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VIRUSES

VIRUSES. AND HIV. VIRAL VOCABULARY. Bacteriophage Pathogen Lytic cycle Lysogenic cycle Prion Viroid Vaccination Immunity. Read (942-943) Vaccinations(939) STDs (1018-1020). I. ANATOMY. spikes. /DNA. * Must attach to a specific receptor site. DRAW AND LABEL. DRAW AND LABEL.

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VIRUSES

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  1. VIRUSES AND HIV

  2. VIRAL VOCABULARY • Bacteriophage • Pathogen • Lytic cycle • Lysogenic cycle • Prion • Viroid • Vaccination Immunity Read (942-943) Vaccinations(939) STDs (1018-1020)

  3. I. ANATOMY spikes /DNA * Must attach to a specific receptor site DRAW AND LABEL

  4. DRAW AND LABEL

  5. Viral Anatomy DNA or RNA Contractile Sheath

  6. Influenza Virus Strains

  7. Adenovirus A group of viruses that infect the membranes (tissue linings) of the respiratory tract, the eyes, the intestines, and the urinary tract, adenoviruses account for about 10% of acute respiratory infections in children and are a frequent cause of diarrhea.

  8. II. ARE THEY ALIVE??? • Obligate Intracellular Parasites – must get inside a host to function • Non-cellular – no cytoplasm, no membrane • No digestion, respiration, movement • REPRODUCTION!!!!!!! – they are good at it! • Not by mitosis or meiosis • Only when associated with another cell • GENETIC MATERIAL – DNA or RNA

  9. III. HOW DO THEY WORK? • See lab on Viral Replication • DNA vs. RNA VIRUS • DNA (after invasion) • Joins host DNA and produces viral RNA and viral proteins or • Remains free and produces viral RNA and viral proteins

  10. HOW DO THEY WORK (cont.) • RNA – Retrovirus • Usual flow of information – DNA>RNA>Protein • Retroviruses – RNA>DNA>into our cells DNA – uses reverse transcriptase (RT) • Join ribosomes in cytoplasm and produce viral proteins OR • With the help of RT, RNA makes DNA, which gets into the host cell’s DNA – new RNA is produced and acts as above

  11. HIV– MODERN DAY PIRATE • HIV – HUMAN IMMUNODEFICIENCY VIRUS • AIDS – ACQUIRED IMMUNE DEFICIENCY SYNDROME • 3 AREAS SERIOUSLY AFFECTED – ASIA, S. AMERICA, AFRICA • DRAW AN LABEL VIRUS • METHODS OF TRANSMISSION – BLOOD, SEMEN, VAGINAL/CERVIAL SECRETIONS, BREAST MILK, PUS • TARGET CELL OF HIV – CD4+ T HELPER CELL • OPPORTUNISTIC INFECTION – A NORMAL HARMLESS ORGANISM THAT WHEN IT ENTERS THE BODY OF A PERSON WITH A WEAK IMMUNE SYSTEM, IT CAN HARM OR KILL THEM

  12. HIV – TIME COURSE TO AIDS

  13. Obligate Intracellular Parasite – microorganisms that can only reproduce if they have entered another organism's cell - all viruses

  14. CD4 Receptor – a special receptor on a host cell's surface that HIV uses to infiltrate the cell

  15. Reverse Transcriptase –the enzyme produced by HIV and other retroviruses that allows them to synthesize DNA from their RNA, which is then integrated into the chromosomes of the host cell.

  16. T-Helper Lymphocyte –target cell in the immune system for HIV

  17. HIV virus attacking and infecting a Helper T-cell

  18. IV. REPRODUCTION • LYTIC CYCLE – REPRODUCTIVE CYCLE OF THE VIRUS – virulent (disease causing) – active phase • Absorption – attachment to receptor site • Entry – insertion of genetic material • Replication – viral parts are made – capsid and nucleic acids • Assembly – separate parts are put together • Release – digest cell membrane and escape (destroys host cell in the process

  19. LYSOGENIC CYCLE • Temperate virus – does not cause disease immediately - virus hides out • Resides in the cell without replicating. The cell may divide and result in many cells with the viral genetic material inside • Will lead to lytic cycle eventually • HIV spend the majority of the time in this cycle

  20. VIRAL REPLICATION LAB

  21. LAB ANSWERS…

  22. V. Relatives of Viruses • Viroids – short strands of RNA, no capsid • Prions – glycoproteins containing a polypeptide of 250 amino acids. • A protein capable of replication • Infectious protein…no nucleic acid • Causes Mad Cow disease, scrappies in sheep, and Kuru in New Guinea

  23. Pictures PRIONS VIROIDS

  24. MAD COW DISEASE (BSE)

  25. During WWII • Sheep parts were cooked and mixed in cow feed • Cooking didn’t destroy “scrapie” prion • Cows were infected with prion • Cows get BSE “mad cow” disease • Can it be passed to humans?

