar

Ketose Sugar

(1) It has an aldehyde group.

(2) First carbon forms a part of aldehyde group.

(3) Aldoses are more common in nature e.g. ribose, glucose.

(1) It has a ketone group.

(2) Second carbon forms a part of keto group.

(3) Ketose are less common in nature, e.g. ribulose, fructose.

Pyranose ring

Furanose ring

(1) It is hexagonal.

(2) It has five carbon atoms in the ring and one oxygen atom. e.g. glucose, galactose.

(1) It is pentagonal.

(2) It has four carbon atoms and one oxygen atom in the ring. e.g. fructose.