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MICROBIOLOGY. Pathogens and Viruses. Prokaryote vs. 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.
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MICROBIOLOGY Pathogens and Viruses
Prokaryote vs. 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
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
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
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: • Lytic • Lysogenic
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)
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)