Lecture 4 Whyte

Question 1

The _________________ indicates the type of cell wall a bacterial cell possesses

Answer 1

Gram stain

Question 2

Gram positive are _________ and gram negative are ___________

Answer 2

purple

pink

Question 3

Most of the characterized bacterial phyla, including many involved in biodegradation )ex: Pseudomonas) are gram ________________

Answer 3

negative

Question 4

Gram negative cells have a _______ cell wall in the periplasmic space between the cytoplasmic and outer membranes

Answer 4

thin

Question 5

Gram-positive cell walls are found in the ________________ and the _______________ (including Bacillus, Rhodococcus, etc)

Answer 5

• Firmicutes

- Actinobacteria

Question 6

Gram positive cells have a ________ cell wall outside the cytoplasmic membrane and do not have an ____________

Answer 6

thick

outer membrane

Question 7

T or F: The cell walls and membranes of Archaea are completely different from those of Bacteria or Eucarya

Answer 7

T

Question 8

Describe the 4 steps of a gram stain:

Answer 8

• application of crystal violet
• application of iodine (mordant)
• application of alcohol (decolorization)
• application of safranin (counterstain)

Question 9

T or F: plants fix CO2 to organic compounds

Answer 9

T

Question 10

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

Answer 10

T

Question 11

Microbes play a great role in maintaining the dynamic equilibrium between the organic matter reservoir and the ________________

Answer 11

mineralized reservoir

Question 12

T or F: Greenhouse gases cause climate change because they trap heat in our atmosphere (ex: CO2, CH4, N2O)

Answer 12

T

Question 13

Microbes throughout the biosphere recycle: _______, ________, ___________ and other elements essential for all life

Answer 13

• carbon
• nitrogen
• sulfur

Question 14

T or F: Today all of these geochemical cycles are altered profoundly by human activity

Answer 14

T

Question 15

As _________ is the most important element in the biosphere since it is the main constituent of cellular polymers (and organic pollutants)

Answer 15

carbon

Question 16

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)

Answer 16

aerobic

Question 17

Organic matter is oxidized back to CO2 via aerobic respiration or ________________________

Answer 17

anaerobic respiration and fermentation

Question 18

In soil or sediment, carbon may be in the organic matter which may be active (__________) or inactive (______________-)

Answer 18

living biomass

dead biomass

Question 19

The mineral reservoir of carbon is ___________ or dissolved CO2 and calcareous _______ and _______ (calcium carbonate)

Answer 19

atmospheric

rocks and corals

Question 20

Some of the organic matter as well as CO2 may be converted to CH4 by diverse groups of Archaea called __________

Answer 20

methanogens

Question 21

CH4 can be oxidized to CO2 by a specialized group of bacteria called the _______________

Answer 21

methanotrophs

Question 22

Methylosinus and Methylococcus are examples od:

Answer 22

methanotrophs

Question 23

T or F: Artic regions are the ones that are warming up the fastest

Answer 23

T

Question 24

Methanotrophs possess a key enzyme that oxidizes CH4 to methanol: ________________(MMO), sometimes present on complex membrane structures

Answer 24

methane monooxygenase

Question 25

nitrifying bacteria that oxidize _________ to nitrite (see N cycle) have a similar enzyme called ammonium monooxygenase (AMO)

Answer 25

NH4

Question 26

The MMO system is very much studies since it can oxidize ______________________(TCE) in addition the CH4

Answer 26

trichloroethylene

Question 27

_____________ can be useful to treat natural systems contaminated with TCE either in reactors or in natural systems

Answer 27

methanotrophs

Question 28

What is the PPM concentration of CO2 in our atmosphere today?

Answer 28

Around 417 ppm

Question 29

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

Answer 29

electron acceptors

Question 30

sulfur is also an important element in the cell because of:

Answer 30

sulfur-containing amino acids such as methionine and cysteine

Question 31

Bacteria can degrade pollutants via anaerobic respiration is sulfate is abundant for use as terminal electron acceptor, process called:

Answer 31

dissmilatory sulfate reduction

Question 32

__________________ is a well know example for sulfate reducing bacteria, utilize sulfate as terminal electron acceptor, use H2 and/or organic carbon as energy source

Answer 32

Desulfovibrio | desulfo = sulfate reduction

Question 33

Prokaryotes have an extraordinary ________________

Answer 33

metabolic diversity and capacity

Question 34

Microbial bioenergetics and biogeochemical cycling are intricately ________

Answer 34

linked

Question 35

____ is an important element in cells (ir for proteins and nucleic acids)

Answer 35

Nitrogen

Question 36

T or F: growth of organisms (plants or pollutant-degrading bacteria) is often limited by nitrogen availability

Answer 36

T

Question 37

Bacteria can degrade pollutants via anaerobic respiration if nitrate is abundant for use as terminal electron acceptor, this process is called:

Answer 37

dissimilatory nitrate reduction

Question 38

T or F: In bioremediation, addition of N-fertilizer (ammonium nitrate) often stimulates mineralization of organic matter by decreasing the C/N ratio

Answer 38

T

Question 39

While the atmosphere is 79% N2 gas, only a small proportion of ________ and _______ (but no eucaryal) species, the diazotrophs, can fix n2

Answer 39

bacterial and archaeal

Question 40

N2-fixing bacteria (ex: azobacter) possess the enzyme ____________ that can reduce N2 to NH4+

Answer 40

NITROGENASE

Question 41

T or F: Most microbes and plants can assimilate NH4+

Answer 41

T

Question 42

NH4+ can be oxidized to NO2- and NO3- by bacterial ______________ under aerobic conditions

Answer 42

nitrfication

Question 43

____________ oxidize NH4+ to NO2- it possesses the enzyme ammonium monooxygenase (amo enzyme)

Answer 43

Nitrosomonas sp.

Question 44

_____________ oxidize NO2- TO NO3-

Answer 44

Nitrobacter

Question 45

NO3- may be assimilated by microbes and plants into organic matter or be reduced by bacteria to N2 via ________

Answer 45

denitrification