1. Chapter 7: Lesson 1 & Lesson 3
Bacteria & Viruses
Chapter 7: Lesson 1 & Lesson 3

2. What are Bacteria?
Lesson 1

3. Characteristics of Bacteria
Microscopic
Prokaryotic: No membrane bound organelles
Can live in both living or dead organisms
Bacteria outnumber your cells 10 to 1 in your own body!
Archaea are similar to bacteria
live in extreme environments (Very Warm or Cold , No Oxygen

4. Structure of Bacteria Cytoplasm DNA Cell Membrane and Cell Wall
Ribosomes
Protective Capsule
Prevents white blood cells from surrounding bacterium

5. Sizes and Shapes of Bacteria
Much smaller than plant or animal cells
Bacteria = 1-5 micrometers
Average Eukaryotic cell = micrometers

6. Obtaining Food and Energy
Many bacteria feed on dead organisms, we call them decomposers!
Parasites: can cause tooth decay, feeding on sugars
Photosynthetic bacteria: Use light energy to make their own food, like plants.
Chemosynthetic bacteria: Use energy from Chemical reactions.

7. Aerobic vs. Anaerobic Aerobic Bacteria Anaerobic Bacteria
Need Oxygen to survive
Most bacteria are Aerobic bacteria
Do not need Oxygen to survive

8. Movement Flagella: Long whiplike structures used for movement
Twisting and spiraling as they move
Pili: Grappling hooks!

9. Reproduction
Conjugation
Binary Fission

10. Endospores Archaea

11. What are Viruses?
Lesson 3

12. Characteristics of Viruses
Strand of DNA or RNA surrounded by a layer of protein
Can infect and replicate itself in a host cell
No Cell Wall, Nucleus or any other organelles
20 to 100 times smaller than most bacteria

13. Dead or Alive? Scientists do not consider a virus to be alive Viruses:
Are not organized
Don’t respond to stimuli
Don’t use energy
Don’t grow
Don’t reproduce on their own (need a host)

14. Viral Replication

15. Viral Mutations During replication, DNA or RNA frequently mutates.
Mutations enable viruses to adjust to changes in host cells
Host cells change over time to prevent viruses from attaching to the cell
Mutations produce new ways to attach to host cells

16. Viral Diseases Chicken Pox Influenza Pneumonia Common Cold Rabies
Latent Viruses: HIV
Attacks White blood cells

17. Treating and Prevention
Immunity:
Unable to develop a disease
Antibody:
a protein that can attach to a pathogen and make it useless
Antibodies bind to viruses and other pathogens to prevent attack

18. Vaccines
Vaccine:
A mixture containing material from one or more deactivated pathogens, such as viruses.