Quick Quiz True or False 1. 600 different kinds of bacteria live on your skin. True 2. Saliva contains 30 different kinds of bacteria. False; 6 3. Most bacteria multiply using the process of binary fission. True 4. You can see, taste, and smell bacteria. False; cannot see with naked eye 5. Leaving foods at room temperature will slow bacterial growth. False; Place in cold environments 6. There are more microbes on your body than there are humans on the entire planet. True.
True / False con’t 7. Bacteria help our bodies with digestion and produce True: E. coli makes vitamin K and B12 8. Bacteria are used to make chocolate. True; it helps digest the hard outer covering of the bean 9. Only 50% of all bacteria are helpful. False; 99% 10. The four shapes of bacteria are circular, square, rod, and spiral. False; No square
Prokaryotes vs. Eukaryotes Prokaryotes Eukaryotes No true Nucleus Membrane bound No membrane nucleus bound organelles Membrane bound Small organelles Simple Larger Evolved 3.5 bya Complex Evolved 1.5 bya
Bacteria Can be found almost everywhere on Earth. Earliest known fossils 3.5 bya Oldest group of organisms All bacteria are prokaryotes 2 main groups (kingdoms) Eubacteria Archaebacteria
EUBACTERIA / TRUE BACTERIA Most common today Cause disease & decay Cell wall protects and determines shape. Contains peptidoglycan (carbohydrate) Example: E. coli= live in intestines of humans
Archaebacteria “ancient bacteria” Live in extreme environments Direct ancestors of eukaryotes Examples: Methanogens= oxygen free environments thick mud and digestive tracks. Halophites= Salty environments Utah’s Great Salt Lake
Prokaryotes are Identified Bytheir… 1. Shape 2. Chemical Nature 3. The way they move 4. The way they obtain energy.
Cell Walls of Bacteria Gram staining helps distinguish between the 2 different types of bacteria. Gram + Thicker peptidoglycan walls Keeps dark stain Appears purple Gram – Thinner cell wall Appears pink
Gram Staining- Use to diagnose& treat disease Gram + Gram – Harmless Harmful Important Unaffected by in food and many dairy antibiotics. Can’t penetrate industries cell wall Turns purple Turns pink Ex) Ex) E. coli Streptococcus pneumonia
Movement 1) Flagella- whip like structures 2) Lash, snake, or Flagella Position spiral 3) Glide along slime
Obtaining Energy Heterotrophs- Getenergy by consuming organic molecules made by other organisms. Autotrophs- Make their own food from inorganic molecules.
Autotrophs Photoautotrophs Use sunlight to convert carbon dioxide & water to carbon compounds and oxygen. Ex: Cyanobacteria Chemoautrotrophs Use energy from chemical reactions to make organic carbon molecules Live in darkness; ocean bottoms.
Releasing Energy Obligate aerobes- require oxygen TB Mycobacteruim tuberculosis Obligate anaerobes- NO oxygen Clostridium botulinum (canned food) Facultative anaerobes- do not require oxygen but are not killed by it. E. coli (large intestines and canned food)
Growth & Reproduction Some bacteria can divide in ~20 min 3 ways bacteria divide 1) binary fission 2) Conjugation 3) Spore formation
Bacteria Reproduction Binary fission Asexual – clones Splitting in ½ 1st growth 2nd DNA is copied 3rd splits into 2 cells
Conjugation Sexual reproduction Hollow bridge forms between 2 bacteria cells Exchange of DNA Result: increase in genetic variation
Spore Formation Formed in unfavorable conditions Can keep for months or years Produces a thick internal wall that encloses the DNA & cytoplasm Dangerous
Limiting Factors in BacteriaReproduction (Growth) Nutrients temp (freeze/ pasteurization) Moisture pH Time Sanitizing
Importance of Bacteria 1. Producers 2. Decomposers 3. Human uses
1) Producers / Nitrogen Fixers Plants & animals depend on bacteria for nitrogen Need N2 to make amino acids. N2 makes up ~ 80% of Earth’s atm Plants take N2 convert it to NH3 (ammonia) this process is known as nitrogen fixation is done by bacteria.
2) Decomposers Bacteria recycle nutrients Trees die -> Bacteria break down -> Nutrients are returned to the soil -> Process repeats
3) Human Uses Food- cheese, yogurt Beverages- wine, milk Industry- digest petroleum, clean up oil spills Medical uses- synthesize drugs E. coli- makes vitamins the body cannot make Etc.