Chapter 5.1, Problem 1CYL

Summary Introduction

To describe:

The components, structure, and function of the cell membrane; how the different components of cell membrane contribute to their function; and the fluid mosaic model of cell membranes.

Introduction:

There is a basic structure which is common to all types of cell membranes- double phospholipid layer, with proteins dangled in between. The main role of the phospholipid layer is to separate the cell contents from the interstitial fluid, and also the organelles from the fluid present inside the cells. On the other hand, proteins mainly optimize the biochemical processes, and help in the interaction between adjacent cells; and they also help in the essential selective exchange of nutrients.

This type of structure of the cell membrane is termed as a fluid mosaic model by S. J Singer and G. L. Nicolson. To remain functional, cell membranes have to remain fluid. This fluidity increases with an increase in temperature due to increased vibrations of molecules whereas, in cooler temperature, the fluidity of the cell membrane decreases.

The change in membrane fluidity is stabilized by the presence of cholesterol in the plasma membranes, which decreases fluidity in higher temperatures and increases it at lower temperatures.

Various proteins that are suspended in the phospholipid layers form a mosaic structure. These proteins constitute five different categories- enzymes, connection proteins, recognition proteins, receptor proteins, and transport proteins.

Summary Introduction

To determine:

How the different components of cell membrane contribute to their function

Introduction:

The basic structure which is common to all types of cell membranes is a double phospholipids layer, with proteins dangled in between. To remain functional, cell membranes have to remain fluid. Various proteins that are suspended in the phospholipid layers form a mosaic structure. These proteins constitute five different categories- enzymes, connection proteins, recognition proteins, receptor proteins, and transport proteins.

Summary Introduction

To describe:

The fluid mosaic model of cell membranes.

Introduction:

A fluid mosaic model comprises a fluid which is formed by the two layers of phospholipids, and a mosaic of different types of proteins amidst the phospholipids bilayer.