Bacteria and Viruses by HC12080714461

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									Bacteria Notes Quiz
1.   Some bacteria can move by using a
     whip-like structure called a ____.
2.   Bacteria may be shaped as spheres,
     rods or ____.
3.   What is a Gram stain?
4.   How is binary fission different from
     conjugation?
5.   What is a spore?
Viruses

Unit 4
Hantavirus
Hantavirus: A Tale of Mice and
People
1.   What observations did scientists make
     that helped them determine that a virus
     caused the disease that struck in New
     Mexico?
2.   What hypothesis did scientists form
     about the cause of this disease?
3.   What conclusion did scientists make
     about how the hantavirus is spread?
Hantavirus: A Tale of Mice and
People
1.   The scientists tested the victims’ blood
     against hundreds of toxic and infectious
     agents and found that a virus was
     responsible. Then, they tested the
     victims’ blood against many known
     viruses and used the victims’ blood to
     induce symptoms in animals that were
     found to resemble hantavirus.
Hantavirus: A Tale of Mice and
People
2.   The scientists hypothesized that the
     disease was caused by hantavirus and
     spread by contact with rodents.
3.   The scientists concluded that people are
     infected by contact with the virus in
     mouse droppings.
Viruses
   Non-living particle
   Lack criteria for life
     Not a cell, no growth or development, no respiration
     Replicate only inside host cell
     Do express genes and “evolve” through mutations

   Named after disease caused or organs affected
   Bacteriophage – virus that infects bacteria
Figure 19-11 Viruses and Cells
 Section 19-2
Structure of a Virus
   Inner core – DNA or RNA
   Capsid – outer protein coat (shape)
       Some have envelopes
Figure 19-9 Virus Structures
    Section 19-2




                                      Tobacco Mosaic
         T4 Bacteriophage                  Virus
                                                                             Influenza
                            DNA                         RNA                    Virus
Head
                                                                                         RNA
                                                       Capsid     Capsid
                                                       proteins


Tail
sheath
                              Tail
                              fiber



                                                                  Surface
                                                                  proteins           Membrane
                                                                                     envelope
Ebola Virus
Types of Infections                        Coronavirus




   Lytic infection
     Virus enters cell
     Host cell makes copies of virus
     Cell bursts, releasing new viruses
Types of Infections
                                   Lysogenic infection
                                     Virus enters host cell
                                     Integrates its DNA into host
                                      cell DNA
                                     Viral DNA replicates along
                                      with host cell DNA
                                     May remain inactive for a
                                      long time
                                     When activated, the virus
Varicella (Chicken pox) virus         enters the lytic cycle
Figure 19-10 Lytic and Lysogenic Infections
Virus Replication Cycles
Retrovirus
   Contains RNA as its
    genetic material
   Uses reverse
    transcriptase to make
    DNA from its RNA,
    which is then
    integrated into host
    DNA
   Ex: HIV
                            HIV-1 budding from lymphocyte
Other viruses
   Oncogenic virus (tumor virus): can cause
    cancer
     Human   papilloma virus, Hepatitis B virus
   Plant virus: affects only plants, some
    cause disease, some don’t cause any
    harm
     Tobacco   mosaic virus
Common Diseases Caused by Viruses
 Section 19-3




     Type of Virus       Nucleic Acid   Disease
     Oncogenic viruses   DNA            Cancer
     Retrovirus          RNA            Cancer, AIDS
     Adenoviruses        DNA            Respiratory infections
     Herpesviruses       DNA            Chickenpox
     Poxviruses          DNA            Smallpox
Hepatitis A



                       Hepatitis A Virus



Hepatitis A Jaundice
Smallpox




 Smallpox lesions on face   Last known person to have smallpox
Influenzae A Virus
1918 Flu




   NOVA ScienceNOW, November 21, 2006
How viruses travel
1.   What kinds of diseases might be transmitted
     this way?
2.   What kind of behavior did the liquid exchange
     represent?
3.   How would the results have been different if
     you exchanged liquids three more times?
4.   How would the results have been different if
     some students chose not to exchange liquids
     at all?
5.   Why is it important to understand how
     pathogenic viruses travel?
Cover your mouth!




                    CDC/ Brian Judd

								
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