Bacteria bacteria by Jonathan Coulton Objectives Define Bacteria

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 m. L of fresh water 5 x 1030 bacteria in the world Your body has 10 x’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 NO Peptidoglycan • Have – 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 O 2 and CO 2 into methane – Swamp gas • And in your gut – Enteric bacteria – E. Coli a facultative anaerobe: It can live with or without O 2 – Obligate anaerobes: Have to live where there’s no O 2

Halophiles & Acidophiles • Halophiles: Love salt – Live in the dead sea – 2 nd saltiest water on Earth – 8 x’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 N 2 gases usable by plants • The difference: Make dif, chemicals, react to dif antibiotics and disinfectants

• 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 Cyanobacteria

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