Post on 07-Jan-2016
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MICROBIOLOGYPathogens and Viruses
Prokaryotevs.
Eukaryote
Prokaryotes (Bacteria)
Fossil evidence shows that bacteria have been on the earth for over 3.5 billion years
Three major shapes› Cocci (round)› Bacilli (rod-like)› Spirilla (spiral)
HARMFUL BACTERIA Some bacteria are pathogens (disease
causing) Some bacteria can make endospores,
which allow bacteria to survive long periods of time (even in bad conditions)
Diseases caused by bacteria:• Pneumonia•Strep throat•Ear infections•Salmonella•Cholera
•E. coli infections• Lyme•Tetanus•Tuberculosis• Leprosy
Lyme
Strept throat
Leprosy
HELPFUL BACTERIA In your intestine, E. coli help to
digest food Used to make yogurt Can be used to degrade oil and
toxic waste spills Used to make certain medicines Used as “gene” factories Help plants fix nitrogen Major decomposers
Decomposition over 2 weeks
Legumes with nitrogen fixing bacteria in their roots
KILLING BACTERIA Antibiotics- drugs that kill bacteria by
blocking growth or reproduction› Antibiotics do NOT kill any viruses so
they do not cure the common cold or flu
› Some bacteria are now resistant to antibiotics (ex. MRSA)
› We must always take antibiotics as prescribed!
Sterilization – destroying bacteria by heating or with chemicals
Bacilli Cocci
Spirilla
VIRUSES Viruses are particles made up of
nucleic acid (DNA and/or RNA), protein, and sometimes lipids.
Viruses are NOT living because they cannot reproduce by themselves.
All viruses enter (infect) living cells and once inside of a cell, they make more viruses.
All viruses are pathogens. Viruses are thought to have evolved
from pieces or fragments of cells.
VIRUS STRUCTURE
Viruses have a core of genetic material surrounded by a capsid (protein coat)
They are much smaller than bacteria and animal cells.
They come in many shapes.
VIRAL DISEASES Polio AIDS Influenza (the flu) Yellow fever Rabies Common cold Some cancers like cervical cancer Measles Small pox
Small Pox
Measles
Polio
Herpes
Pathogen Poster
VIRAL INFECTIONS
All cells can be infected by viruses including bacteria, animals, and plants.
Bacteriophage – a virus that infects a bacterial cell
There are two main methods of infection:1.Lytic2.Lysogenic
Bacteriophage (virus) infecting a bacterium
LYTIC CYCLE Viruses inject their genetic
material (DNA or RNA) into the host cell.
This genetic material gives instructions to make viruses.
The viruses are released by causing the cell to burst (lyse), which kills the cell.
LYSOGENIC CYCLE A virus injects its genetic material
(DNA or RNA) into the host cell. The virus’s genetic material is
mixed in with the host DNA. Viral DNA can stay embedded in
the host DNA for long periods of time.
Sometimes, the viral DNA will instruct new viruses to be made and the lytic cycle begins.
VACCINES Vaccines – made from weakened or
“killed” viruses Vaccines stimulate the immune
system to fight a specific disease Vaccines help prevent viral and
bacterial diseases from developing, but cannot help someone already infected
Examples include: HPV, MMR, Hep A
PRIONS
Prions - possibly infectious proteins that can change brain proteins causing brain damage
Diseases caused by prions progress rapidly and are almost always fatal
Diseases caused by prions include:
› Mad Cow Disease› Creutzfeldt-Jakob Disease (CJD)
Creutzfeld-Jakob Disease
Spread the word, not the germs!1) WASH your hands when they are dirty and BEFORE eating. 2) DO NOT cough into your hands. 3) DO NOT sneeze into your hands. 4) DO NOT put your fingers into your eyes, nose, or mouth.
Regular soap and water are best. Antibacterial soaps are not necessary if you have spent enough time (at least 20 seconds) cleaning your hands with regular soap and water.
(Source: www.henrythehand.com)