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Viruses

Viruses. Virus “intracellular parasites”. small infectious agent that can replicate only inside the living cells of organisms. Chicken Pox and Shingles Virus. Virion : an entire virus particle. Consists of: DNA or RNA Protein Coat – called a capsid

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Viruses

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  1. Viruses

  2. Virus“intracellular parasites” • small infectious agent that can replicate only inside the living cells of organisms

  3. Chicken Pox and Shingles Virus

  4. Virion: an entire virus particle • Consists of: • DNA or RNA • Protein Coat – called a capsid • Sometimes a lipid envelope around the protein coat • You Tube Lytic Cycle (2:17)

  5. Bacteriophage Virus • capsid

  6. Sometimes glycoprotein spikesto help the virus enter and exit the host cell

  7. LYTIC INFECTION • Animation of a Lytic Infection • McGraw Hill Life Cycle of a T2 Phage

  8. HIV • The Human Immunodeficiency Virus (HIV) • Can lead to AIDS (acquired immunodeficiency syndrome)

  9. HIV INFECTION • HIV infection: a retrovirus (high level) • Shows receptors and how anti-viral drugs can be effective HIV budding from a lymphocyte

  10. Lytic Infection

  11. Examples Lytic Infections • Common Cold • Influenza • Rabies • TMV (tobacco mosaic virus)

  12. Lysogenic Infection

  13. Temperate Viruses • Also called lysogenic viruses • are those that reproduce without killing their host cell.

  14. Common Lysogenic Virus • Herpes (genital and cold sore) • Papilloma HPV (cervical cancer) • Retrovirus • Hepatitis B • Chicken Pox

  15. Retroviruses • Retroviruses use RNA instead of DNA as their nucleic acid core. • also contain the enzyme reverse transcriptase

  16. Retrovirus Examples • HIV • Rous sarcoma (first one discovered) • Leukemia viruses

  17. Viroids • Viroids are naked circular RNA (no protein coat) molecules that are several hundred nucleotides long. • Infect plants

  18. Viroid Attack on Potatoes • Used to make varieties in flowers

  19. Prions • a form of a normal protein that is not folded correctly. • Cause degenerative brain disease

  20. Mad Cow Disease • BSE = bovine spongiform encephalitis • It's ...BSE You Tube • Can cause CJD in humans

  21. CJD • Creutzfeldt-Jakob disease (CJD) is a form of brain damage that leads to a rapid decrease of mental function and movement. • You Tube The BSE Prion and Variant CJD

  22. Vaccines • “Harmless” variants or derivatives of pathogenic microbes that stimulate the immune system to make antibodies against the pathogen.

  23. Edward Jenner First Vaccine(for smallpox) • Gave cowpox to his son first • Lots of people were getting smallpox

  24. BACTERIA • Prokaryotes • Most of its DNA is in a single chromosome

  25. Bacteria Can Transfer DNA in 3 Ways • 1. Transformation – uptake of foreign DNA from the surrounding environment • 2. Transduction – transfer of bacterial genes by a bacteriophage • 3. Conjugation – physical union of two bacterial cells as they “mate”

  26. Transformation

  27. Transduction

  28. Conjugation

  29. Bacterial Plasmids • F Factor = fertility plasmid

  30. F Plasmid • Resistance Plasmid • Carry genes to destroy antibiotics

  31. Identifying Bacteria • McGraw Hill Prokaryotic Cell Shapes

  32. Can you name these shapes?

  33. Can you name these shapes? • A Bacilli with and without flagella • B Streptococci • C Staphylococci • D Diplococci • E Spirochete • F Club rod • G Filamentous • H Streptobacilli

  34. Spores • dormant, tough, and non-reproductive structure produced by certain bacteria

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