Bacteria and Viruses Unit 7 Marcellin Biology Notes

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

Pathogens Disease Agents ( Bacteria’s food)

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

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

Conditions for Bacteria Growth Temperature Grow best in warm temperatures ( 70- 85 degrees) Moisture Damp and humid 90 % Humidity is best Dryness kills most bacteria

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.

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

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

Naming bacteria Arrangement + shape Streptococcus

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

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

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.

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.

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

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

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.

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.

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.

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

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

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