What is the basic structural difference between glucose and fructose?

OR

Write the products obtained after hydrolysis of lactose.

Sucrose on breaking gives two molecules with same molecular formula but different structures: Glucose and fructose, where are both monosaccharide sugars.

Glucose is an aldehyde and whereas fructose is a ketone and has following structure according to Fischer projections.

Another difference is the number of chiral carbons in glucose is 4 whereas in fructose is 3. Also the number of 2° alcohol is 4 for glucose and 3 for fructose.

OR

Write the products obtained after hydrolysis of lactose.

Hydrolysis of lactose gives mixture of two compounds D-galactose and D-glucose. The reaction is as follows:

NOTE: the cyclic structures shown by Haworth projection are given as follows: