Bacteria are single-celled microorganisms that were first observed by Anton van Leeuwenhoek in the late 1600s. Bacteria have genetic material, a cell wall, cell membrane, ribosomes, and cytoplasm, and some have flagella or take different shapes. They obtain food through photosynthesis or consuming other organisms and organic matter. Bacteria can reproduce asexually through binary fission or sexually through conjugation. Some form protective endospores when conditions become unfavorable. While some bacteria cause infectious disease, others play important roles in nature such as increasing oxygen levels and aiding food production, recycling, and health maintenance.

1. BACTERIA Notes October 19, 2009

2. Anton van Leeuwenhoek First to see what would become known as bacteria

3. Cell Structure Bacteria Are prokaryotes No nucleus Parts Genetic material Cell wall Cell membrane Ribosomes Cytoplams Flagella

4. Parts Genetic Material Located: inside the cell, but NOT in a nucleus Purpose: contains the DNA Cell Wall Located: around the outside Purpose: protects the cell

5. Parts Continued … Cell Membrane Located: inside the Cell Wall Purpose: controls what material enters and leaves the cell Ribosomes Located: in the cytoplasm Purpose: chemical factories where proteins are made

6. Parts Continued … Cytoplasm Located: inside the cell membrane Purpose: gel-like material that fills the cell Flagellum Located: on the outside of the cell Purpose: helps the cell move

7. Cell Shapes Spherical Rod-like Spiral

8. Sizes of Bacteria Vary Greatly Largest: size of a period at the end of a sentence Average: much smaller .5 to 1 nm

9. Obtaining Food Autotrophs Capture and use the sun’s light Uses energy from chemicals in its surroundings Heterotrophs Consumes other organisms or food that other organisms make

10. Respiration Definition: Process of breaking down food to release the food’s energy Most bacteria need oxygen Those that don’t need oxygen die if oxygen is present

11. Reproduction Needs for reproduction Plenty of food Right temperature Suitable conditions

12. Types of Reproduction Asexual Definition: process involving only one parent to produce offspring that are identical to the parent Type: binary fission

13. Types of Reproduction Sexual Definition: process involving two parents who combine their genetic material to produce a new organism which differs from both parents Type: conjugation

14. Endospore Formation Endospore Form when conditions become unfavorable for growth Definition: small, round, thick-walled, resting cell that forms inside the bacterial cell Contains cell genetic material and some cytoplasm

15. Role of Bacteria in Nature Increases oxygen Increases food production Helps with recycling and environmental cleanup Helps in health maintenance and medical production

16. Infectious Diseases Definition: illnesses that pass from one organism to another How they spread? Contact with: infected person infected animal contaminated object environmental sources

17. Infected Person Direct contact Hugging Kissing Touching Indirect contact Inhaling germs in the air from sneezes or coughs

18. Infected Animal Animal bites Rabies Tick bites Lyme Disease Mosquito bites West Nile Encephalitis

19. Contaminated Objects Touching or using others eating utensils Drinking from someone else’s glasses, water bottles, soda’s Touching objects that were sneezed or coughed on, then touching your eyes, mouth, or nose

20. Environmental Sources Eating foods that are contaminated salmonella Bacteria that enters a wound Clostridium tetani Toxins- poison that causes deadly diseases tetanus

21. Treating Infectious Disease Bacterial Infections Antibiotics Definition: chemical that kills bacteria without harming a person’s cells Example: penicillin Antibiotic Resistance Definition: when bacteria are able to survive in the presence of an antibiotic

22. Treating Infectious Disease Viral Infections No current cures To help: Over-the-counter medications Bed rest Drink lots of fluids Eat well-balances meals

23. Preventing Infectious Disease Vaccines Definition: substance introduced into the body to stimulate the production of chemicals that destroy specific viruses or bacteria Made by dead or altered viruses or bacteria

24. Protecting Yourself How? Keep your body healthy Eat nutritious foods Get enough sleep Get enough fluids Get enough exercise Wash your hands often Don’t share drinks, food, or utensils

25. Protecting Yourself Store food properly Keep kitchen surfaces clean Cook meat completely When you get ill Get plenty of rest Don’t come to school sick You might infect others—including me  Follow your doctors orders