Bacteria

Bacteria Unicellular Prokaryotes Cells walls containing peptidoglycan

Bacterial Shapes Bacilli: rod shaped Cocci: spherical Bass-ill-eye Cocci: spherical Cox-eye Spirilla: spiral, corkscrew Spy-rill-uh

What are the differences between eubacteria and archaebacteria?

Eubacteria versus Archaebacteria Cell walls of Eubacteria have lots peptidoglycans (mesh of sugar and amino acids) Archaebacteria do not Archaebacteria often live in very extreme environments (hot springs, digestive tracts, Great Salt Lake, etc.)

Metabolism Bacteria can be heterotrophic or autotrophic Remember: autotrophs are not ALL photosynthesizers! Some are chemosynthesizers (convert carbon into organic compounds)

How Bacteria Reproduce: Binary Fission When a bacterium has doubled in size, it replicates its DNA and divides in half Sexual or asexual? Identical or different daughter cells?

If bacteria are identical, how do they evolve If bacteria are identical, how do they evolve? Where does genetic variety come from (besides natural mutation rate)?

Genetic Variety in Bacteria Conjugation: cell-to-cell contact Transformation: bacterium takes up foreign DNA from surrounding environment Transduction: DNA is transferred from one bacterial cell to another by a virus

Conjugation A hollow bridge (pilus) forms between two bacteria and genes move from one cell to the other Increases genetic diversity of a population

Conjugation

Transformation Bacteria take in foreign DNA from surroundings and incorporate it into their own DNA *Remember Griffith’s experiment

Transduction DNA is transferred from one bacterium to another by a virus When new bacteriophages are made, they may contain a small amount of the host cell’s DNA

Benefits of Bacteria Some are producers that undergo photosynthesis Some are decomposers that break down dead matter to recycle the nutrients Some convert nitrogen gas to a form that can be used by plants (nitrogen fixation)

What are some dangers of bacteria?

Dangers of Bacteria Break down cells and tissues for food Example: Tuberculosis (destroys lung tissue) Release toxins (poisons) that travel through the body Example: Streptococcus releases toxins into the blood stream causes strep throat and scarlet fever

Bacterial Sexually Transmitted Diseases