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

Virus invading Bacterial Cell

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