Ch 9: Understanding Viruses

About This Chapter

This comprehensive science chapter helps you better understand the basics of viruses. Inside, you'll find engaging lessons and mini quizzes that can be used for test preparation, homework help, independent learning and tutoring.

Understanding Viruses - Chapter Summary

In this chapter, you'll explore the fundamentals of viruses. As you work through these bite-sized and entertaining lessons, you'll see how viruses live, attack, replicate, mutate and affect host cells. You'll also compare different types of viruses. You can complete the chapter at your own pace using any Internet-connected device. To help you retain your knowledge, we've included lesson quizzes and a chapter exam. You can also print lesson transcripts and submit questions to our instructors if you have any. When you're finished, you'll be able to:

  • Understand virus structures and functions
  • Compare virus shapes
  • Summarize the overall life cycle of a virus
  • Interpret virus classification in terms of the viral genome and replication scheme
  • Compare DNA and RNA virus replication
  • Explain virus mutation
  • Differentiate between the bacteriophage lytic and lysogenic circles
  • Assess virus isolation, detection and identification
  • Evaluate concepts pertaining to immune system evasion, flu viruses and HIV
  • Describe the effect that viruses can have on host cells

10 Lessons in Chapter 9: Understanding Viruses
Test your knowledge with a 30-question chapter practice test
What Are Viruses? - Definition, Structure & Function

1. What Are Viruses? - Definition, Structure & Function

In this lesson, you'll learn some historical facts about viruses and the material they are composed of. Find out more as we review the capsid, nucleic acids, the viral envelope, viruses, virions, bacteriophages and virology.

Shapes of a Virus: Helical, Icosahedral, Prolate, Complex & Enveloped

2. Shapes of a Virus: Helical, Icosahedral, Prolate, Complex & Enveloped

Learn about the different shapes viruses can have, such as helical, icosahedral, prolate, complex and enveloped. Find out why one shape is particularly useful from an energetic standpoint.

The Life Cycle of a Virus: How Viruses Live, Attack & Replicate

3. The Life Cycle of a Virus: How Viruses Live, Attack & Replicate

Find out how viruses infect and replicate as we explore the important steps of the virus life cycle, including attachment, uncoating, penetration, replication, and release, as well as the lysogenic and lytic cycles.

Classification of Viruses: Viral Genome and Replication Scheme

4. Classification of Viruses: Viral Genome and Replication Scheme

Find out how viruses are classified based on their being double-stranded, single-stranded, positive-sense, negative-sense, or by having something called reverse transcriptase.

Replication of DNA Viruses

5. Replication of DNA Viruses

This lesson will give you a basic overview of how DNA viruses replicate inside of a host cell. We will cover the entry, integration, replication and release of DNA viruses.

Replication of RNA Viruses

6. Replication of RNA Viruses

This lesson will give you a basic overview of how different types of RNA viruses replicate inside of an animal cell. We will cover the essence of being double-stranded and retroviruses, as well as positive-and negative-sense RNA viruses.

How Viruses Mutate: Antigenic Drift and Antigenic Shift

7. How Viruses Mutate: Antigenic Drift and Antigenic Shift

This lesson will discuss the major ways by which viruses, notably the flu virus, mutates. We will talk about recombination, reassortment, antigenic drift, antigenic shift, and more!

Viruses: Bacteriophage Lytic and Lysogenic Cycles

8. Viruses: Bacteriophage Lytic and Lysogenic Cycles

Viruses are generally not only our enemy but also the enemy of many other organisms. Bacteriophages are viruses that infect specific bacteria. In this lesson, we'll discuss their basic structure and infection cycle.

Flu Viruses, HIV and Immune System Evasion

9. Flu Viruses, HIV and Immune System Evasion

Why is it that our immune systems can protect us from some viruses but not others? We've eradicated smallpox by using vaccines, so why do influenza and HIV remain such dangerous health risks? In this lesson about viruses, we'll explore these questions and learn how influenza and HIV continue to evade the human immune system.

Effect of Viruses on Host Cells

10. Effect of Viruses on Host Cells

In this lesson we'll be exploring how viruses exert their detrimental effects on host cells. We'll go over the cytopathological implications, such as the latent and lytic cycle, as well as oncogenesis.

Chapter Practice Exam
Test your knowledge of this chapter with a 30 question practice chapter exam.
Not Taken
Practice Final Exam
Test your knowledge of the entire course with a 50 question practice final exam.
Not Taken

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