1. BACTERIA

2. Structures in a Typical Bacteria
Flagella—long hairlike structures growing from a cell that aid in movement
Chromosome—usually a single, circular piece of DNA
Ribosome—used for making proteins
Plasmid—small circular piece of DNA
Cell membrane (a.k.a. plasma membrane)—separates the cell from its external environment
Pili—short, hairlike structures involved in reproduction and cell-to-cell contact
Cell wall—protects and support the cell
Capsule—located around the cell wall; bacteria with capsules are more likely to cause diseases

3. Reproduction Binary Fission:
Cell division in which the cell forms 2 identical cells
It is a form of asexual reproduction

4. Reproduction (cont.) Conjugation:
Process of exchanging genetic material though cell-to-cell contact; DNA and plasmids move through the pili from one bacterial cell to another
It is a form of sexual reproduction

5. Classification of Bacteria
Cell Shape:
Spheres—cocci
Rods—bacilli
Spirals--spirilla
Respiration:
Aerobes—use oxygen
Anaerobes—do not use oxygen

6. Classification of Bacteria (cont.)
Cell Wall Composition:
Gram positive
Gram negative
Nutrition:
Autotrophs
Heterotrophs—most bacteria are heterotrophic

7. Endospores
Thick walled structures that can resist heat, drought, and radiation
Bacterial cells can form endospores when living conditions become unfavorable

8. Transformation
Picking up and incorporating DNA from dead bacterial cells

9. Roles of Bacteria in the Biosphere
Decomposers: break down organic materials
Bioremediation: bacteria are used to rid the environment of harmful substances (i.e. oil spills)
Manufacturing: bacteria are used to ferment sugar to make cheese, yogurt and some beverages

10. Roles of Bacteria in the Biosphere (cont.)
Medicine: bacteria are used to make human proteins such as insulin
Nitrogen fixation: provides usable nitrogen for plants; ex: bacteria that live on roots of legumes
Symbiosis: relationship between 2 organisms in which at least one of the partners benefits; ex: bacteria found in the intestines of mammals help with digestion and provide vitamins

11. Pathogens Bacteria that cause diseases are called pathogens
Some pathogens use the body’s cells as food; ex: mycobacterium tuberculosis
Other pathogens release toxins that can travel throughout the body; ex: streptococcus

12. Vaccines
An injection of dead bacteria or virus will stimulate the immune system to make antibodies
The antibodies will provide immunity against the disease

13. Antibiotics
Antibiotics can work to block bacterial cell growth and reproduction
Some antibiotics, like penicillin, attack the cell wall of the bacterial cells
Penicillin makes holes in the wall causing water to rush into the cell and rupturing it