1. Bacteria and Viruses Unit 7
Marcellin Biology Notes

2. Louis Pasteur Father of Bacteriology
Developed method of Pasteurization
Pasteurization – kill some bacteria, but not all!!!

3. Pathogens
Disease Agents ( Bacteria’s food)

4. Type of Pathogens 1. Autotrophs- make their own food
2. Heterotrophs- live off other living things
3. Saphrophytes- live off dead matter

5. Types of bacteria 1. Aerobe- use and need oxygen to grow
(Ex. Diptheria, Tuberculosis, Cholera)
2. Anaerobe- die in the presence of oxygen
(Ex. Tetanus, Botulism)
Bacteria usually starts off as Spores – seeds of bacteria
Uses foods and fertile soil

6. Conditions for Bacteria Growth
Temperature
Grow best in warm temperatures ( degrees)
Moisture
Damp and humid
90 % Humidity is best
Dryness kills most bacteria

7. Conditions for Bacteria Growth
Darkness
Most bacteria grow best in darkness.
Light kills them.
Food
Some are very specific to what they feed on.
Some make their own food.
Some feed off living-dead material.

8. Identifying bacteria Bacteria exists in 3 different shapes.
1. Coccus- round, circular
2. Bacillus- rod shaped
3. Spirillum- spiral shaped

9. Identifying bacteria Bacteria also exists in 3 different arrangements.
1. Diplo- 2 joined together
2. Staphlo- Bunched together
3. Strepto- chained together

10. Naming bacteria
Arrangement + shape
Streptococcus

11. Infectious diseases: Types of Viruses
1. Bacterial
2. Plant
3. Human and animal

12. Virus vs. Bacteria Virus Bacteria Extremely small
Much larger than virus
Living and non-living
Living
Non-cell form
Cell Form
Filterable
Non-filterable
Not killed by antibiotics
Killed by antibiotics
Must feed off host
Free-living
Protein coat
Slime layer

13. How do we get infectious diseases?
1. Some are carried in food or water and enter through the mouth. Many diseases in this group center in the digestive system.

14. How do we get infectious diseases?
2. Other infections are spread through the air. Most of these diseases occur in the nose, throat, and lungs. They may be spread directly by sneezing or coughing of indirectly, by handling objects contaminated by infected people.

15. Infectious diseases
3. Certain diseases produce sores on the skin and mucous membranes. Chicken pox and smallpox are spread by such contact infection.

16. Infectious diseases
4. The skin is an effective barrier against bacteria, but if the skin is broken, wound infections may occur.
5.Human immune carriers
6. Arthropod carriers

17. How can we protect ourselves from getting diseases? Structural defenses
1. The most obvious structural defense is the skin. When unbroken, the skin is bacteria proof. Salts and acids in sweat are thought to destroy certain bacteria.

18. 2. The mucous membranes are also structural defenses
2. The mucous membranes are also structural defenses. These membranes line the mouth, breathing passages, the digestive tract, and genital tract. Mucous membrane cells secrete mucous, a slimy substance that traps bacteria on the membrane surface.

19. 3. Tears, secreted by tear glands, flow over eyes constantly
3. Tears, secreted by tear glands, flow over eyes constantly. Bacteria and other particles are washed into the tear ducts which empty into the nasal passages. Both tears and mucus contain enzymes known as lysozymes.

20. 4. The hydrochloric acid secreted by glands in the stomach wall is another defense.

21. Immune system (2nd line)
Phagocytic cells
2 types
Free- travel through body
Fixed- in organs and bones
Leucocytes
Free cells- help make pus
Lymph glands
Fluid- clean up infections

22. Antibodies
Produced by body against specific infections
Antigens
Messenger to healthy cells to protect and produce antibodies
Interferon
Strong messenger against viruses and cancer