Question

Name the functional group common to both glucose and fructose.

Answer 1

Hint: Glucose is a subcategory of carbohydrates. It is mainly made by plants during photosynthesis from water and carbon dioxide using sunlight. Fructose is a natural sugar present in fruits, vegetables etc. Fructose reacts with glucose to form sucrose. These both have similar chemical formulas; only difference is in their functional groups.

Complete step by step solution:
We are given to name the common functional group present in glucose and fructose.
Glucose is also called dextrose, is one of a group of carbohydrates known as simple sugars. Glucose is produced by the reaction of carbon dioxide with water in the presence of sunlight releasing oxygen.
$6C{O_2} + 6{H_2}O\xrightarrow{{sunlight}}{C_6}{H_{12}}{O_6} + 6{O_2}$
It is generated in plants and our body uses it for energy. Its chemical formula is ${C_6}{H_{12}}{O_6}$
Fructose is also a sugar found in fruits, vegetables, honey etc. It is often bonded to glucose to form sucrose. Its chemical formula is also ${C_6}{H_{12}}{O_6}$.
Every cell in the human body can use glucose, but only the liver can metabolize fructose in huge amounts.
Structure of Glucose is $OH - \mathop {\mathop C\limits_|^| }\limits_H^H - \mathop {\mathop C\limits_|^| }\limits_{OH}^H - \mathop {\mathop C\limits_|^| }\limits_{OH}^H - \mathop {\mathop C\limits_|^| }\limits_H^{OH} - \mathop {\mathop C\limits_|^| }\limits_{OH}^H - \mathop {\mathop C\limits^| }\limits^H = O$
Structure of Fructose is $OH - \mathop {\mathop C\limits_|^| }\limits_H^H - \mathop {\mathop C\limits_|^| }\limits_{OH}^H - \mathop {\mathop C\limits_|^| }\limits_{OH}^H - \mathop {\mathop C\limits_|^| }\limits_H^{OH} - \mathop {\mathop C\limits_{||} }\limits_O - \mathop {\mathop C\limits_|^| }\limits_H^H - OH$
In glucose we have five alcohol groups ($ - OH$) and one aldehyde group ($R - \mathop {\mathop C\limits^| }\limits^H = O$).
In fructose also we have five alcohol groups but one ketone group ($R - \mathop {\mathop C\limits^| }\limits^R = O$), where R group is a chain of carbon atoms or one carbon atom.

Therefore, the common functional group in Glucose and Fructose is alcohol group, $ - OH$.

Note:
Do not confuse between an aldehyde and a ketone. Aldehyde and ketone both incorporate a carbonyl functional group ($C = O$). Aldehyde is a type of ketone where one R-group of ketone is replaced with a hydrogen atom. Presence of a hydrogen atom attached to carbon-oxygen double bond is seen in aldehyde whereas it is not seen in a ketone.