Chapter U6, Problem 7STP

Interpretation Introduction

Interpretation:

The correct statement for the bonding of sucrose, maltose and lactose with receptor to describe the sweetness of them needs to be determined.

Concept introduction:

Carbohydrates are one of the most important biomolecules in living organism. They are polymers of certain monomer units which are known as monosaccharides. Monosaccharides are polyhydroxy carbonyl compounds.

These monosaccharides are bonded together to form disaccharides and polysaccharides. Lactose and maltose are disaccharides as they are composed of two monosaccharides, whereas sucrose is a polysaccharide.

Answer to Problem 7STP

Option (A) is correct answer.

Explanation of Solution

Reason for correct option: According to given figure, Lactose has least sweetness and sucrose is sweetest.

Out of 10 molecules, only 1 molecule of Lactose is bonded with receptor whereas 6 molecules of sucrose are bonded to receptors. It proves that sucrose molecules have strong intermolecular attractions with receptors and Lactose molecules have weakest intermolecular attraction. Thus, option (A) is correct answer.

Conclusion

Reasons for incorrect options: Sucrose molecules have strongest intermolecular attraction with receptors than maltose and lactose molecules. Thus, less sucrose molecules remain in saliva than maltose and lactose. Although out of 10, 6 molecules bind with receptor therefore it will not bind with all receptor sites.

It makes option (B), (C) and (D) incorrect answer.