Microbial Ecology [1] Flashcards
Recall that the bacteria in the chapter openers produced electrically-conductive structures that function like “living electrical cables,” allowing the organism to conduct electrons along the length of its filament. Under what conditions would production of electrically conductive structures be favored?
Choose all that apply.
A The organism oxidizes H2 and uses iron oxides as the electron acceptor.
B The organism uses an electron donor and an electron acceptor that are physically separated.
C The organism is a chemolithotroph that oxidizes H2 and reduces CO2 to form CH4.
D The organism is photosynthetic and uses H2O as the electron donor.
E The organism ferments glucose and uses it both for the carbon and the energy source.
A
B
Anammox:
The use of nitrate (NO3-) as an electron acceptor with formation of one gaseous end product (N2)
makes gas
Nitrification:
The aerobic process that uses ammonium (NH4+) as an energy source
produces nitrite
Denitrification:
The use of nitrate (NO3-) as an electron acceptor with formation of multiple gaseous end products (N2, N2O, or NO)
removes nitrite
Nitrogen Fixation:
An assimilatory process in which N2 is converted to ammonia (NH3) for incorporation into organic nitrogen-containing
Ammonification:
Many organisms, both prokaryotic and eukaryotic, release ammonium (NH4+) from degradation of nitrogen-containing organic materials
release of N from an organic source as ammonia (ammonia produced)
Soluble Fe2+ and Mn2+ to insoluble, and back to soluble
soluble –> diffuses to oxic region –> solubles oxidized –> insoluble metal oxides and hydroxides precipitate –> oxidized metals in sediment –> metals reduced by bacterium (as e- acceptors) –> soluble
Carbon dioxide and methane are potent greenhouse gases, with methane having 20 times more warming potential in the atmosphere than CO2. As global warming progresses, there is the real possibility that increased temperatures on land and in the oceans will lead to a positive feedback effect leading to accelerated warming. From the carbon reservoirs listed below with their percentage of the total carbon on Earth, what would be the most dangerous potential source of C that could be released to potentiate further warming?
A fossil fuels (0.006%)
B methane hydrates (0.014%)
C oceans and terrestrial biosphere (0.053%)
D rocks and sediments (99.5%)
B
Many nutrient cycles are coupled and changes in one cycle will affect another. This means that a change in the amount of carbon dioxide fixed is intimately affected by the amount of \_\_\_\_\_\_\_\_\_\_. A nitrogen available in an ecosystem B methane available in an ecosystem C oxygen available in an ecosystem D hydrogen available in an ecosystem
A
As nutrients cycle in the biosphere, \_\_\_\_\_\_\_\_\_\_ can participate in every transformation from one chemical form of a nutrient to another. A animals B plants C prokaryotes D fungi
C
Decomposition of organic carbon ultimately results in the formation of __________.
A CO2 in aerobic environments and CH4 in anoxic environments
B CH4 in aerobic environments and CO2 in anoxic environments
C CO2 in aerobic environments and CO2 plus CH4 in anoxic environments
D CO2 plus CH4 in aerobic environments and CH4 in anoxic environments
C
Which of the following is/are NOT a degradation product of organic material? A oxygen B carbon dioxide C methane D carbon dioxide, methane, and oxygen
A
Which organisms form the foundation of the carbon cycle? A anaerobic chemolithotrophs B phototrophs C chemoorganotrophs D chemoheterotrophs
B
Frozen methane molecules are called A methane anhydrates. B methane hydrates. C anoxic methane. D anhydrous methane.
B
What is a characteristic of a deep sea marine cold seep/vent? A luminous B acidic C rich in methane D low pressure
C
NO OXYGEN (SO METHOGENESIS FLOURISHES)
What is the largest carbon sink on Earth? A terrestrial biosphere B fossil fuels C rocks and sediments D aquatic biosphere
C
