1. MICROBES CAUSE DISEASE!!
Messana
Science 8
Chapter 25

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

3. 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

4. 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.

5. 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.

6. Typical Bacterial Cell

7. 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

8. Clean skin has about 20 million bacteria per square inch

9. 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”

10. 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

11. Virus invading Bacterial Cell

12. 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

13. 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!?

14. Parasites

15. Fish Parasite & Blood Parasite

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

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

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

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

20. J:\The Parasite Picture Gallery.mht