LIFESCI 1 Lecture Notes - Lecture 12: Sulfur Cycle, Partial Oxidation, Chemosynthesis
Document Summary
Aerobic vs. anaerobic: where oxygen is limited, other electron donors can be used for photosynthesis and other electron acceptors can be used for respiration. Only bacteria and archaea can use these alternatives for anaerobic photosynthesis/respiration: microbial mats = carpets of densely packed communities of bacteria and archaea. Bacteria and archaea thrive where animals and seaweed can"t grow. Dominated by cyanobacteria (photosynthetic bacteria that use water as their electron donor and releases oxygen) At mat surface, cyanobacteria and heterotrophic bacteria respire aerobically. Uses oxygen to oxidize organic molecules to co2. Prokaryotic microorganisms carry out biological carbon cycle at mat surface. Carbon dioxide continues to be reduced to carbohydrates under mat. Don"t gain electrons from water, so oxygen gas is not made: bacteriorchlorophyll = light harvesting pigment in plants, algae, and cyanobacteria. Absorbs similar light waves as chlorophyll; is how photosynthetic bacteria (anoxygenic) do photosynthesis. Absorbs uv and infrared wavelengths of light, outside of visible spectrum.
