1. Bacteria and Viruses
Our Microscopic World

2. BACTERIA smallest, simplest organism, unicellular
Most abundant organism
Prokaryotic cell…very simple, NO nucleus, ribosomes, cytoplasm, circular DNA, cell membrane, some have cell walls

3. BACTERIA CLASSIFICATION
Archaebacteria
“old” bacteria
Found in inhospitable conditions
Three types
1. Heat lovers…found in hot springs, paint pots, ocean vents
2. Methane makers…found in swamps
3. Salt lovers…found in high salt environments…ie: Dead Sea
Eubacteria
Most common
Found everywhere
Grouped by how obtain food
1. producers…make own food
2. decomposers…consumer that breaks down matter to obtain nutrients
3. parasites…consumer that obtain nutrients by feeding off other organisms

4. SHAPES 1. COCCI…Sphere shaped 2. BACILLI…bar shaped
3. SPIRILLA…spiral shaped

5. Bactria Reproduction… Binary Fission
Bacteria reproduce in a process called BINARY FISSION
1. Cell grows larger
2. DNA replicates and attaches to the cell membrane
3. The DNA and its copy separate as the cell grows larger
4. The cell splits in two.
* each new cell contains identical DNA

6. For MOST bacteria…Ideal conditions for reproduction are warm and moist
For MOST bacteria…Ideal conditions for reproduction are warm and moist. When conditions are not ideal, some will survive by forming and ENDOSPORE, a hard protective covering. Many bacteria can survive boiling, freezing, and extremely dry conditions. When conditions become favorable again, endospores can break open and bacteria can become active again.

7. Good Bacteria
Nitrogen Fixing Bacteria… takes nitrogen from the air and change it to a useable form plants can use Decomposing Bacteria… breaks down dead matter so nutrients are available for new plants Bioremediation… bacteria converts pollution into harmless chemicals … used to clean up wastes, oil spills and remove toxins from soils

8. Good Bacteria…continued
Genetically Engineered Bacteria…
To produce…
medicine, insecticides, cleaners, adhesives and some foods
Medicines such as…
ANTIBIOTICS…chemicals used to kill bacteria and other microorganisms
INSULIN so diabetics are able to process sugars and carbohydrates
Foods… (BLANK)
to help make some sausage, some dairy products (cheese/yogurt/cottage cheese, etc), pickles

9. Bad Bacteria Pathogenic Bacteria (Cause disease)
They invade the host and obtain nutrients from the host, weakening the host and causing damage to the host
Most can be treated with ANTIBIOTICS
Human Diseases caused by Bacteria…
cavities, ear infections, strep throat, food poisoning
Can cause disease in animals but also in plants, protists, fungi and other bacteria!

10. VIRUSES
Particles that imitate life…

11. VIRUSES Microscopic particle that invades a cell, often destroying it
Found everywhere
Many diseases are caused by viruses
Contains a protein and nucleic acid (genetic material)
DO NOT eat, grow, use air
Can only reproduce with HELP from a host
The are NOT living!

12. VIRUS CLASSIFICATION Viruses are classified in many ways…
Type of disease
Life cycle
Type of genetic material
Shape

13. Virus Shapes Crystal…ex: polio virus Spherical…ex: influenza, HIV
Cylinder…ex: tobacco mosaic virus
Spacecraft…ex: bacteriophage

14. VIRAL REPRODUCTION Viruses MUST have a host to reproduce
The reproduction process is
the LYTIC CYCLE
A. Virus finds a host cell
B. Virus enters cell OR DNA is injected into cell
C. Virus’ DNA takes over control of the cell
D. Cell produces new viruses
E. New viruses break out of the cell and invade other cells

15. Diseases Caused by Viruses
Common cold
Influenza
Polio
Chicken pox
Measles
Mumps

16. VACCINES Vaccines are used to build up an individual’s immune
system by…
1. Inject a weakened or “dead” virus into the body
(the shot)
The body’s immune system recognizes the invader and begins to build up antibodies (an army) to fight the virus
The body’s immune system is able to build up the antibodies to fight the virus because the virus is not very strong.
4. The next time the virus in introduced into the body, the body recognizes the virus and already has the antibodies (army) to fight the virus.
Common vaccines: polio, measles/mumps/rubella (MMR), influenza, chicken pox, hepatitis

17. Infectious vs Non-infectious
Non-infectious Disease…a disease that is not transmitted from person to person Infectious Disease…a disease that is caused by a pathogen (bacteria, virus, fungus, protist) can generally be transferred from person to person

18. Protists Microscopic organisms Found commonly in pond water
Cause dysentery
Don’t drink water from Mexico

19. Fungi
Cause fungal infections
Yeast infections
Athletes foot