Ch 17: Virus Structure & Life Cycle

About This Chapter

Reaffirm your understanding of the structure and life cycle of viruses before you take the MCAT. Get ready for the Biological Sciences section of the exam with video lessons and self-assessment quizzes that provide the background you'll need to earn your best score.

MCAT Biological Science - Biology: Virus Structure & Life Cycle - Chapter Summary

The instructional videos in this chapter break down the complex study of virus structure and life cycle in units that make the subject easy to understand. You'll receive instruction in the following areas:

  • Virus basic principles
  • DNA and RNA virus replication
  • Virus mutation
  • The virus life cycle
  • HIV and AIDS as retroviridae viruses

To perform well on the Medical College Admission Test (MCAT), you'll need to be able to answer questions correctly and in a timely manner. The lessons in this chapter cover both content knowledge and practical skills. You can use the self-assessment quizzes that follow each lesson to see how much you've learned.

MCAT Biological Science - Biology: Virus Structure & Life Cycle Objectives

The structure and life cycle of viruses is covered in the Biological Sciences section of the MCAT. The MCAT is a multiple-choice exam intended to make sure candidates for admission to health profession programs have adequate skills for success in the medical field. Reasoning and scientific proficiency are the main focuses of the test's questions. The 52 questions in the Biological Sciences part of the exam require knowledge of organic chemistry along with a basic foundation in biology. In this chapter, you can meet the following learning objectives:

  • Learn virus definitions, structures and functions
  • Study virus shapes and classifications
  • Know the processes of antigenic drift and antigenic shift
  • Understand how viruses live, attack and replicate
  • Learn the bacteriophage lytic and lysogenic cycles of viruses
  • Identify the mechanisms and diseases of the retroviridae virus family

In the MCAT's Biological Sciences section, you'll need to respond to questions about reading passages and questions about research and problem-solving skills. The greatest weight is given to the exam's passages, with 39 questions related to those readings.

9 Lessons in Chapter 17: Virus Structure & Life Cycle
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.

Classification of Viruses: Viral Genome and Replication Scheme

3. 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

4. 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

5. 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

6. 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!

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

7. 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.

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.

HIV and AIDS: Mechanisms and Diseases of the Retroviridae Virus Family

9. HIV and AIDS: Mechanisms and Diseases of the Retroviridae Virus Family

Learn about one of the most famous viruses in the world: HIV. We'll also delve into a condition you've almost certainly heard of: AIDS. Finally, we'll discuss the mechanisms of how viruses in this family cause so much damage and if there's anything you can do about it.

Chapter Practice Exam
Test your knowledge of this chapter with a 30 question practice chapter exam.
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Practice Final Exam
Test your knowledge of the entire course with a 50 question practice final exam.
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