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Bacteria. “bacteria by Jonathan Coulton. Objectives. Define Bacteria, eubacteria, & archaebacteria, and note the relationships between them. Methods used to classify bacteria Describe 3 types of archaebacteria Gram-positive vs. Gram-negative bacteria Structure of a bacteria cell
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Bacteria “bacteria by Jonathan Coulton
Objectives • Define Bacteria, eubacteria, & archaebacteria, and note the relationships between them. • Methods used to classify bacteria • Describe 3 types of archaebacteria • Gram-positive vs. Gram-negative bacteria • Structure of a bacteria cell • How they move • Bacterial genetic recombination
It’s their planet, they were here first, and there’s more of them than us. • They’re microscopic prokaryotes • No nucleus, ect… The bacteria save us in War of the Worlds
Evolution • They’ve been evolving for 3.5 billion years, that’s a lot of time to turn into different species. • They’ve found ways to survive almost everywhere. Some can “hibernate” in space • Leads to interesting ideas
How many? • 40 million bacteria in a gram of dirt • 1 million in a mL of fresh water • 5x1030 bacteria in the world • Your body has 10x’s more bacteria cells than human cells in it
Classification • A lot of bacteria look pretty much alike • Group them on… • Structure, physiology, how they react to dif. Types of staining techniques • OR group them on RNA similarity
Why did the bacteria cross the microscope? • To get to the other slide.
Two kinds of bacteria • Eubacteria • Archaebacteria • More ancient group
Archaebacteria • Have weird lipids on their membranes • Have introns in their DNA • Have NO Peptidoglycan • A protein/carb mix
Extremophiles • Love extremes • No competition there • Places to salty, acidic, hot or cold, for life
Methanogens • Oxygen kills them • Live at bottom of swamps, or in sewage • Can combine O2 and CO2 into methane • Swamp gas • And in your gut • Enteric bacteria • E. Coli a facultative anaerobe: It can live with or without O2 • Obligate anaerobes: Have to live where there’s no O2
Halophiles & Acidophiles • Halophiles: Love salt • Live in the dead sea • 2nd saltiest water on Earth • 8x’s saltier than oceans • Lowest point on earth not covered by ice • 418 M below sea level
Dead Sea • King David, Herod, Jesus, John The Baptist, • Jericho is just north (oldest continually occupied town • But the sea is shrinking • People need water
Volcanic acid lake in Gorley (Kamchatka, Russia) • A crowbar will dissolve in about an hour in this lake
Acid Lake in Taal, Phillipines • Sulfuric vents at the lake’s edge
Eubacteria • Rod shaped: Bacilli • Sphere shaped: cocci • Linked in a chain: streptococci • Grape-like clusters: staphylococci • Spiral shpaed: Spirilla
Gram Stain • Gram-positive: keep the stain, show up purple • They have peptidoglycan • These bacteria make yogurt • Gram-negative: don’t take the gram stain, but do take a pink stain instead • Rhizobium: makes N2 gases usable by plants • The difference: Make dif, chemicals, react to dif antibiotics and disinfectants
Cyanobacteria • Not plants, but do photosynthesis • Heterocysts: a kind that makes Nitrogen usable for plants • If you put a lot of nitrogen into a water supply you get a population bloom • Eutrophication: all these bacteria suck up the oxygen and everything else in the water dies
Genetic recombination • Without reproducing bacteria can acquire and express new genetic info • Transformation: Bacteria take in DNA around it • Conjugation: Bacteria use pilli to make a bridge between each other and uses plasmids • Transduction: viruses carry DNA between bacteria