About This Chapter
Introduction to Viruses - Chapter Summary
Review the basic concepts of viruses using these brief, engaging video lessons. The video lessons, taught by experts in the field of biology, provide an efficient way to review processes and classifications of viruses as you prepare to take the GRE Biology test. The lessons in this chapter cover:
- Virus structure
- Life cycle of a virus
- DNA and RNA viruses
- Virus mutation
You can watch each lesson as often as needed to be sure you retain all of the material discussed by the instructors. In addition to the videos, we provide transcripts of the lessons to give you an alternative way to review the information. Use the self-assessment quizzes at the end of each lesson to check your knowledge of the topic and get familiar with the style of questions you'll see on the exam.
GRE Biology Objectives
The GRE Biology Test is a subject matter achievement test that prospective graduate students may take to demonstrate their mastery of biology. The test covers the subfields of cellular and molecular biology, organismal biology, and ecology and evolution. Questions about viruses fall under genetics and molecular biology topics, which are part of the cellular and molecular biology subfield. These video lessons cover what you need to know about viruses for the actual test.
The GRE Biology Test consists of 190 multiple-choice questions and is provided in paper format. Genetics and molecular biology questions account for 16% to 17% of the total number of questions on the test.
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.
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.
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.
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.
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.
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.
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!
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.
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.
10. Antibiotics and Vaccines
Do you know why children must get regularly vaccinated? Have you ever wondered how an antibiotic works and why they are so widely prescribed? If so, this lesson will help you to understand how changes in medicine have almost eliminated several deadly diseases and added decades to the average person's lifespan.
11. Pathogens: Antibiotic Resistance and Virulence
Find out more about how the overuse of antibiotics could lead to some serious problems with epidemics or untreatable diseases in the future. You can also discover some of the things that make pathogens harmful and why pathogens don't cause disease in every species they infect.
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Other chapters within the GRE Biology: Study Guide & Test Prep course
- GRE Biology: History of Life
- GRE Biology: Genetic Variability, Evolutionary Processes and Consequences
- GRE Biology: Inorganic Chemistry Review
- GRE Biology: Organic Chemistry Review
- GRE Biology: Cell Structure & Function
- GRE Biology: Cell Communication
- GRE Biology: Metabolic Biochemistry
- GRE Biology: Enzymatic Biochemistry
- GRE Biology: The Cell Cycle
- GRE Biology: Biology Lab Methods
- GRE Biology: Genetic Foundations
- GRE Biology: Nucleic Acids
- GRE Biology: DNA Replication
- GRE Biology: Genetic Mutations
- GRE Biology: The Transcription & Translation Process
- GRE Biology: Bacterial Biology
- GRE Biology: Recombinant DNA Methodology
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- GRE Biology: Female Reproductive Structures
- GRE Biology: Animal Reproduction & Development
- GRE Biology: Plant Structure, Function, and Organization
- GRE Biology: Plant Reproduction, Growth, and Development
- GRE Biology: Ecosystems, Biomes, and Habitats
- GRE Biology: Ecological Interactions
- GRE Biology: Ecological Chemical Cycling
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- GRE Biology: Behavioral Ecology
- GRE Biology Flashcards