Chapter 7, Problem 45A

Summary Introduction

To infer:

The reason for tapering off of the rate of diffusion with higher amount of glucose.

Introduction:

The movement of molecules from an area of higher concentration to lower concentration area is termed as diffusion. Diffusion is mainly seen in liquid and gaseous particles, as these particles can move easily. By this process, many molecules move in and out of living cells.

Explanation of Solution

Glucose is transported across the membrane via carrier protein. This is because, glucose is polar molecule and membrane is made of non-polar phospholipids. So, alone glucose cannot cross the cell membrane, it needs a medium to cross the membrane. The reason for tapering off rate of diffusion with increasing glucose concentration is that glucose concentration gets increased rapidly, but the availability of carrier proteins is too less. Due to which, after a certain level glucose molecules cannot cross the cell membrane, as there are no more carrier proteins available.