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MICROBES CAUSE DISEASE!!
MessanaScience 8
Chapter 25
MICROBES = Microorganism, Microscopic OrganismBacteriaVirusParasiteFungiFound EVERYWHERE!!...water, surface of
living things, inside living organisms
DISEASECaused by a microbe entering a place in the
body where they aren’t supposed to beOrganism experiences impaired functionShow symptoms = your body’s response to
disease (fever, vomiting, joint pain, skin condition, diarrhea, etc.)
Can be infectious/communicable OR non-infectious/non-communicable
Youtube….Bacteriahttps://www.youtube.com/watch?v=kxM_9DL
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BACTERIASingle celled organisms – ALIVE!Very small, Need microscope to seeProkaryoticCan be found on most materials and surfaces –
Soil, Water, Air, etc.Can live: With/WO O2, extreme HOT/COLD.
Bacteria doubles, reproduces VERY quickly :0
Billions on your skin and in your body’s digestive track right now!
Alexander Fleming~ 1928…accidentally grew mold; led to discovery of PENICILLIN!!
Harmless bacteria on the stomach lining
E. Coli O157:H7 can make you very sick.
Streptococcus can cause strep throat.
BACTERIADifferent shapes = sphere, rod, spiralHave cell membrane, cell wall, & capsuleCytoplasm contains genetic material
floating freely + ribosomes (no nucleus or other organelles)
Has flagellum & ciliaCan move, reproduce, eat, etc.
Typical Bacterial Cell
Helpful vs. Harmful BacteriaHarmful Bacteria = Germs, Pathogens
(Greek: Pathos ~ means “suffering”)Cause disease by releasing toxins into bodyToxins are the waste products from bacteriaBacterial infections fever, swelling, rashTreat with ANTIBIOTICS! Antibiotic
resistance occurs when antibiotics are OVERUSED!!
Helpful Bacteria: (ex. found in intestines)Eat other more harmful substancesHelp plants and animals release nutrients to be
used by organismDigest food in your stomach
Clean skin has about 20 million bacteria per square inch
Youtube://www.youtube.com/watch?v=3xRttWuf3wQ
http://www.youtube.com/watch?v=4lmwbBzClAc
Viruses• VERY small!• Composed of DNA or RNA &• protein coat = CAPSID• NOT A LIVING CELL!!• Can’t reproduce, eat, move, or maintain
homeostasis• Must get inside HOST CELL to reproduce• Must fit cell membrane like “lock and key”
Virus ReplicationIf virus finds suitable living host
cell…uses the enzymes & organelles of host cell to make more viruses
DNA or RNA directs host cell to make copies of virus particle
Copies of virus cause host cell to EXPLODE!
Viruses go on to affect other cells
Youtube..https://www.youtube.com/watch?v=kYf_Sl8W
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Viruses• Cause disease in plants & animals• Viral diseases are the most widespread
illnesses in humans…minor as fevers…serious as some forms of cancer
• Transmitted: human contact, water, food, insect bites…
• Can’t treat viral infections with anything – have to run their course..
• HOWEVER~ some vaccines & anti-viral drugs used to control & prevent spread of disease (HIV/AIDS, Herpes/Shingles – Valtrax)
YouTube…Virus Rap!https://www.youtube.com/watch?v=kYf_Sl8W
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ParasitesAn organism that has a harmful relationship
with a host organismParasite lives on or in the hostSlowly weakens or kills host quicklyUsually SPECIALIZED ANATOMICALLY
(structure of the organism) & PHYSIOLOGICALLY (function of the organism).
EX: Tapeworms-so specialized = NO digestive system. Live in small intestine & absorb food directly through skin :0
Parasites….EX: lice, ticks, heartworm, mites, fleas, pin worms,
tapeworms…Tapeworms are flatworms that consist of a head, neck and a
segmented body that can grow up to 20-30 feet long with hooks on the underside to attach to intestinal walls. :0 Tapeworm infection can be caused by ingesting tapeworm eggs or larvae, which can be found in animal meats, water, soil or animal feces
PREVENTION: Wash hands!!! Cook meat! Sanitize Water!!
A Are you ready for these pictures!?
Parasites
Fish Parasite & Blood Parasite
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