Viruses

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Viruses Bacteria and Biotechnology
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(at most several hundred genes)
(capsid)
Viruses Are Noncellular! (Nonliving)
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ds RNA
ss RNA
ds DNA
ss DNA
I
II
III
IV-VI
Drosophila X
smallpox (variola)
Influenza
Maize streak
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Envelopes
Herpes
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Retrovirus
Animal cell infection
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Super HIV Strain Rattles Experts
                                                  
                                                  
                                                  
          AIDS scientists are studying viruses
from two patients to see if either are the
source of a more aggressive and more
drug-resistant strain of HIV.  They are
concerned about a new strain of HIV that rapidly
progresses from infection to AIDS. Though the
cases have been few and isolated, at-risk
communities are alarmed and frightened by the
recent discoveries and developments.
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Viroids
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PrPSc
PrPc
From Dr Jekyll to Mr Hyde The prion protein
exists in two forms. The normal, innocuous
protein (PrPc) can change its shape to a
harmful, disease-causing form (PrPSc). The
conversion from PrPc to PrPSc then proceeds via
a chain-reaction. When enough PrPSc proteins
have been made they form long filamentous
aggregates that gradually damage neuronal
tissue. The harmful PrPSc form is very resistant
to high temperatures, UV-irradiation and strong
degradative enzymes.
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Archaea
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Green and Purple Bacteria
Autotrophic
Photosystem I only!
No oxygen released
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Cyanobacteria
"blue-green algae"
Autotrophic
Photosystems I and II
Give off oxygen
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Saprotroph
(decomposer)
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nitrogen fixation
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Transduction
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Figure 9. Increase of bacteria resistant to 3
antibiotics over time and cartoon of
Superbacteria with many resistance plasmids.
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Plasmids
Episomes
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According to the Jacob-Monod model of the lac
operon, the regulator gene does which of the
following? a. Specifies the amino acid sequence
of the enzyme. b. Controls the activity of
histones. c. Determines whether promoter genes
will be translated. d. Directs the synthesis of
a repressor protein. e. Produces corepressor
substances.
Answer d
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zinc-finger
helix-turn-helix
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