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Mon May 5

Mon May 5. To Do Today Organize notebook Begin notes on viruses Warm Up - What do you know about viruses? Explain. Fact: Most of us have harmless microscopic mites living in our eyebrows. Tue May 6. To Do Today Organize notebook

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Mon May 5

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  1. Mon May 5 To Do Today Organize notebook Begin notes on viruses Warm Up - What do you know about viruses? Explain. Fact: Most of us have harmless microscopic mites living in our eyebrows.

  2. Tue May 6 To Do Today Organize notebook Begin notes on viruses Warm Up - What is a pathogen. Fact: Most experts believe that flu viruses spread mainly by droplets made when people with flu cough, sneeze or talk. These droplets can land in the mouths or noses of people who are nearby. Less often, a person might also get flu by touching a surface or object that has flu virus on it and then touching their own mouth, eyes or possibly their nose.

  3. Table of Contents for Quarter 4 Bio

  4. Virus and Bacteria – Unit # 3 Virus Vocabulary Terms Put onto notebook paper onto page 12 of notebook -- Text book pg. 434 • Virus • Pathogen • Capsid • Envelope • Glycoproteins • Bacteriophage • Lytic • Lysogenic • Prions • Viroid

  5. Viruses Create foldable for notes • Need to pick up • 2 sheets of white paper • ½ sheet • Viral diseases handout Virus video: http://www.youtube.com/watch?v=Rpj0emEGShQ

  6. What is a Virus A virus is a small infectious agent that can replicate only inside the living cells of organisms. Most viruses are too small to be seen directly with a light microscope. Viruses infect all types of organisms, from animals and plants to bacteria and archaea. Since the initial discovery of tobacco mosaic virus about 5,000 viruses have been described in detail, although there are millions of different types. Viruses are found in almost every ecosystem on Earth and are the most abundant type of biological entity. The study of viruses is known as virology, a sub-specialty of microbiology

  7. Wed/Thurs May 7&8 • To Do Today • Virus Notes in foldable • video: Life Science: Virus • Viral avengers • Warm Up – • In your own words: • What is a virus? http://cellsalive.com/howbig.htm microorganism that cannot reproduce without a host cell. It inserts genetic material into the cell and takes over its function.

  8. What is a virus? brainpop virus: http://www.brainpop.com/health/diseasesinjuriesandconditions/viruses/ • is not a living organism • is non-cellular • Consists of a nucleic acid core (DNA or RNA) and a protein coat called a capsid. • Cannot grow or replicate on their own. • Pathogen-agents that cause disease • Viruses do not grow, do not have homeostasis and do not metabolize

  9. Discovery of Viruses Near the end of the nineteenth century, scientists were trying to find the cause of tobacco mosaic disease, which stunts the growth of tobacco plants. When scientists filtered sap from infected plant they noticed that the sap could still cause uninfected plants to become infected. They called this a virus which in latin means poison. For many years they were thought to be tiny cells.In 1935, biologist Wendell Stanley of the Rockefeller Institute purified tobacco mosaic virus (TMV) and found that it crystallized, therefore it could not be living.Wendell Stanley concluded that TMV (a virus) is a chemical rather than an organism.

  10. Discovery of Viruses • Virology- Study of viruses • Viruses have existed as long as life has been on earth. • MartinusBeijerinck- (1897) Coined the name – virus meaning poison 2. Wendell Stanley (1935) Crystallized sap from the Tobacco leaves infected with tobacco mosaic virus and found a virus made of nucleic acids and protein

  11. 3. Edward Jenner – Developed small pox vaccine using milder cow pox viruses Vaccine – contains an agent that resembles a disease causing microorganism

  12. Structure of Viruses • 3 types • Plant viruses- usually helical and rod like in appearance proteins winding around a core of RNA or DNA

  13. 2. Basic animal Virus Structure – spherical and studded with receptors *some viruses can be Polyhedral meaning has MANY sides can be as many as 20 triangular faces with 12 corners.

  14. 3. A bacteriophage is a virus which infects bacteria. These viruses typically cause their hosts to die as a result of infection, which makes bacteriophages of great interest to the medical community and to scientists who cultivate bacteria. In industries where bacteria are harnessed to perform tasks such as the fermentation of foods or the production of useful chemicals, contamination with bacteriophages is a major source of concern, as the viruses can bring a process to a complete halt.

  15. Viral Reproduction Viruses are not living cells; viruses lack the capacity to metabolize on their own. Viruses MUST rely on living cells (host cells) for replication • Before a virus can replicate, it must INFECT the living cell. • EXAMPLE: An animal virus enters its host cell by endocytosis. Bacterial virus, “bacteriophage,” punches a hole in the bacterial cell wall and injects its DNA into the cell. How viruses invade your body: http://www.youtube.com/watch?v=Rpj0emEGShQ

  16. There are 2 pathways a virus can take in order to replicate itself; Lytic Cycle or Lysogenic Cycle 1. Lytic Cycle Step 1 Attachment: Virus attaches to cell, Step 2 Injection: Virus injects DNA or RNA (nucleic acid) into cell Step 3 Replication: Host cell replicates viral genes & viral proteins (A.K.A. Capsid Proteins) Step 4 Assembly: Nucleic acid and proteins assemble to form a complete virus Step 5 Release: Host cell bursts open, releasing a NEW virus

  17. Lytic Cycle

  18. 2. Lysogenic Cycle Some viruses stay inside a cell, spreading its virus through a cells natural reproduction • Lysogenic cycle allows the viral genome to replicate without destroying the host cell. In some lysogenic viruses, environmental changes can cause the lysogenic cycle to begin. • A virus in the lysogenic cycle can switch to the lytic cycle Example: Cold sore virus; virus hides in facial nerves. When body conditions are favorable (ie. Stress, sick, body weakened), the virus will cause tissue damage resulting in a cold sore or fever blister

  19. 2. Lysogenic Cycle Step 1 Attachment: Virus attaches to cell Step 2 Injection:Viral gene is inserted into host chromosome Step 3 Integration: Viral genes (DNA or RNA) combines with host DNA to become one Step 4 Cell Multiplication : Host cell divides normally, resulting in 2 new cells, each containing viral DNA. *NO damage to the host cell* * The new cells, containing viral genes, can switch to the Lytic Cycle to create MORE viruses*

  20. Lysogenic Cycle

  21. Lytic & Lysogenic CycleAnimation

  22. song “I’m a VIRUS!” • http://www.youtube.com/watch?v=kYf_Sl8W3qY

  23. To Do Today • *Outbreak video with handout • Warm UpComplete reflection– Turn in • What is the Latin meaning for virus? • Name one person responsible for discovering viruses and explain what they did. • Homework: Any Missing work due May 16! Fri May 9 So viruses make us sick, what else makes us sick? virus which in Latin means poison MartinusBeijerinck-name Wendell Stanley- TMV Edward Jenner-small pox Jonas Salk-polio vaccine BACTERIA

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