Chapter 23 - Introduction

| Chapter 23 Tutorial Home

Screen 1 of 7

To fully appreciate this tutorial, you should be familiar with the concepts of:
• Characteristics of living cells
• Biologically important molecules
• Organization of the cell
• Cell structure

After this tutorial, you will be able to:
• Describe the structure of a virus and compare it with a free-living cell.
• Contrast viruses and bacteria.
• Describe the function of viral and bacterial structures.
• Explain the role of viral and bacterial structures in disease.

What makes viruses and bacteria different?

Tutorial Menu

Viruses
Bacteria
Summary

Have you ever heard someone use terms such as "bug" or "germ" to describe the causative agent of an illness? Many times, agents that we call "bugs" or "germs" are actually viruses or bacteria. There are many important differences between viruses and bacteria. The most important of these is that bacteria are cellular organisms, and viruses are not. Viruses lack many of the components found in cellular organisms. Additionally, viruses do not respond to stimuli, and they are not metabolically active like other cellular organisms. This tutorial will introduce you to viruses and bacteria and some of their important structures and their functions.