Types of Viruses: Classification and Examples

🦠 Quick Study Guide

• 🧬 Viruses are classified based on several factors, including:
• • 🔍 Type of nucleic acid: DNA or RNA
  • 📦 Structure of the capsid: Helical, icosahedral, or complex
  • 🛡️ Presence of an envelope: Enveloped or non-enveloped
  • 🎯 Host range: Animal, plant, or bacteria
• 🧬 Major Virus Types Based on Nucleic Acid:
• • 🧬 DNA Viruses: Contain DNA as their genetic material. Examples include Adenoviruses and Herpesviruses.
  • 🧪 RNA Viruses: Contain RNA as their genetic material. Examples include Retroviruses and Coronaviruses.
• 🛡️ Capsid Structures:
• • 🌀 Helical: Rod-shaped, like the Tobacco Mosaic Virus.
  • 🧊 Icosahedral: Spherical with 20 triangular faces, like Adenoviruses.
  • 🧱 Complex: Neither helical nor icosahedral, like Bacteriophages.
• ✉️ Enveloped vs. Non-Enveloped:
• • ✉️ Enveloped: Have a lipid envelope derived from the host cell membrane, like HIV.
  • 🚫 Non-Enveloped: Lack an envelope, like Poliovirus.

🧪 Practice Quiz

1. Which of the following is NOT a criterion used for classifying viruses?

   1. A) Type of nucleic acid
   2. B) Size of the virus
   3. C) Structure of the capsid
   4. D) Presence of an envelope

2. Which type of virus contains RNA as its genetic material?

   1. A) Adenovirus
   2. B) Herpesvirus
   3. C) Retrovirus
   4. D) Papillomavirus

3. What capsid structure is characteristic of the Tobacco Mosaic Virus?

   1. A) Icosahedral
   2. B) Helical
   3. C) Complex
   4. D) Spherical

4. Which of the following viruses is an example of a non-enveloped virus?

   1. A) HIV
   2. B) Influenza virus
   3. C) Poliovirus
   4. D) Coronavirus

5. Viruses that infect bacteria are known as:

   1. A) Mycoviruses
   2. B) Bacteriophages
   3. C) Zooviruses
   4. D) Phytoviruses

6. Which of the following is a DNA virus?

   1. A) Rhinovirus
   2. B) Rotavirus
   3. C) Herpes Simplex Virus
   4. D) Influenza Virus

7. What is the shape of an icosahedral capsid?

   1. A) Rod-shaped
   2. B) Spherical with 20 triangular faces
   3. C) Irregular
   4. D) Brick-shaped