1 / 16

Chapter 20: Viruses and Bacteria

Chapter 20: Viruses and Bacteria. pp. 454-461, 470-471. Overview…. What is a virus? The anatomy of a virus. Types of viruses. Diseases caused by viruses. Vaccinations. What is a Virus?. Living or Non-living? Viruses were once thought to be a type of bacteria . Tobacco Mosaic Virus

arawn
Download Presentation

Chapter 20: Viruses and Bacteria

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 20: Viruses and Bacteria pp. 454-461, 470-471

  2. Overview… • What is a virus? • The anatomy of a virus. • Types of viruses. • Diseases caused by viruses. • Vaccinations.

  3. What is a Virus? • Living or Non-living? • Viruses were once thought to be a type of bacteria. • Tobacco Mosaic Virus • Discovered in 1933 by Wendell Stanley. • Isolated crystals were found to be chemical matter rather than bacteria.

  4. What is a Virus? • What is this chemical matter? • A virus consists only of nucleic acid and protein. • Viruses require living cells for reproduction, making them non-living organisms. • Definition of a Virus. • A non-living strand of nucleic acid encased in a proteincoat that can infect cells and replicate within them.

  5. CHECKPOINT What are the two main molecular components of a virus… Nucleic Acid & Protein

  6. Anatomy of a Virus • Most viruses have a protein sheath called a capsid, which surrounds the core of the virus. • The capsid in some viruses is surrounded by a lipid membrane called an envelope. The envelope allows viruses to gain entry into cells. • The envelope contains glycoproteins (proteins with carbohydrate molecules attached) • The nucleic acid found in viruses is DNA or RNA.

  7. Anatomy of a Virus Enveloped virus (HIV)

  8. Anatomy of a Virus Complex virus (Bacteriophage)

  9. CHECKPOINT Name a structure on a typical virus… • Capsid • Envelope • Protein/Glycoprotein • Nucleic Acid • Tail • Sheath

  10. Types of Viruses • Viruses come in various shapes and sizes (20-300nm). • There are four basic types of viruses: • Helical viruses • Icosahedral viruses • Enveloped viruses • Complex viruses

  11. Diseases Caused by Viruses • Tobacco Mosaic Virus (TMV) • A helical virus.

  12. Diseases Caused by Viruses • Various strains. • Infects various crops besides tobacco.

  13. Diseases Caused by Viruses • Hepatitis B Virus • An icosahedral virus. • Effects the liver and can cause inflammation, vomiting, jaundice, but rarely death. • Can lead to cirrhosis or even liver cancer.

  14. Diseases Caused by Viruses • Acquired Immune Deficiency Syndrome (AIDS) • Caused by Human Immunodeficiency Virus (HIV). • A type of enveloped virus.

  15. Diseases Caused by Viruses • Chickenpox • A type of complex virus. • “Pox” = curse.

  16. In the News… • Avian Bird Flu • Virus that some birds are adapted to, while others are not. • Can be lethal to unadapted birds. • Can infect humans in some cases.

More Related