Chapter 3, Problem 3TF

Summary Introduction

Introduction:

Cellular membrane, nucleus, and cytoplasm are the three major components of a cell. Cellular membrane which surrounds the entire cell is composed of phospholipids and proteins. Peripheral proteins are generally found on the membrane surface and are temporarily attached to one face of the plasma membrane. Membrane proteins that traverse the entire cell membrane alone can serve as a membrane channel. A membrane channel aids in the transfer of solutes from one side of the cell membrane which is selectively permeable to the other side of the membrane. Such integral proteins are called as transmembrane proteins. Hormones, like epinephrine (first messenger) do not have the ability to enter the cell through the cell membrane. Thus, they activate the production of a second messenger within the cell.