1. Warm up:
What makes us sick?

2. Goals & Objectives
Define pathogen
Distinguish between viruses and bacteria
Explain how pathogens can spread in a population

3. KEY CONCEPT Germs cause many diseases in humans.

4. Germ theory states that microscopic particles cause certain diseases.
Germ theory proposes that microorganisms cause diseases.
proposed by Louis Pasteur
led to rapid advances in understanding disease

5. Disease-causing agents are called pathogens:
Bacteria
Viruses
Fungus (fungi)
Protozoa
Parasites
Prions

6. Bacteria are single-celled organisms
release toxic chemicals that destroy cells
compete with the body’s cells for nutrients

7. Viruses are non-living pathogens
force host cells to make more viruses
made of genetic material surrounded by a protein coat

8. Fungi can be multicellular or single-celled.
take nutrients from host cells
occur in warm and damp places

9. Protozoa are single-celled organisms.
use host cells to complete their life cycles
take nutrients from host cell

10. Parasites are multicellular organisms.
grow and feed on a host
possibly kill the host

11. Different pathogen cause common infectious diseases.

12. Pathogens can enter the body in different ways.
Pathogens can be transferred by direct or indirect contact.
Indirect contact does not require touching an infected individual.
touching an infected surface
breathing in infected air

13. Direct contact requires touching an infected individual. Includes:
kissing
sexual intercourse
hand shaking
tick
Vectors carry a pathogen and transmit it into healthy cells.
ex: ticks

14. Next:
Turn to page and draw the timeline of the history of medicine and turn it in when you are finished.
You will have an exit slip today as well.

15. Exit Slip: Answer the following questions:
Define pathogen
Distinguish between viruses and bacteria
Explain how pathogens can spread in a population