Green sea turtle Olive Ridley sea turtle

Say AH!

Tuberculosis

Ch.27 The Prokaryotic World Bacteria q=bacteria&hl=en&sitesearch= (3) q=bacteria&hl=en&sitesearch

See Table 27.2

They are everywhere. From what we know, they originated 3.5 billion years ago And they were alone on earth for 2 billion years! Prolific and Ubiquitous Their Importance? Environmentally, agriculturally, medically, evolutionarily, etc

Shapes

Ecological Impacts of Prokaryotes Recycle (Decomposers) Symbiosis: Mutualism (+ / +) Commensalism (+ / o) Parasitism (+ / -) Mutualism ex: legumes… N2 fixation

Nitrogen fixing legume root nodules

N cycle (mainly proteins) See p. 763!

Penicillin mold

Penicillin: the First Miracle Drug Alexander Fleming, a Scottish scientist, is credited with discovering the first antibiotic, penicillin. In 1928, he noticed that bacteria could not survive on a plate that contained a mold commonly found on bread. He went on to show that the effect was due to a diffusible substance made by the mold. However, penicillin was not available to the general public until the early 1940s when scientists learned how to produce and purify large amounts of penicillin.

How do antibiotics work? Two ways… Hint: think of ways to kill or hinder prokaryotic development without hurting our own Eukaryotic cells…

Gram - Gram +

Like Fig 27.3 Why are gram negative usually more threatening than gram +? What are endotoxins vs exotoxins?

s.htmlhttp:// s.html animation of E. coli infecting intestinal cells Bacteria en&sitesearch= (3) en&sitesearch Endosymbiosis c+theory&sitesearch= (1) c+theory&sitesearch

How can Photosynthetic bacteria exist and function?

What were the early bacteria on earth like? Why? When did respiration evolve? Why?

Endosymbiotic Theory Ch 26 Endosymbiosis

THE ATMOSPHERE’S EVOLUTION 1. Early atmosphere: no O2, obligate anaerobes, chemoautotrophs 2. Origin of photosynthesis: harmful UV, use sun’s E. to fix carbon or to create H+ gradient 3. Oxygen revolution: H2O used as an e- source to reduce CO2, O2 is released Iron oxides found… 4. Adaptations to the O2 rich atmosphere Ch 26

Urey/Miller experiments: Lab conditions = H20, H2, CH4, NH3 (reducing atmosphere) results: various Amino Acids Sugars Lipids Purine/pyrimidine bases

Extinctions… Permean (~250 mya) and Cretaceous (~65 mya) ** Survivors of extinctions became stock for new radiations that filled many of the adaptive zones vacated or newly created by extinctions. ** Pangaea (250 million years ago) to present day

Figure p. 530… So now… again why the 3 domian system? This figure is a peek into the first half of semester 2!!

Disease: Koch’s Postulates 1. Find pathogen 2. Isolate it, grow it 3. Infect experimental animals 4. Re-isolate the same pathogen from the infected animal Exotoxins: secreted Endotoxins: on outer membranes

Identification of different species: Important early science Shapes: Coccus, bacilli, spirilli =helices Cell walls made of: Peptidoglycan Gram staining: + purple / - pink The gram+ bacteria are purple, their outer walls are Peptidoglycan (page 505) Which type is typically more dangerous to humans? Why? How is this important?

Other characteristics Antibiotics: how do most work? __ 2 ways?__ Prokaryote Attachment: Pili, capsule Movement: 100x their body length per second! Us:1mile /9.3sec Flagella (one or many) Spirochetes Slimy chemicals to glide on (yum!) Taxis: chemotaxis, phototaxis, magnetic, gravity

Reproduction and Genetic Recombination Binary fission (cloning) No mitosis or meiosis occurs Bacteria in a bottle simulation Transformation: genes taken up from environment Conjugation: genes transferred directly from one prokaryote to another Transduction: transfer of genes to prokaryotes from viruses

Structural Comparisons with Eukaryotes No nucleus Very little compartmentalization Nucleoid region, One circular chromosome, some have plasmids (which are self replicating DNA rings) Smaller genomes, little protein w/DNA Ribosomes: selective antibiotics Endospores Some can make their own antibiotics

Then how do prokaryotes acquire their genetic variations? MUTATIONS !! reproduction rates for starting a new generation can be measured in minutes or hours = many mutations may accumulate in a short period of time.

MATH CHALLENGE If Prokaryotes reproduce every 2 hours and we every 15 years (historically based average), and prokaryotes have been around for 3.5+ billion years and we have been around 200,000 years, how much more developed and adapted are prokaryotes than humans?

Nutrition Energy source: Photo. / Chemo. Carbon source: autotroph / heterotroph Examples: photoautotroph …etc… Saprobes (saprotrophs)-absorb Parasites Nitrogen fixation

Oxygen Obligate aerobes = have to have O2 Obligate Anaerobes = have to be in an environment free of O2 Facultative = can use O2 or not Ex: facultative anaerobe obligate aerobes

“A mite makes the sea roar!” Feynman A prokaryote mite transformed (and is transforming) the earth’s entire atmosphere. EARLY METABOLISM: ATP, glycolysis, fermentation (none of these need oxygen) All are common to most all living organisms, implies an early origin in time

Systematics, Classification 3 domains: A, B, E Why are they in different domains? What are some different characteristics of Archaea and Bacteria? Methanogens, extreme halophiles, extreme thermophiles