Microbes and Energy Flashcards
What is the “unseen majority”?
Most organisms cannot be or have not been isolated in pure culture
Identification now done using genetic fingerprints
The uncultured microbial world is far greater than the cultured world
How is a population formed?
Populations are formed when individual microbial cells of a species proliferate to form a population
How is a community formed?
Populations interact/communicate to form a community
What is microbial ecology ?
The study of the interrelationships among microorganisms and their environment
How is reduction - oxidation used in bacteria?
For every action (e.g. oxidation) there is an equal and opposite reaction (e.g. reduction)
A redox reaction shuttled through NADH/NADPH
What is a chemoautotroph?
Energy source : chemical compounds
Carbon source : carbon dioxide
Example : Hydrogen, sulfur and nitrifying bacteria
What is a chemoheterotroph?
Energy source : Chemical compound
Carbon source : Organic compound
Example : Aerobic respiration, anaerobic respiration, fermentation
What is a photoautotroph?
Energy source : Light
Carbon source : Carbon dioxide
Example : Plants, algae, cynobacteria, green sulfur bacteria and purple sulfur bacteria
What is a photoheterotroph?
Energy source : Light
Carbon source : Organic compound
Example : green nonsulfur bacteria and purple nonsulfur bacteria
What are autotrophs?
Primary producers
Fix CO2
Self sufficient, do not require carbon
What are heterotrophs?
Decomposes
Need fixed carbon, cannot use CO2 directly
Dependent on primary producers
What are chemotrophs?
Use chemical energy from either C compounds (organic) or non-c compound (inorganic)
Organic = glucose
Inorganic = H2S
What are phototrophs?
Use solar energy
Energy from sunlight
How can so many different microbes share the same metabolisms?
Light is a common resource
Avoid competition by tuning their antenna to different wavelength
Why do we care about redox and metabolism?
Exploitation of different redox potential drives organisation of global microbial communities
Different redox gradients select for different microbes
What are cable bacteria?
Oxygen dependent organisms living in anoxic environments
Create cables to shuttle electrons from anoxic into oxic zone, allows them to breathe oxygen while living in anoxic conditions
