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Warm Up

Warm Up. Monday, March 18, 2013 Which process copies a strand of DNA (DNA to DNA)?. Virus Notes. Objectives. List the major components of a virus. 2) List the steps involved in virus replication.

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Warm Up

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  1. Warm Up • Monday, March 18, 2013 • Which process copies a strand of DNA (DNA to DNA)?

  2. Virus Notes

  3. Objectives • List the major components of a virus. 2) List the steps involved in virus replication. 3) Describe a real world scenario in which viruses have had a negative impact on human lives.

  4. Viruses • NOT living organisms • Infects host cells • Inject their genetic material into host • Needs host in order to replicate

  5. Parasites = depend entirely upon another living organism to survive, harming organism in process • Viruses = parasites • Take advantage of hosts respiration, nutrition, & all other functions

  6. Virus Genetics • Composed of DNA or RNA core • Surrounded by protein coat • Simplest: few genes • Most complex: >100 genes

  7. Capsid = Protein coat that surrounds DNA/RNA • Enable virus to enter host cell • Bind to receptors on surface of cell • “Trick” cell into letting it in • Once inside, viral genes expressed

  8. Cold Viruses

  9. Flu Virus

  10. Viruses Specific • Bind to specific proteins on host cell’s surface • Why does it matter? • Infect specific cells • Infect specific organisms • Example: • HIV infects humans • Parvovirus infects dogs, wolves, & foxes

  11. Bacteriophage = virus that infects a bacterial cell • Structure: • Head = contains DNA • Neck • Collar • Sheath • Tail Fiber • Base Plate

  12. Lytic Infection • Virus enters cell • Virus copies itself • Cell bursts

  13. Lytic Cycle • 5 Stages: • Attachment (a) - virus attaches itself to host cell • Injection (a & b) - virus inserts its genetic material into host cell • Integration (c) - genetic material tells the cell what to do • Replication (d) - host cell builds parts of virus  Assembly (d) - cell assembles replicated parts into progeny viruses  5) Lysis (e)- cell breaks open & ea. replicated virus can  infect other cells

  14. Lysogenic Cycle • Latent period extends cycle • Viral DNA becomes part of host chromosome for a time

  15. Lysogenic Infection • Virus enters (a-1) • Integration: Virus integrates viral DNA w/ host cell DNA (a-2) • Viral DNA is replicated (when host cell replicates DNA) (a-3) • Host cell completes mitosis & makes other cells infected w/ virus(a-4) ***Difference: Host cell does NOT burst!!! (b)***

  16. Prophage • Viral DNA that’s embedded in the host’s chromosome (DNA)

  17. Retrovirus = contain RNA as the hereditary material in place of the more common DNA • Genetic information copied backward • RNA to DNA (usually other way) • May remain dormant & wait for right conditions to become active • Dormant = not active (like sleeping)

  18. Retrovirus • Example: • virus that causes AIDS • (acquired immune deficiency syndrome)

  19. Viral Diseases • CanNOT be treated w/ antibiotices • Must PREVENT infection • Vaccinations • Stopping spread

  20. Other Viral Diseases • Chicken Pox • Symptoms: fever and weakness, red, itchy rash • Spread By: contact w/ rash • Prevention: Vaccine

  21. Other Viral Diseases • Measles • Symptoms: High fever, sore throat, cough, rash, sneezing, swollen eyelids, whiter spots on cheek lining • Spread By: Droplet inhalation • Prevention: Vaccine

  22. Other Viral Diseases • West Nile • Symptoms: Fever, headache, body ache- • Spread By: Bite from an infected mosquito • Prevention: Mosquito repellant, avoid going outside at dawn & dusk, avoid standing water

  23. AVID Thinking Strategies • WANTED Virus Poster (2 colors) • Include: • The words “WANTED” at the top • Virus name • Drawing of virus or picture that depicts aspect of virus life cycle (Ex: mosquito for west nile) • Symptoms that are seen in infected host • How virus spread • Prevention/Treatment

  24. Warm Up • Tuesday, March 19, 2013 • Which process creates a strand of RNA (DNA to RNA)?

  25. Germ Warfare Reading & Summaries

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