11u bio div 06

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11u bio div 06

  1. 1. Biological Kingdoms:Viruses, Viroids, and Prions
  2. 2. Think. Pair. Share.What is a virus?Give an example of a specific virus.Are viruses living or non-living?
  3. 3. Think. Pair. Share.Which Domain do viruses belong to?Which Kingdom do viruses belong to?
  4. 4. Viruses • Influenza • HIV • Chicken pox • H1N1 • Rabies • Ebola • T4 Bacteriophages
  5. 5. VirusesA virus is a small infectious particles containing geneticmaterial (DNA or RNA) within a protein capsule (capsid).
  6. 6. VirusesViruses reproduce by inserting their genetic materialinto host cells and "taking them over".The general name given to a single virus particle that isnot infecting a cell is "virion".
  7. 7. VirusesA virus is an obligate parasite; it requires a hostcell to reproduce.
  8. 8. VirusesThey are responsible for many diseases.Epidemic: Large-scale disease outbreak in a region.Pandemic: Multi-region or global disease outbreak. AIDS
  9. 9. VirusesThere are many different ways viruses can betransmitted: Disease Transmission Method rabies bites (saliva  blood) HIV body fluid exchange – excluding saliva influenza, chicken pox, airborne/direct contact common cold measles, mumps direct contact
  10. 10. VirusesThey are non-living, thus they do not fall into any taxa.Which properties of living things do they not have?
  11. 11. Differences Between Viruses and Cells Life cycle: How can something without life have a "life" cycle? Genetic material: Viruses contain RNA or DNA Organelles: enclosed by None. protein, not a membrane.
  12. 12. Differences Between Viruses and CellsSize:Viruses aremuchsmallerthan cells.Metabolism:Viruses do notmetabolize(nocytoplasm).
  13. 13. VirusesCan be classified into orders/families/genera/species:- size- shape- genetic material- single-stranded ordouble-strandedDNA/RNA- host cellsA bacteriophage (phage) is a virus that infects bacteria.
  14. 14. Virus Shapes - Cylindrical
  15. 15. Virus Shapes - Polyhedral
  16. 16. Virus Shapes - Spherical
  17. 17. Virus Shapes – Irregular (Bacterophage) capsid (top half) nucleic acid tail (bottom half) sheath tail fibres cell membrane viral RNA/DNA injected into host cell
  18. 18. Infectious CyclesA virus infects a cell by inserting its nucleic acid into it.The viral nucleic acid then enters 1 of 2 cycles:
  19. 19. Infectious CyclesLysogenic cycle: Host cell survives, but when it dividesthe virus DNA/RNA is also duplicated.
  20. 20. Infectious CyclesLysogenic cycle: Host cell survives, but when it dividesthe virus DNA/RNA is also duplicated. Viral DNA/RNA Bacterial DNAA) Attachment& Entry
  21. 21. Infectious CyclesLysogenic cycle: Host cell survives, but when it dividesthe virus DNA/RNA is also duplicated. Provirus B) Integration – viral nucleic acid becomes part of host nucleic acid
  22. 22. Infectious CyclesLysogenic cycle: Host cell survives, but when it dividesthe virus DNA/RNA is also duplicated. C) Multiplication of genome
  23. 23. Infectious CyclesLysogenic cycle: Host cell survives, but when it dividesthe virus DNA/RNA is also duplicated. D) Cell division
  24. 24. A) Attachment bacterial B) Insertion virus DNA - Virus injects its viral DNA nucleic acid into hostbacterial host cell cell E) Lysis & Release C) Replication - The host’s D) Assembly metabolism - New viral particles replicates the viral are assembled RNA/DNA
  25. 25. Infectious CyclesThe 2 cycles areinterchangeableand a virus maybe in lysogenyfor many years.
  26. 26. Infectious CyclesSometimes newly formed viruses take sections hostDNA (and host genes) with them.Transfer of genes using a virus is called transduction.
  27. 27. VaccinationsOur immune systems can create a memory forinfections that we have previously fought-off.
  28. 28. VaccinationsPreviously encountered pathogens (like viruses) aremuch more easily destroyed.
  29. 29. VaccinationsOur immune systems can create a memory forinfections that we have previously fought-off.
  30. 30. Viruses - BenefitsHow can a virus be used to benefit humans?
  31. 31. Viruses - BenefitsWe can now craft viruses that contain beneficial genesor drugs within their capsids (called viral vectors).
  32. 32. Viruses - Benefits These vectors enter the target cells and deliver their payload:Vector Contents ApplicationDrugs Ex. Chemotherapy for cancerous cells.Copies of beneficial genes Gene therapy (replacement or addition of new or better genes).Novel (new) genes Creation of GMOs (genetically modified organisms).
  33. 33. ViroidsA viroid is an infectious piece of RNA. It does not codefor anything and has no protective structure like acapsid.
  34. 34. ViroidsThese properties make them no less destructive tosimpler species.
  35. 35. PrionsA prion is a infectious protein. It has no outer structure,but damages other proteins it comes into contact with.
  36. 36. Prions
  37. 37. Prions
  38. 38. Prions
  39. 39. Prions
  40. 40. Prions
  41. 41. Prions
  42. 42. Prions
  43. 43. PrionsBovine spongiform encephalopathy (BSE, mad cowdisease) is caused by prions. Creutzfeldt-Jakob disease(DJC) is caused by prions in humans.

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