  26. Fore people of New Guinea

  27. VI. VACCINES – preventions…not a cure • Immune System – responds to foreign proteins (bacteria, virus, organ transplant, blood transfusion, bee venom, peanuts, pollen) – fever, swelling, increased mucus secretions, allergies…etc. • Inoculation – injection with a non-replicating virus or viral parts

  28. Antibodies – formed by the body to the specific foreign protein and seeks to destroy them…this is why you cannot get sick with the same cold twice • Antibodies continue to be produced indefinitely and remain to protect in the event of a second exposure to the real disease causing virus • Immunity – your body mounting a response against a foreign antigen protein...attacks and destroys the foreign substance

  29. QUIZ TOPICS • HIV/AIDS, Video stuff • Text 450-459, 942-943, 939, 1018-1020 • Vocab • Living/Nonliving WS • Lab on Reproduction • Anatomy, Reproduction, Immunity, prion vs. viroid, vaccines

  30. Jeopardy Questions - Easy • HIV Stands for…. • Your immune system responds to ______. • How soon after exposure to HIV are you infectious? • Define obligate intracellular parasite. • Name 3 diseases caused by viruses. • What is an opportunistic infection? • Why would a virus be considered nonliving? • What is the target cell for HIV?

  31. Jeopardy Questions - Easy • HIV Stands for…. HUMAN IMMUNEDEFICIENCY VIRUS • Your immune system responds to FOREIGN PROTEINS • How soon after exposure to HIV are you infectious? IMMEDIATELY • Define obligate intracellular parasite. MUST LIVE IN A HOST TO SURVIVE AND REPRODUCE • Name 3 diseases caused by viruses. MEASELS, MUMPS, RABIES, HIV, FLU, COLD, SMALL POX, CHICKEN POX • What is an opportunistic infection? ONLY HARMS WHEN IMMUNE SYSTEM IS WEAK • Why would a virus be considered nonliving? NON-CELLULAR • What is the target cell for HIV? T-HELPER LYMPHOCYTE

  32. Jeopardy Questions - Medium • What is the main difference b/t prion and a viroid? • Name 3 non-sexual fluids that carry HIV? • What do AIDS victims typically die from? • AIDS stands for? • What part of the virus attaches itself to the host cell?

  33. Jeopardy Questions - Medium • What is the main difference b/t prion and a viroid? PROTEIN VS. RNA STRAND • Name 3 non-sexual fluids that carry HIV? MOTHER’S MILK, BLOOD, PUS • What do AIDS victims typically die from? OPPORTUNISTIC INFECTIONS • AIDS stands for? ACQUIRED IMMUNEDEFICIENCY SYNDROME • What part of the virus attaches itself to the host cell? TAIL FIBERS

  34. Jeopardy Questions - Difficult • What does the AIDS test really test for? Why is it not accurate for up to 6 months? • How does a vaccine work? • Contrast lytic vs. lysogenic cycle. • What is the function of the reverse transcriptase enzyme? • Name the 3 places most seriously affected by AIDS (globally).

  35. Jeopardy Questions - Difficult • What does the AIDS test really test for? ANTIBODIES Why is it not accurate for up to 6 months? TAKES THAT LONG FOR ENOUGH TO BE PRODUCED • How does a vaccine work? EXPOSE YOU TO A NON-INFECTIOUS FORM OF THE ORGANISM AND CAUSE YOUR IMMUNE SYSTEM TO MAKE ANTIBODIES IF YOU ARE EXPOSED LATER YOUR BODY IS READY • Contrast lytic vs. lysogenic cycle. • What is the function of the reverse transcriptase enzyme? • Name the 3 places most seriously affected by AIDS (globally).

  36. Contrast lytic vs. lysogenic cycle. LYTIC IS THE IMMEDIATE REPLICATION OF THE VIRUS • What is the function of the reverse transcriptase enzyme? CONVERT RNA TO DNA • Name the 3 places most seriously affected by AIDS (globally). AFRICA, S and Central America, Asia and SE ASIA

  37. A COUPLE MORE QUESTIONS • Give 3 reasons why some one may say that a virus is alive. • Why can’t a doctor prescribe antibiotics for a virus? • Describe the brief history of Mad Cow Disease

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