1. Disease:
Bacteria and Viruses

2. Disease Contagious diseases are caused by pathogens: Pathogen- any
disease-causing
agent, especially
bacteria and
viruses

3. Immune Response 3 lines of defense against pathogens:
Skin- acts as barrier
Injured cells send chemical signal- increases blood flow to injured area
T Cells/B Cells- weapon that destroys a specific pathogen

4. Human Immune System

5. T Cells A type of lymphocyte (or WBC) Main source of immunity
2 types: “helper” and “killer”
Helper T Cell- recognizes virus infected cell, sends signal
Killer T Cell- binds to infected cell and destroys it

6. B Cells Another type of lymphocyte Makes antibodies against pathogens
Antibody- recognize
antigens on surface of
cell, bind to it, and
destroy it

7. Antibodies recognize antigens
Antigen- foreign substance on surface of cell that triggers an immune response (attack it!)
When you fight off a disease, you develop antibodies against it to prevent getting disease again
Also get antibodies from mother’s milk

8. Different types of Immunity
Active Immunity- immune response triggered by your own body from actively having disease (usually life-long immunity)
Passive Immunity- antibodies passed from mother’s milk to child’s body (usually not permanent but protects child for some time)

9. What is a bacteria? Bacteria- prokaryotic cell (no organelles)
Unicellular
Spherical, spiral, or rod shaped
Reproduces asexually (fission)-identical copy

10. Common Diseases Caused by Bacteria: Streptococcus (Strep Throat)
Conjunctivitis (Pink Eye)
Lyme Disease (from infected Tick bites)
Anthrax

11. What is a Virus?
Virus- strand of DNA enclosed in a protein capsule that causes disease
Non-living!
Can only replicate in body of its host
Has ability to mutate into different strains (Iike influenza and different flu shots)

12. Virus Structure
DNA enclosed in capsid (protein coat)

13. Common Diseases Caused by virus: HIV (virus that causes AIDS)
Influenza (the common flu)
Smallpox (pretty much eradicated now)

14. Vaccinations
Vaccines- injection of weakened or dead virus that triggers production of antibodies
Increases
immunity to
a viral disease

15. Antibiotics
Antibiotic- substance or compound that kills, or inhibits the growth of bacteria
Ex. Penicillin
Question: Should your doctor prescribe you an antibiotic for the common flu?

16. Protect Yourself!!! Protect Yourself!
(List of ways to avoid common pathogens)