Biology: life study of What is Life? Cellular Structure: the unit of life, one or many Growth: cell...

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!

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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



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



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



http://epr2004.sr.unh.edu/images/hires/hireswtsmoker.jpg



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



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?





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







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



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



http://sci.agr.ca/crda/images/BACTERI1.JPG





Which of these metabolic pathwaysis Thermus demonstrating?

√Hint:

• Organic chemicals for energy

• Organic chemicals for carbon

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