1. How do bacteria reproduce?
Asexually, through a process called binary fission
One cell splits into two

2. Three Steps of Binary Fission
DNA Replication
Cell Growth
Cytokinesis
1. DNA Replication
2. Cell Growth
How does the offspring compare genetically to the original bacterial cell?
3. Cytokinesis_

3. Binary Fission Pro: super fast – can take as little as 20 minutes
Con: less genetic variation than through sexual reproduction
Bacteria obtain genetic variation through:
High mutation rates
Small parts of DNA can be exchanged through sex pili, which are like little tunnels through which the DNA can pass from one cell to another.

4. Which graph best represents a bacterial colony that is reproducing by binary fission? Explain how you know.

5. What role do bacteria play in our environment?
We know bacteria are all around us (& inside us), but what exactly are they doing?
What role do bacteria play in our environment?

6. The Importance of Bacteria

7. Roles of Bacteria
Producers: some can perform photosynthesis (or chemosynthesis)

8. Decomposers are involved in the biogeochemical cycles!
Roles of Bacteria
Decomposers: when all organisms die, their organic matter must be returned to the soil for other organisms
Decomposers are involved in the biogeochemical cycles!

10. This is a mutualistic relationship!
Roles of Bacteria
Nitrogen Fixers: some bacteria live on the roots of plants & convert nitrogen into a form that plants can use called ammonia
This is a mutualistic relationship!

11. Roles of Bacteria
Food Production: bacterial fermentation is used to make yogurt, sour cream, vinegar, buttermilk, & more!

12. This is a mutualistic relationship!
Roles of Bacteria
Human Health: E. coli bacteria living in our intestines use undigested food to produce vitamins K & B12, which we cannot make on our own. In return, we provide them with a warm environment.
This is a mutualistic relationship!

13. Probiotics Good bacteria Aid in digestion
Help to keep the bad bacteria away
Many people take probiotics as a dietary supplement. Also, probiotics are often added to food products, like yogurt.

14. Fun Fact!
On average, bacteria make up .5% of a person’s total body weight. To find out how much of you is bacteria, multiply your weight (in pounds) by .005!

15. Roles of Bacteria Disease: bacteria can cause disease in 2 ways-
Breaking down our body’s cells for food
Releasing toxins that travel through the body and damage our cells
Video

16. Probiotics are good for your digestive & immune system!
They are effective in getting rid of the bad bacteria. When you take antibiotics, you kill the bad bacteria, but you also kill the good bacteria, which could cause digestive issues.

17. Why would this be important in research?
Roles of Bacteria
Genetic Engineering: bacterial transformation
During transformation, a bacterial cell takes in DNA from outside the cell.
Why would this be important in research?

18. Bacterial Transformation
Some bacteria contain circular DNA called plasmids.
Human genes can be inserted into a bacteria cell.
The bacteria will accept the DNA as its own & express the gene.

19. Number of Colonies/Description of How it Looks
Sample Location
Number of Colonies/Description of How it Looks
Group 1
Group 2
Group 3
Group 4
Group 5
Group 6
Group 7
Group 8