Viruses Something you don’t want to catch…

NO! 1.Viruses Made of cells Has a metabolism to grow and reproduce How do scientists classify things as living? Made of cells Has a metabolism to grow and reproduce Information stored in DNA Are viruses alive? NO!

1. Viruses 3. What do viruses and living organisms have in common? Both use nucleic acids to store genetic information in the form of DNA or RNA Both change over time (evolve)

1.Viruses 4. If viruses do not have their own metabolism to grow and reproduce, how do they survive? By hijacking living cells and using their metabolism to grow and reproduce.

2. Living or Nonliving? Characterisitic Viruses Bacteria Structure Capsid, DNA, Envelope DNA, Cell membrane, Cytoplasm Reproduction   Growth Obtains and Uses Energy?  Response to Environment?  Harms body by?  Living?

2. Living or Nonliving? Characterisitic Viruses Bacteria Structure Capsid, DNA, Envelope DNA, Cell membrane, Cytoplasm Reproduction  Host cell needed Independent Growth   Obtains and Uses Energy?  Response to Environment?  Harms body by?  Living?

2. Living or Nonliving? Characterisitic Viruses Bacteria Structure Capsid, DNA, Envelope DNA, Cell membrane, Cytoplasm Reproduction  Host cell needed Independent Growth  No - assembled  Yes Obtains and Uses Energy?    Response to Environment?  Harms body by?  Living?

2. Living or Nonliving? Characterisitic Viruses Bacteria Structure Capsid, DNA, Envelope DNA, Cell membrane, Cytoplasm Reproduction  Host cell needed Independent Growth  No - assembled  Yes Obtains and Uses Energy?  No Yes  Response to Environment?    Harms body by?  Living?

2. Living or Nonliving? Characterisitic Viruses Bacteria Structure Capsid, DNA, Envelope DNA, Cell membrane, Cytoplasm Reproduction  Host cell needed Independent Growth  No - assembled  Yes Obtains and Uses Energy?  No Yes  Response to Environment?  Harms body by?    Living?

2. Living or Nonliving? Characterisitic Viruses Bacteria Structure Capsid, DNA, Envelope DNA, Cell membrane, Cytoplasm Reproduction  Host cell needed Independent Growth  No - assembled  Yes Obtains and Uses Energy?  No Yes  Response to Environment?  Harms body by?  Disrupting Homeostasis Producing Toxins  Living?  

2. Living or Nonliving? Characterisitic Viruses Bacteria Structure Capsid, DNA, Envelope DNA, Cell membrane, Cytoplasm Reproduction  Host cell needed Independent Growth  No - assembled  Yes Obtains and Uses Energy?  No Yes  Response to Environment?  Harms body by?  Disrupting Homeostasis Producing Toxins  Living?

3. Virus Reproduction First, the virus gains entry to the cell by connecting with cell receptors. Second, the viruses’ DNA or RNA is injected into the cell.

3.Virus Reproduction c. Third, viral nucleic acid replicates and takes over the cell.

3. Virus Reproduction d. Fourth, new viral particles are packaged and released from the cell.

4. 2 types of viral infections Lytic infection- a virus enters a cell, makes copies of itself, and causes cell to burst . Lysogenic infection- a virus integrates its DNA into the DNA of the host cell, and the viral genetic information replicates along with the host cell’s DNA.

WHAT’S THE DIFFERENCE? Lytic vs. Lysogenic c. Viruses with lysogenic reproduction, lay dormant until the cell is replicated during mitosis. Lytic vs. Lysogenic WHAT’S THE DIFFERENCE?

2 Types of Viral Infection Lytic - influenza Lysogenic - herpes

CHECK POINT Lytic Lysogenic Lytic vs. Lysogenic

5. Virus Types Bacteriophages = are viruses that attack bacteria Retroviruses = viruses that use RNA to reverse transcribe DNA that integrates into the host genome. Example: HIV

6. How do you treat a virus? Remember you cannot treat a viral infection but you can prevent one by getting a vaccine. Viruses must be prevented. Wash your hands Do not share drinks, food, etc. Practice good hygeine

6.Vaccine A vaccine improves immunity to a particular disease.

6. How do vaccines work? A vaccine contains a weakened strain of the microbe. When injected into your body it stimulates your immune system to recognize it as foreign, destroy it, and remember it. So if your body encounters the full strain later, it can easily recognize and destroy it!!!!! http://health.howstuffworks.com/adam-200097.htm

Important facts about viruses SUMMARY Important facts about viruses Viruses must be produced within living cells Viruses destroy the living cells they grow in Viruses gain entry by specific receptors on the host cell