Biology:lifestudy of
What is Life?Cellular Structure: the unit of life, one or many
Growth: cell enlargement, cell number
Evolution: long term adaptation
Behavior: short term response to stimuli
Reproduction: avoid extinction at death
Metabolism: photosynthesis, respiration, fermentation, digestion, gas exchange, secretion, excretion, circulation--processing materials and energy
Movement: intracellular, movement, locomotion
Properties of Life
Homeostasis - metabolism
All of these nutritional modes are found among prokaryotes!Eukaryotes are not as diverse in their nutritional modes.
Nutrition ModeEnergy Source
Carbon Source
Photoautotroph Light CO2
ChemoautotrophInorganic
chemCO2
Photoheterotroph
LightOrganic chem
Chemoheterotroph
Organic chemOrganic chem
Photoautotrophs - photosynthesis
• Ancient pathway, but not universal
• Cyanobacteria, Algae, Plantslight
CO2 + H2O O2 + CH2Ochlorophyll
• Purple-sulfur bacterialight
CO2 + H2S Ss + CH2Ochlorophyll
http://www.botany.hawaii.edu/faculty/webb/BOT311/Cyanobacteria/CBDivideTEM.jpg
Cyanobacterial Vegetative Cell
cell wall
cell membrane
lipid droplet
nucleoid
polyhedral body
cyanophycin
thylakoids
cyanophycean starch
vacuole
polyphosphate granule
mesosome
light reactions
cytosol
Calvin cycle and starch synthesis
photosynthesis product
RubisCO crystals!
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http://www.jgi.doe.gov/JGI_microbial/images/microbes2003/anava.jpg
Artificial coloration of TEM imageBut thylakoids shown as green would be natural!
The location of bacteriochlorophyll!
For the light reactions…
In a light microscope image:Thylakoids would not be visible, so green color would appear throughout cytosol with nucleoid region lighter in color
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http://www.bio.utexas.edu/research/utex/photogallery/Anabaena_cylindrica_629.htm
Chemoautotrophs - N metabolism
• Cyanobacteria, Rhizobium - N2 fixation
H+ + ATP + N2 NH4+
• Nitrosomonas - nitrification2 CO2 + NH4
+ NO2- + 2 CH2O
• Pseudomonas - denitrification2 CH2O + 2 NO2
- N2 + 2 CO2 + 2 H2O
Which of these processes is demonstratingchemoautotrophism?
√
http://microbewiki.kenyon.edu/images/thumb/8/89/Zdrs0232.jpg/350px-Zdrs0232.jpg
Nitrosomonas - internal membranes use NH4
+ electrons in an ETS to produce ATP ATP and protons used to reduce CO2 to CH2O
Rhizobium needs anaerobic conditions to convert N2 into NH4
+
Legumes produce heme based molecules and rapid respiration to eliminate oxygen from root nodules that house the bacterium“symbiosis”
http://www.interet-general.info/IMG/rhizobium-nodule-1.jpg
Photoheterotrophs - strange
• Bacteria: Rhodospirillum, Rhodomicrobium Light
C2H4O2- 2 CH2O
spirilloxanthin
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http://www.acadweb.wwu.edu/courses/envr429-rm/Robin/images/envr429/1_rhodospirillum_600x.jpg
Chemoheterotrophs - common!
• Escherichia coli and most eukaryotes…even plants!
CH2O + O2 CO2 + H2O + ATP
Carbohydrate, etc. provides boththe energy source
andthe carbon sourceWhat is another chemoheterotrophic organism?
Give the complete Latin binomial!
Chemoheterotrophy• Aerobic Respiration
– Glycolysis carbohydrate to pyruvate (in cytosol!)– Citric Acid Cycle pyruvate to carbon dioxide (in cytosol or matrix)
– Electron Transport and Oxidative Phosphorylation (in mesosomes or cristae)
CH2O + O2 CO2 + H2O• Anaerobic Fermentation
– Glycolysis to pyruvate (in cytosol)– Fermentive step(s) to return NAD+ to glycolysis (in cytosol)
C6H12O6 C3H3O3- C2H5OH + CO2
C6H12O6 C3H3O3- H3CCHOHCOO-
Notice how fermentation can produce gas or acids…These are just a few of the fermentive possibilities!
http://www.botany.hawaii.edu/faculty/webb/BOT311/Cyanobacteria/CBDivideTEM.jpg
Cyanobacterial Vegetative Cell
cell wall
cell membrane
lipid droplet
nucleoid
polyhedral body
cyanophycin
thylakoids
cyanophycean starch
vacuole
polyphosphate granule
mesosome
electron transport sytem and oxidative phosphorylation
cytosol
glycolysis andKrebs cycle
fuel for repiration
fuel for repiration
I thought these were only photosynthetic??
Prokaryotes do not have mitochondria…they became mitochondria!
