1. Bacteria
Chapter 7.2

2. POINT > Describe bacterial cells
POINT > Describe how bacteria get energy
POINT > Explain how bacteria reproduce
POINT > Describe the role of bacteria in nature
POINT > Identify diseases caused by bacteria

3. POINT > Describe bacterial cells
Current world population:
~7,500,000,000
Bacteria cells in one human body:
100,000,000,000,000
Human body has 10x more bacteria cells than human cells!

4. POINT > Describe bacterial cells
Bacteria are prokaryotes: no nucleus
Bacteria have a circular DNA in the cytoplasm
Bacteria have a cell wall outside the cell membrane
Some bacteria have flagella for movement

5. POINT > Describe bacterial cells
Bacteria have three shapes:
1. Rod-shaped
2. Round
3. Spiral

6. CHECK:
Do bacteria cells have a nucleus?
What are three shapes of bacteria cells?
Do bacteria have a cell wall?
What are the two parts of a virus?
What does the ribosome do?

7. POINT > Describe how bacteria get energy
Some bacteria are autotrophs: they make their own food from sunlight energy or chemical energy
Some bacteria are heterotrophs: they get energy from other organisms

8. POINT > Describe how bacteria get energy
Some bacteria are aerobic: they use oxygen to perform respiration
Some bacteria are anaerobic: they cannot live in oxygen

9. POINT > Explain how bacteria reproduce
Bacteria reproduce asexually by binary fission
The cell grows, copies its DNA and divides
Some bacteria divide very rapidly (every twenty minutes)
1 cell > 1000 cells in 3 hours

10. POINT > Explain how bacteria reproduce
Bacteria reproduce sexually by conjugation
Bacteria cells exchange DNA through pili
Sexual reproduction increases variation in bacteria

11. CHECK:
What is binary fission?
What is conjugation?
What type of reproduction increases variation?
What is the name for viruses that attack bacteria?

12. POINT > Explain how bacteria reproduce
When conditions become poor (no food, too dry, too cold or too hot) bacteria can produce endospores
Endospores are single cells that can survive freezing, heat and no food for months or years

13. CHECK:
What is asexual reproduction in bacteria called?
What is sexual reproduction in bacteria called?
What is an endospore?

14. POINT > Describe the role of bacteria in nature
Bacteria are very important to life
1. Bacteria produce much of the oxygen we breathe
2. Bacteria are decomposers: they break down dead organisms

15. POINT > Describe the role of bacteria in nature
3. Bacteria help us digest food
4. Bacteria produce vitamins our bodies need
5. Bacteria in our stomach protect us from harmful bacteria
6. Bacteria are used to make cheese and yogurt

16. CHECK:
What is one way bacteria are important?
What are the 3 parts of an ATP molecule?

17. POINT > Identify diseases caused by bacteria
Bacteria cause many human diseases:
1. Cholera from unclean water
2. Plague killed about 1/3 of Europe population, almost half of China’s population (1300’s)
3. Tuberculosis kills 2,000,000 every year
4. Strep throat is a common sickness during the winter

18. POINT > Identify diseases caused by bacteria
Bacterial diseases can be treated with medicines called antibiotics: ex. penecillin
Many bacteria are becoming resistant to antibiotics
Antibiotic resistance is a growing problem worldwide
We can prevent many bacterial diseases with vaccines, washing hands, drinking clean water, and cooking foods completely

19. CHECK:
What are two diseases caused by bacteria?
What is an antibiotic?
What is antibiotic resistance?
What is a decomposer?

20. Homework:
Read 7.2 pages
S.A. page 225 #1-4
GRAS pages (All)