Chapter 7, Problem 17A

Summary Introduction

To explain:

The term fluid mosaic model is used to describe the plasma membrane.

Introduction:

The cell is a dynamic unit and carries out varies biological processes. The different components of the cell are specifically designed to execute different functions. The plasma membrane of the cell is selectively permeable in nature.

Explanation of Solution

A mosaic may be defined as consistent pattern or arrangement of molecules or cells which each of the components of the element is built up of smaller irregular or regular pieces. The various components of plasma membrane including phospholipid, cholesterol, proteins and carbohydrates, are arranged in a way that it gives a patterned arrangement which is known as fluid mosaic model. The cell membrane is made up of many proteins and other substances has a fluid matrix. The phospholipid present in the cell membrane forms a lipid bilayer which allows the protein molecules are embedded in it. The membrane is selectively permeable as it allows passage of specific molecules and ions. The lipid bilayer makes the plasma membrane elastic in nature.

Each lipid molecule contains water repelling tail and a water attracting head. The water repelling face the interior of the bilayer while a water attracting head region is held together by intermolecular forces.

Conclusion

The different components of the plasma membrane like proteins, lipids are loosely attached against a fluid matrix, hence, it is also described as fluid mosaic arrangement of plasma membrane.