MICROBES CAUSE DISEASE!! Messana Science 8 Chapter 25

MICROBES = Microorganism, Microscopic Organism Protists Bacteria Virus Parasite Found EVERYWHERE!!...water, surface of living things, inside living organisms

DISEASE Caused by a microbe entering a place in the body where they aren’t supposed to be Organism experiences impaired function Show symptoms = your body’s response to disease (fever, vomiting, joint pain, skin condition, diarrhea, etc.) Can be infectious/communicable OR non-infectious/non-communicable

Harmless bacteria on the stomach lining E. Coli O157:H7 can make you very sick. BACTERIA Harmless bacteria on the stomach lining Single celled organisms – ALIVE! Very small, Need microscope to see Prokaryotic Can be found on most materials and surfaces – Soil, Water, Air, etc. Billions on your skin and in your body’s digestive track right now! Streptococcus can cause strep throat.

BACTERIA Different shapes = sphere, rod, spiral Have cell membrane, cell wall, & capsule Cytoplasm contains genetic material floating freely + ribosomes (no nucleus or other organelles) Has flagellum & cilia Can move, reproduce, eat, etc.

Typical Bacterial Cell

Helpful vs. Harmful Bacteria Harmful Bacteria = Germs, Pathogens Cause disease by releasing toxins into body Toxins are the waste products from bacteria Bacterial infections  fever, swelling, rash Treat with ANTIBIOTICS! Helpful Bacteria: Eat other more harmful substances Help plants and animals release nutrients to be used by organism Digest food in your stomach

Clean skin has about 20 million bacteria per square inch

Viruses VERY small! Contains protein coat = CAPSID Contains DNA or RNA NOT A LIVING CELL!! Can’t reproduce, eat, move, or maintain homeostasis Try to get inside HOST CELL to reproduce Must fit cell membrane like “lock and key”

Virus Replication If virus finds suitable living host cell… 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

Viruses Shaped life on Earth Cause disease in plants & animals Affected evolution by redistributing genes Can protect organisms from environmental contaminants Can’t treat viral infections with anything – have to run their course

Parasites An organism that has a harmful relationship with a host organism Parasite lives on or in the host Slowly weakens or kills host quickly EX: protists, bacteria, ticks, tapeworms, heartworm, mites, fleas, athlete’s foot, fungi, invertebrate insects Are you ready for these pictures!?

Parasites

Fish Parasite & Blood Parasite

Transfer sun energy into energy that can be used by cells PRODUCERS Transfer sun energy into energy that can be used by cells

Break down materials in Dead/Decaying organisms for reuse. DECOMPOSERS Break down materials in Dead/Decaying organisms for reuse.

PARASITES LIVE ON HOSTS, may not affect host OR may be HARMFUL to host.

http://www.mixbook.com/photo- books/nature/producers-consumers-and- decomposers-3724805

J:\The Parasite Picture Gallery.mht