Archea have Homeostasis
Photoautotroph Calvin Cycle (Methanococcus, Pyrococcus)Chemoautotroph acetyl-CoA or reverse TCA to fix CO2
Sulfur transporters used to drive ATP synthesisChemoheterotroph citric acid cycle, fermentation
Nutrition ModeEnergy Source
Carbon Source
Photoautotroph Light CO2
ChemoautotrophInorganic
chemCO2
Photoheterotroph
LightOrganic chem
Chemoheterotroph
Organic chemOrganic chem
Facultative and Obligate Anaerobes and Aerobes
http://biology.kenyon.edu/Microbial_Biorealm/archaea/halobacterium/halobacteria_1.jpg
3 chromosomesMain chromosome 2,015 kb191 kb replicon366 kb replicon
Replicons have genes for:DNA polymeraseTranscription factorsMineral uptake (K, PO4)Cell division
The genome has many insertion sites for foreign genes
Bacteriorhodopsin:Protein + retinalAmax 280 UV, 570 green nmenergy for proton transport and phosphorylation without photosynthesis!
Halobacterium salinarium
Aerobic RespirationUp to 5 M (25% NaCl)!Great Salt Lake, UtahRed Sea, Asia Minor
www.hawaii.edu/microbiology/ Alam/publications/PNAS96-ZHANG.pd
Cytoplasm
Periplasmicspace
CellMembraneRetinal
lsu.epfl.ch/sh/bR_full.pdf
Bacteriorhodopsin absorbs green from the visible spectrum, so what color is the pigment?Hint: it reflects the other colors of the spectrum
• Photoautotrophism
• Photoheterotrophism
• Chemoautotrophism
• Chemoheterotrophism
Which of these metabolic pathwaysis Halobacterium demonstrating?
√
Hint:
• Light for energy
• Chemicals for carbon
http://www.bact.wisc.edu/Bact303/Methanococcus.jpeg
Methanococcus jannischii
Isolated from “white smoker” hydrothermal vent2600m deep on the East Pacific Rise
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http://epr2004.sr.unh.edu/images/hires/hireswtsmoker.jpg
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http://upload.wikimedia.org/wikipedia/commons/thumb/a/ae/East_Pacific_Rise.jpg/300px-East_Pacific_Rise.jpg
East Pacific Rise
GalapagosIslands
http://www.oceanexplorer.noaa.gov/explorations/05galapagos/background/mid_ocean_ridge/media/EPR_relief_image_600.jpg
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http://www.bact.wisc.edu/Bact303/Methanococcus.jpeg
Methanococcus jannischii
Isolated from “white smoker” hydrothermal vent2600m deep on the East Pacific Rise
MethanogenObligate anaerobeH2 as energy sourceCO2 as carbon sourceCH4 as byproduct of metabolismTemperature: 50-86°C
Other archaeon species found incow rumen (first stomach)Cow belches 50 L of methane per day
What does this electron micrograph tell you?
…about cell shape?
…about motility?
• Photoautotrophism
• Photoheterotrophism
• Chemoautotrophism
• Chemoheterotrophism
Which of these metabolic pathwaysis Methanococcus demonstrating?
√
Hint:
• H2 for energy
• CO2 for carbon
http://dac.molbio.ku.dk/Sulfolobus.jpg
Sulfolobus acidocaldarius
75°C Optimum
Strict aerobe
pH 1 to 6
Oxidize Sulfur or can use Fe2+ or MnO4
2- as electron acceptors…uses glycolysis and TCA cycle
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• Photoautotrophism
• Photoheterotrophism
• Chemoautotrophism
• Chemoheterotrophism
Which of these metabolic pathwaysis Sulfolobus demonstrating?
√Hint:
• Organic chemicals for energy
• Organic chemicals for carbon
How do Archaea tolerate the heat?
• Proteins stabilized by more ionic bridges between amino acid r-groups and more-hydrophobic core amino acids
• Heat shock protein (chaperonins) refold denatured proteins…Pyrococcus 121°C for 1 hour!
• DNA depurination reduced by presence of 2,3-diphosphoglycerate.
• DNA supercoiling by reverse gyrase reduces denaturation
• Sac7d in Sulfolobus is a minor groove protein increases the melting temperature by 40°C
• Histone-like proteins help stabilize DNA as well
• Heat-resistant di-bi-phytanyl diether lipid membranes (monolayer) prevent delamination of membrane
Cell Membrane Structure
O O
O O
R
R
O O
O O
R
R
Composed of diglyceridesR group may be phosphate, sulfate, or sugarLong chain branched hydrocarbon (not fatty acid) Hydrocarbons may be C20 or C40
If C20, the membrane is a bilayer:
If C40, the membrane is a monolayer
In some species, the membrane is a mixture of both C20 and C40 diglycerides forming a mixed mono-/bi-layer
http://www.molgen.mpg.de/~ag_ribo/ag_franceschi/franceschi-projects-30S.html
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Thermus aquaticus
Gram negative bacterium (not archaeon)
Thermophile isolated from Yellowstone Hot SpringOptimum temperature 85°C
Stability of macromolecules excellentEnzymes for research or commercial useTaq polymerase is the enzyme of PCR (Polymerase Chain Reaction)
Lives near cyanobacteria which feed Thermus
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http://sci.agr.ca/crda/images/BACTERI1.JPG
• Photoautotrophism
• Photoheterotrophism
• Chemoautotrophism
• Chemoheterotrophism
Which of these metabolic pathwaysis Thermus demonstrating?
√Hint:
• Organic chemicals for energy
• Organic chemicals for carbon