MessanaScience 8

Chapter 25

= Microorganism, Microscopic Organism Protists Bacteria Virus Parasite Found EVERYWHERE!!...water, surface

of living things, inside living organisms

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

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!

Harmless bacteria on the stomach lining

E. Coli O157:H7 can make you very sick.

Streptococcus can cause strep throat.

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.

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

• 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”

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

• 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

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!?

Transfer sun energy into energy that can be used by cells

Break down materials in

Dead/Decaying organisms

for reuse.

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