Question

Are glucose and fructose structural isomers?

Answer 1

Hint: Glucose and fructose are sugars and are classified as monosaccharides. These both contain six carbon atoms and have the same molecular formula, but the only difference is at the functional group. Glucose has an aldehyde functional group and fructose has a ketone functional group.

Complete answer:
Isomers are the compounds or molecules that are having the same molecular formula but differ in the structure or spatial arrangement.
Structural isomers are classified into functional isomers, positional isomers, chain isomers, metamers and tautomers.
Stereo isomers are classified into configurational and conformational isomers. The configurational isomers are again classified into geometrical and optical isomers.
Glucose is an aldohexose consisting of six carbon atoms. The molecular formula of glucose is \[{C_6}{H_{12}}{O_6}\], the functional group present in glucose is aldehyde.
Fructose is a ketohexose consisting of six carbon atoms. The molecular formula of glucose is \[{C_6}{H_{12}}{O_6}\], the functional group present in glucose is ketone.
Both glucose and fructose are sugars.
The structure of glucose is \[OHC - {\left( {CHOH} \right)_4} - C{H_2}OH\]
The structure of fructose is: \[HOC{H_2} - CO - {\left( {CHOH} \right)_3} - C{H_2}OH\]
Thus, by looking at the above structures of glucose and fructose, both are having the same molecular formula but there is a difference in the functional groups. Thus, these are functional isomers and come under the structural isomers.

Note:
The functional isomers, positional isomers, chain isomers, metamers and tautomers come under structural isomers, as glucose and fructose are having aldehyde and ketone functional groups with the same molecular formula these come under structural isomers.