Question

Which of the following is a pentose sugar?
a.) Glucose
b.) Fructose
c.) Ribose
d.) Cellulose

Answer 1

Hint: We should know that Pentose sugar is a monosaccharide with 5 carbon atoms. So, while classifying the options into pentose sugar, we need to compare their structures with the basic structure of pentose sugar.

Step by step answer: The pentose sugar as we know contains 5 carbon atoms. The two main functional groups attached to the sugar are often named in reference to the carbon to which they are bound.

The basic structures of the following options are:

Glucose:
 

From the structure we can see that there are 6 carbon atoms, and 5 hydroxyl groups. So the structure does not satisfy the basic criteria for pentose sugar. So this is not pentose sugar. Fructose:

                    

From the structure we can see that there are 6 carbon atoms. So the structure do not satisfy the basic criteria for pentose sugar. So this is not pentose sugar. Ribose:

                                   

From the structure we can see that there are 5 carbon atoms. So the structure resembles the structure of pentose sugar. So this is a pentose sugar.

Cellulose:

Cellulose is a polysaccharide. Therefore it cannot be a pentose sugar.

Therefore Ribose is the pentose sugar. Option C is the correct answer.

Note: We should have an idea that Ribose is produced in our body. It is used as medicine.
Ribose is used to improve athletic performance and the ability to exercise by boosting muscle energy. It has also been used to improve the symptoms of chronic fatigue syndrome and coronary artery disease.