Lecture 4 Whyte Flashcards
The _________________ indicates the type of cell wall a bacterial cell possesses
Gram stain
Gram positive are _________ and gram negative are ___________
purple
pink
Most of the characterized bacterial phyla, including many involved in biodegradation )ex: Pseudomonas) are gram ________________
negative
Gram negative cells have a _______ cell wall in the periplasmic space between the cytoplasmic and outer membranes
thin
Gram-positive cell walls are found in the ________________ and the _______________ (including Bacillus, Rhodococcus, etc)
- Firmicutes
- Actinobacteria
Gram positive cells have a ________ cell wall outside the cytoplasmic membrane and do not have an ____________
thick
outer membrane
T or F: The cell walls and membranes of Archaea are completely different from those of Bacteria or Eucarya
T
Describe the 4 steps of a gram stain:
- application of crystal violet
- application of iodine (mordant)
- application of alcohol (decolorization)
- application of safranin (counterstain)
T or F: plants fix CO2 to organic compounds
T
T or F: Since the early 1900s, it has been recognized that organic matter is decomposed into small inorganic molecules, which are immobilized again by growing cells, cucled
T
Microbes play a great role in maintaining the dynamic equilibrium between the organic matter reservoir and the ________________
mineralized reservoir
T or F: Greenhouse gases cause climate change because they trap heat in our atmosphere (ex: CO2, CH4, N2O)
T
Microbes throughout the biosphere recycle: _______, ________, ___________ and other elements essential for all life
- carbon
- nitrogen
- sulfur
T or F: Today all of these geochemical cycles are altered profoundly by human activity
T
As _________ is the most important element in the biosphere since it is the main constituent of cellular polymers (and organic pollutants)
carbon
CO2 may be fixed into organic matter either under ____________ conditions by oxygenic photosynthetic organisms (ie; cyanobacteria, algae, plants) and some chemolithoautotrophic bacteria (ie: nitrifying, sulfur-oxidizing bacteria) or under anaerobic conditions by anoxygenic photosynthetic bacteria (ie: rhodospirillum, chlorobium)
aerobic
Organic matter is oxidized back to CO2 via aerobic respiration or ________________________
anaerobic respiration and fermentation
In soil or sediment, carbon may be in the organic matter which may be active (__________) or inactive (______________-)
living biomass
dead biomass
The mineral reservoir of carbon is ___________ or dissolved CO2 and calcareous _______ and _______ (calcium carbonate)
atmospheric
rocks and corals
Some of the organic matter as well as CO2 may be converted to CH4 by diverse groups of Archaea called __________
methanogens
CH4 can be oxidized to CO2 by a specialized group of bacteria called the _______________
methanotrophs
Methylosinus and Methylococcus are examples od:
methanotrophs
T or F: Artic regions are the ones that are warming up the fastest
T
Methanotrophs possess a key enzyme that oxidizes CH4 to methanol: ________________(MMO), sometimes present on complex membrane structures
methane monooxygenase
nitrifying bacteria that oxidize _________ to nitrite (see N cycle) have a similar enzyme called ammonium monooxygenase (AMO)
NH4
The MMO system is very much studies since it can oxidize ______________________(TCE) in addition the CH4
trichloroethylene
_____________ can be useful to treat natural systems contaminated with TCE either in reactors or in natural systems
methanotrophs
What is the PPM concentration of CO2 in our atmosphere today?
Around 417 ppm
The many oxidation states of S in various compounds means that reduced sulfur compounds are good energy sources while oxidized forms of S can be used as ___________________ for anaerobic respiration
electron acceptors
sulfur is also an important element in the cell because of:
sulfur-containing amino acids such as methionine and cysteine
Bacteria can degrade pollutants via anaerobic respiration is sulfate is abundant for use as terminal electron acceptor, process called:
dissmilatory sulfate reduction
__________________ is a well know example for sulfate reducing bacteria, utilize sulfate as terminal electron acceptor, use H2 and/or organic carbon as energy source
Desulfovibrio
desulfo = sulfate reduction
Prokaryotes have an extraordinary ________________
metabolic diversity and capacity
Microbial bioenergetics and biogeochemical cycling are intricately ________
linked
____ is an important element in cells (ir for proteins and nucleic acids)
Nitrogen
T or F: growth of organisms (plants or pollutant-degrading bacteria) is often limited by nitrogen availability
T
Bacteria can degrade pollutants via anaerobic respiration if nitrate is abundant for use as terminal electron acceptor, this process is called:
dissimilatory nitrate reduction
T or F: In bioremediation, addition of N-fertilizer (ammonium nitrate) often stimulates mineralization of organic matter by decreasing the C/N ratio
T
While the atmosphere is 79% N2 gas, only a small proportion of ________ and _______ (but no eucaryal) species, the diazotrophs, can fix n2
bacterial and archaeal
N2-fixing bacteria (ex: azobacter) possess the enzyme ____________ that can reduce N2 to NH4+
NITROGENASE
T or F: Most microbes and plants can assimilate NH4+
T
NH4+ can be oxidized to NO2- and NO3- by bacterial ______________ under aerobic conditions
nitrfication
____________ oxidize NH4+ to NO2- it possesses the enzyme ammonium monooxygenase (amo enzyme)
Nitrosomonas sp.
_____________ oxidize NO2- TO NO3-
Nitrobacter
NO3- may be assimilated by microbes and plants into organic matter or be reduced by bacteria to N2 via ________
denitrification
