Transcript light

Biology:
life study of
What is Life?
Properties of Life
Cellular Structure: the unit of life, one or many
Metabolism: photosynthesis, respiration, fermentation,
digestion, gas exchange, secretion, excretion,
circulation--processing materials and energy
Growth: cell enlargement, cell number
Movement: intracellular, movement, locomotion
Reproduction: avoid extinction at death
Behavior: short term response to stimuli
Evolution: long term adaptation
Homeostasis - metabolism
Nutrition Mode
Energy Source
Carbon Source
Photoautotroph
Light
CO2
Chemoautotroph
Inorganic chem
CO2
Photoheterotroph
Light
Organic chem
Chemoheterotroph
Organic chem
Organic chem
All of these nutritional modes are found among prokaryotes!
Eukaryotes are not as diverse in their nutritional modes.
Photoautotrophs - photosynthesis
• Ancient pathway, but not universal
• Cyanobacteria, Algae, Plants
light
CO2 + H2O  O2 + CH2O
chlorophyll
• Purple-sulfur bacteria
light
CO2 + H2S  Ss + CH2O
chlorophyll
Cyanobacterial Vegetative Cell
cell wall
mesosome
cell membrane
cyanophycean starch
photosynthesis product
cyanophycin
vacuole
lipid droplet
polyphosphate granule
thylakoids
light
reactions
nucleoid
cytosol
Calvin cycle and
starch synthesis
http://www.botany.hawaii.edu/faculty/webb/BOT311/Cyanobacteria/CBDivideTEM.jpg
polyhedral body
RubisCO crystals!
But thylakoids shown as green would be natural!
The location of bacteriochlorophyll!
For the light reactions…
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
http://www.jgi.doe.gov/JGI_microbial/images/microbes2003/anava.jpg
Artificial coloration of TEM image
In a light microscope image:
http://www.bio.utexas.edu/research/utex/photog
allery/Anabaena_cylindrica_629.htm
Thylakoids would not be visible, so green color
would appear throughout cytosol with nucleoid
region lighter in color
Chemoautotrophs - N metabolism
√
• Cyanobacteria, Rhizobium - N2 fixation
H+ + ATP + N2  NH4+
• Nitrosomonas - nitrification
2 CO2 + NH4+  NO2- + 2 CH2O
• Pseudomonas - denitrification
2 CH2O + 2 NO2-  N2 + 2 CO2 + 2 H2O
Which of these processes is demonstrating
chemoautotrophism?
Nitrosomonas -
http://microbewiki.kenyon.edu/images/thumb/8/89/Zdrs0232.jpg/350px-Zdrs0232.jpg
internal membranes use NH4+ electrons in an ETS to produce ATP
ATP and protons used to reduce CO2 to CH2O
http://www.interet-general.info/IMG/rhizobium-nodule-1.jpg
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”
Photoheterotrophs - strange
• Bacteria: Rhodospirillum, Rhodomicrobium
Light
C2H4O2-  2 CH2O
spirilloxanthin
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
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 both
the energy source
and
the carbon source
What 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-  H3CCHOHCOONotice how fermentation can produce gas or acids…
These are just a few of the fermentive possibilities!
Cyanobacterial Vegetative Cell
I thought these were only photosynthetic??
cell wall
mesosome
electron
transport sytem
and oxidative
phosphorylation
cell membrane
cyanophycean starch
fuel for repiration
cyanophycin
vacuole
lipid droplet
fuel for repiration
polyphosphate granule
thylakoids
nucleoid
cytosol
glycolysis and
Krebs cycle
polyhedral body
http://www.botany.hawaii.edu/faculty/webb/BOT311/Cyanobacteria/CBDivideTEM.jpg
Prokaryotes do not have mitochondria…they became mitochondria!
Archea have Homeostasis
Facultative and Obligate Anaerobes and Aerobes
Nutrition Mode
Energy Source
Carbon Source
Photoautotroph
Light
CO2
Chemoautotroph
Inorganic chem
CO2
Photoheterotroph
Light
Organic chem
Chemoheterotroph
Organic chem
Organic chem
Photoautotroph Calvin Cycle (Methanococcus, Pyrococcus)
Chemoautotroph acetyl-CoA or reverse TCA to fix CO2
Sulfur transporters used to drive ATP synthesis
Chemoheterotroph citric acid cycle, fermentation
Halobacterium salinarium
http://biology.kenyon.edu/Microbial_Biorealm/
archaea/halobacterium/halobacteria_1.jpg
Aerobic Respiration
Up to 5 M (25% NaCl)!
