Chapter 13, Problem 13.1EP

Where does carbohydrate digestion begin in the body, and what is the name of the enzyme involved in this initial digestive process?

Interpretation Introduction

Interpretation: To identify the beginning site of digestion of carbohydrates in the body and the name of the enzyme involved in the initial digestive process.

Concept introduction: Carbohydrates are the biomolecules composed of carbon, oxygen and hydrogen atoms. Carbohydrate molecules are joined together by the glycosidic linkage.

Carbohydrates are classified as monosaccharide, disaccharide, oligosaccharide, and polysaccharide. Monosaccharides are the simplest carbohydrate units that cannot be hydrolyzed further to give the smallest units. Disaccharides contain two monosaccharide units and on hydrolysis, it gives two monosaccharide molecules. Oligosaccharides contain 3 to 10 monosaccharide units. Polysaccharides contain many carbohydrate units that vary from 100 to 50,000 monosaccharide units. Starch and glycogen are examples of polysaccharides.

Saliva is a fluid secreted by the salivary glands. It contains 99% water, organic molecules, and a small amount of inorganic ions. $\text{Salivary }\alpha -\text{amylase}$ is a constituent of saliva.

Answer to Problem 13.1EP

The digestion of carbohydrates begins in the mouth. $\text{Salivary }\alpha -\text{amylase}$ enzymes are involved in the initial digestive process.

Explanation of Solution

The $\text{salivary }\alpha -\text{amylase}$ enzymes are present in the mouth that catalyzes the hydrolysis of $\alpha -\text{glycosidic}$ linkages present in the carbohydrate molecules. The larger carbohydrates molecules are converted to smaller polysaccharide molecules and maltose, a disaccharide. Food is swallowed very quickly, therefore, a small amount of digestion of carbohydrates begins in the mouth.

Conclusion

The $\text{salivary }\alpha -\text{amylase}$ enzymes present in the mouth break the glycosidic linkages between the carbohydrates molecules and convert some polysaccharide chains to smaller polysaccharide and disaccharide chains. Therefore, a small amount of digestion of carbohydrates begins in the mouth by $\text{salivary }\alpha -\text{amylase}$ enzymes.