1 / 17

Insights into Animal Viruses: Structure, Transmission, and Impact

Explore the world of animal viruses, from their lifeless partial nature to how they spread through hosts. Discover RNA viruses, viral diseases in animals, plant viruses, and the intriguing viroids and prions. Learn about the origins of new viruses and their implications.

kinga
Download Presentation

Insights into Animal Viruses: Structure, Transmission, and Impact

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. Animal Viruses • Because viruses are lifeless partials, their spread depends on other agents. • A ( ) is an intermediate host that transfers a pathogen or parasite to another organism • Classified as ( ) or ( ) viruses, ( ) or ( )-stranded • Many have envelopes with glycoproteins that are specific for receptors. • The glycoproteins are made by the ER and added to the host cell’s membrane which envelopes the emerging viruses.

  2. Fig. 19-7 Capsid and viral genome enter the cell Capsid RNA HOST CELL Envelope (with glycoproteins) Viral genome (RNA) Template mRNA Capsid proteins ER Copy of genome (RNA) Glyco- proteins New virus

  3. Table 19-1a

  4. Table 19-1b

  5. RNA Viruses • The broadest variety of RNA genomes is found in viruses that infect animals • ( ) use ( ) to copy their RNA genome into DNA (HIV is ex.) • The viral DNA that is integrated into the host genome is called a ( ) • Unlike a prophage, a provirus remains a permanent resident of the host cell

  6. Fig. 19-8a Viral envelope Glycoprotein Capsid RNA (two identical strands) HOST CELL Reverse transcriptase HIV Reverse transcriptase Viral RNA RNA-DNA hybrid DNA NUCLEUS Provirus Chromosomal DNA RNA genome for the next viral generation mRNA New virus

  7. Fig. 19-8b Membrane of white blood cell HIV 0.25 µm HIV entering a cell New HIV leaving a cell

  8. Viral diseases in animals • Symptoms caused by - toxins - body’s defense mechanisms • ( ) – weakened or derivatives of viral particles capable of causing an immune response • ( ) not effective • Some antiviral medications interfere with viral ( ) synthesis

  9. Where do new viruses come from? • ( ) of existing viruses • The dissemination of an existing virus to a more widespread population • Or spread between species • ( ) – general outbreak of a disease • ( ) – global epidemic

  10. Fig. 19-9 (a) The 1918 flu pandemic 0.5 µm (b) Influenza A H5N1 virus (c) Vaccinating ducks

  11. Plant viruses • More than 2,000 types of viral diseases of plants are known and cause spots on leaves and fruits, stunted growth, and damaged flowers or roots • Most plant viruses have an RNA genome • Plant viral disease can spread by vertical transmission from parent plant or by horizontal transmission from an external source.

  12. Fig. 19-10

  13. Viroids and Prions: The Simplest Infectious Agents • ( )are circular RNA molecules that infect plants and disrupt their growth • ( ) are slow-acting, virtually indestructible infectious misfolded proteins that cause brain diseases in mammals • Prions propagate by converting normal proteins into the prion version • Scrapie in sheep, mad cow disease, and Creutzfeldt-Jakob disease in humans are all caused by prions

  14. Viroids in Plants

  15. Fig. 19-11 Misfolding of proteins to form prions Original prion Prion Aggregates of prions New prion Normal protein

  16. Scrapie in sheep

More Related