Great Salt Lake, Utah
Red Sea, Asia Minor
3 chromosomes
Main chromosome 2,015 kb
191 kb replicon
366 kb replicon
Replicons have genes for:
DNA polymerase
Transcription factors
Mineral uptake (K, PO4)
Cell division
The genome has many insertion sites
for foreign genes
Bacteriorhodopsin:
Protein + retinal
Amax 280 UV, 570 green nm
energy for proton transport and
phosphorylation without
photosynthesis!
Periplasmic
space
Retinal
Cell
Membrane
lsu.epfl.ch/sh/bR_full.pdf
Cytoplasm
www.hawaii.edu/microbiology/ Alam/publications/PNAS96-ZHANG.pd
Bacteriorhodopsin
absorbs green from the
visible spectrum, so
what color is the
pigment?
Hint: it reflects the
other colors of the
spectrum
Which of these metabolic pathways
is Halobacterium demonstrating?
• Photoautotrophism
√
• Photoheterotrophism
• Chemoautotrophism
• Chemoheterotrophism
Hint:
• Light for energy
• Chemicals for carbon
Methanococcus jannischii
Isolated from “white smoker”
hydrothermal vent
2600m deep on the East Pacific Rise
http://epr2004.sr.unh.edu/images/hires/hireswtsmoker.jpg
http://www.bact.wisc.edu/Bact303/Methanococcus.jpeg
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Galapagos
Islands
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
http://upload.wikimedia.org/wikipedia/commons/thumb/a/ae/East_Pacific_Rise.jpg/300px-East_Pacific_Rise.jpg
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
http://www.oceanexplorer.noaa.gov/explorations/05galapagos/background/mid_ocean_ridge/media/EPR_relief_image_600.jpg
Methanococcus jannischii
Isolated from “white smoker”
hydrothermal vent
2600m deep on the East Pacific Rise
http://www.bact.wisc.edu/Bact303/Methanococcus.jpeg
What does this electron
micrograph tell you?
…about cell shape?
…about motility?
Methanogen
Obligate anaerobe
H2 as energy source
CO2 as carbon source
CH4 as byproduct of metabolism
Temperature: 50-86°C
Other archaeon species found in
cow rumen (first stomach)
Cow belches 50 L of methane per day
Which of these metabolic pathways
is Methanococcus demonstrating?
• Photoautotrophism
• Photoheterotrophism
√
• Chemoautotrophism
• Chemoheterotrophism
Hint:
• H2 for energy
• CO2 for carbon
Sulfolobus acidocaldarius
75°C Optimum
Strict aerobe
pH 1 to 6
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
http://dac.molbio.ku.dk/Sulfolobus.jpg
Oxidize Sulfur or can use
Fe2+ or MnO42- as electron
acceptors…uses
glycolysis and TCA cycle
Which of these metabolic pathways
is Sulfolobus demonstrating?
• Photoautotrophism
• Photoheterotrophism
• Chemoautotrophism
√
• Chemoheterotrophism
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
Composed of diglycerides
R group may be phosphate, sulfate, or sugar
Long chain branched hydrocarbon (not fatty acid)
Hydrocarbons may be C20 or C40
If C20, the membrane is a bilayer:
O
O
O
O
R
R
If C40, the membrane is a monolayer
O
O
O
O
R
R
In some species, the membrane is a mixture of both C20 and C40
diglycerides forming a mixed mono-/bi-layer
Thermus aquaticus
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
http://www.molgen.mpg.de/~ag_ribo/
ag_franceschi/franceschi-projects-30S.html
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Gram negative bacterium (not archaeon)
Thermophile isolated from
Yellowstone Hot Spring
Optimum temperature 85°C
Stability of macromolecules excellent
Enzymes for research or commercial use
Taq polymerase is the enzyme of PCR
(Polymerase Chain Reaction)
Lives near cyanobacteria which feed
Thermus
http://sci.agr.ca/crda/images/BACTERI1.JPG
Which of these metabolic pathways
is Thermus demonstrating?
• Photoautotrophism
• Photoheterotrophism
• Chemoautotrophism
√
• Chemoheterotrophism
Hint:
• Organic chemicals for energy
• Organic chemicals for carbon