Chapter 23, Problem 61A

Interpretation Introduction

Interpretation:

The reason should be determined for the following statement along with an equation.

Disaccharides and polysaccharides can't be broken down in the absence of water.

Concept introduction:

A biological molecule which consists of carbon, hydrogen and oxygen is known as saccharide or carbohydrate. The general formula of saccharide is ${{\text{(CH}}_{\text{2}}\text{O)}}_{\text{n}}$.

Saccharides (sugar) are classified as: monosaccharides, disaccharides and polysaccharides.

Monosaccharides are defined as a simpler carbohydrate which contains one sugar molecule and can’t ne hydrolysed into smaller carbohydrate.

Disaccharides are defined as a saccharide which contains two sugar molecules that is when two monosaccharides are linked by glycosidic bonds. It is a double ring structure.

Polysaccharides are defined as a saccharide which contains many units of sugar molecules that is more than two monosaccharides are linked by glycosidic bonds.

Explanation of Solution

Disaccharides are made up of two monosaccharide units. When two monosaccharides react or combined with each other, results in the formation of a disaccharide with the removal of water and the bond formed between them is ether or glycosidic bond. The reaction is known as condensation reaction.

Now, in the reverse process, a disaccharide digested to form two monosaccharides in the presence of water with the breaking of ether bond at same time. The reaction is known as hydrolysis reaction.

For an example:

The hydrolysis of sucrose results in the formation of glucose and fructose.

Thus, addition of water molecule is necessary to break the ether bond or glycosidic bond present between the disaccharide.