Download How Diseases are Spread

2/9/2015
Differences Between Lytic and
Lysogenic Cycles
2/9/15
Warm-Up:
What is the difference between the lytic cycle
and the lysogenic cycle?
In the Lytic Cycle:
• Viral DNA destroys Cell DNA, takes over cell functions and destroys
the cell.
• The Virus replicates and produces progeny phages.
• There are symptoms of viral infection.
• Virulent viral infection takes place.
Learning Objective: Students will be able to
describe the role of bacteria and viruses in
causing disease.
In the Lysogenic Cycle:
• Viral DNA merges with Cell DNA and does not destroy the cell.
• The Virus does not produce progeny.
• There are no symptoms of viral infection.
• Temperate viral replication takes place.
How Diseases are Spread
How do Viruses spread?
• http://video.pbs.org/video/2365317280/
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airborne
direct contact
indirect contact
contamination
wound
vector-carried
insects or other arthropods
1. What helps bacteria grow?
• Moisture
• Specific ranges
– Temperature
– pH
• Nutrients
2. Endospore
In POOR GROWTH CONDITIONS>>
SURVIVAL MODE >> ENDOSPORE
FORMED to protect the nucleoid region
>> dormant
• layers of hard material around the
nucleoid region (within the plasma
membrane)
• helps a bacterium survive
unfavorable conditions
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How do pathogens cause disease?
After infection/exposure, the pathogen rapidly
multiplies during the incubation period.
• Tissue destruction
– Pathogen obtains nutrition from host cells,
destroying them in the process
• Toxin release
Antibiotics
Sir Alexander Fleming
• effective on bacteria, not on viruses
• should be prescribed by a physician
• can lose their potency
Take ALL of your prescription!
– Pathogens release poisonous substances, causing
the cells to malfunction
3. Vaccination
• inactivated vaccine
– altered virus
–weak immunity
• attenuated vaccine
– “live” virus
– stronger immunity
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