Question

Classify the following into monosaccharides, oligosaccharides and polysaccharides.
( 1 ) starch, ( 2 ) glucose, ( 3 ) stachyose, ( 4 ) maltose, ( 5 ) raffinose, ( 6 ) cellulose, ( 7 ) sucrose, ( 8 ) lactose.

Answer 1

Hint: An attempt to this question can be made by determining the meaning of the terms, monosaccharides, oligosaccharides and polysaccharides. The differentiating factor among these three is the number of carbon atoms present in the organic compound. So, write the condensed form the given compounds and sort them into the following categories and thus answer the question.


Complete step by step answer:
- In the question a set of compounds are given and we have to classify these compounds into monosaccharides, oligosaccharides and polysaccharides.
- We will define the terms monosaccharides, oligosaccharides and polysaccharides as suggested in the hint.
- Monosaccharides are commonly called simple sugars and are considered as the most basic units of carbohydrates. They are reducing in nature.
- Oligosaccharides are a class of carbohydrate formed by a minimum of 3 and a maximum of 10 simple sugars linked together.
- Polysaccharides are long chains of monosaccharide compounds or simple sugars that are linked by glycosidic bonds.
We will now classify the compounds.
-Starch is a complex sugar produced by plants. It is a polysaccharide.
-Glucose is a simple sugar. Thus, it is a monosaccharide.
-Stachyose is a tetrasaccharide. It belongs to the class oligosaccharide.
-Maltose is a disaccharide and belongs to oligosaccharide.
-Raffinose is a trisaccharide. It belongs to the class oligosaccharide.
-Cellulose is a complex sugar. It belongs to the class, polysaccharide.
-Sucrose is a disaccharide and belongs to oligosaccharide.
-Lactose is a disaccharide and belongs to oligosaccharide.
And hence we could tabulate the compounds and its classification as given below:

Compound name	Classification
Starch	polysaccharide
Glucose	monosaccharide
Stachyose	oligosaccharide
Maltose	oligosaccharide
Raffinose	oligosaccharide
Cellulose	polysaccharide
Sucrose	oligosaccharide
Lactose	oligosaccharide

Note: It is important to know that disaccharides are also included in the class of oligosaccharides. This is the reason why maltose, sucrose and lactose are included in the class of oligosaccharide.