Pathogenic Bacteria and Viruses

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Pathogenic Bacteria and Viruses The bad guys
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VIRUSES VARY IN STRUCTURE due to the different
proteins that make up the viral coat HOWEVER
the essential design is the same A core of
nucleic acid wrapped in a protein coat. A
VIRUS LACKS CELL MACHINERY therefore a
virus is not alive
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Ex BACTERIOPHAGE attacks bacteria
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BACTERIOPHAGES attack bacteria
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Ex HIV INFLUENZA These have an additional
layer - the envelope - surrounding the coat
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REPRODUCTION The LYTIC CYCLE Virus enters
host, destroying host DNA. Replicates self like
mad, until cell bursts releasing 100s of new
viruses, ready to invade more host cells.
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REPRODUCTION The LYSOGENIC CYCLE 1. Virus
enters cell its DNA/RNA is incorporated
into host DNA. 2. Host cells lives, producing
more viral DNA/RNA as it divides.
3. Virus lives on in host for life with
periodic outbreaks
The original recombinant DNA!
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A VIRUS CAN MOVE from the lysogenic to the
lytic cycle
i.e. herpes viruses have it for life, but only
the occasional outbreak
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BACTERIA ARE PROKARYOTES DNA localized (but
not bound by a membrane) in the
cytoplasm Other Structures PLASMIDS of DNA
RIBOSOMES for protein production CELL
MEMBRANE and a CELL WALL FLAGELLA for motion

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TYPICAL BACTERIA SHAPES cocci, bacilli,
spirilla
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Bacteria form ENDOSPORES when conditions are
not optimal for survival. Endospores can lie
dormant for 1000s of years!
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BINARY FISSION asexual reproduction
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CONJUGATION sexual reproduction plasmid
DNA moves between two organisms via PILI on
cell surface