Homeostasis - metabolism
All of these nutritional modes are found among Bacteria!No other kingdom is as diverse in its metabolic pathways.
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
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http://www.plantmorphogenesis.bio.titech.ac.jp/images/Chloroplast%20Photo.jpg
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http://faculty.uca.edu/~johnc/Chloroplast_and_microbodies.jpg
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http://www.jgi.doe.gov/JGI_microbial/images/microbes2003/anava.jpg
Chemoautotrophs - N metabolism
• Cyanobacteria, Rhizobium - N2 fixation
H+ + ATP + N2 NH4+
• Nitrosomonas - nitrificationCO2 + NH4
+ NO2- + CH2O
• Pseudomonas - denitrificationCH2O + NO3
- N2 + CO2 + H2OWhich of these processes is demonstratingchemoautotrophism?
√
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http://soils.usda.gov/sqi/soil_quality/soil_biology/images/Nods_on_beans_LR.jpg
Photoheterotrophs - strange
• Rhodospirillum, Rhodomicrobium Light
C2H4O2- + H2O O2 + CH2O
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http://www.acadweb.wwu.edu/courses/envr429-rm/Robin/images/envr429/1_rhodospirillum_600x.jpg
Chemoheterotrophs - strange
• Escherichia coli and many others!
CH2O + O2 CO2 + H2O
Carbohydrate, etc. provides boththe energy source
andthe carbon source
What is another chemoheterotrophic organism?
Give the complete Latin binomial!
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http://www.up.ac.za/academic/electron/mito1.htm
Plant mitochondrion
cristae(mesosomes)
outer membraneinner membrane
Chemoheterotrophy• Aerobic Respiration
– Glycolysis carbohydrate to pyruvate– Citric Acid Cycle pyruvate to carbon dioxide– Electron Transport Oxidative Phosphorylation
CH2O + O2 CO2 + H2O• Anaerobic Fermentation
– Glycolysis to pyruvate– Fermentive step(s) to return NAD+ to glycolysis
C6H12O6 C3H3O3- C2H5OH + CO2
C6H12O6 C3H3O3- H3CCHOHCOO-
Notice how fermentation can produce gas or acids…These are just a few of the fermentive possibilities!