Flashcards in Chapter 21 Deck (38):
1
Which CO2 is the most rapidly fixed
Atmosphere
2
Ways that CO2 is returned to the atmosphere
respiration, microbial decomposition (biggest return)
3
Photosynthesis Reaction
-CO2 +H2O --> (CH2O) + O2
4
Respiration Reaction
-(CH2O) + O2 --> CO2 + H2O
5
Two major end products of decompositio
-CH4 & CO2
6
How is methane effective in cold seeps/deep-sea ecosystems?
CH4 under high pressure low temperature becomes trapped
-nourishes anaerobic Arch. and Bac.
(CH4 endosymbionts)
7
Which two cycles are closely coupled?
-Carbon and NItrogen Cycle
8
KNOW CARBON CYCLE
KNOW CARBON CYCLE
9
KNOW THE COUPLED CYCLE
KNOW THE COUPLED CYCLE
10
What is methanogenesis?
central to C cycling in in anoxic environments
i)Reduce CO2 to CH4 with H2 as e- donor
ii)Some can reduce other substrates to CH4
11
How do methanogensis symbionts benefit the host?
by consuming H2 (generated from glucose fermentation)
12
What is another H2 consuming process besides methanogensis?
Acetogenesis (less favorable)
13
List the Major Nitrogen transformations
1. nitrification
2. denitrification
3. anammox
4. nitrogen fixation
14
how is nitrogen made
reduction of NO3- to NH3
15
what is responsible for 85% N loss
denitrification
16
KNOW THE NITROGEN CYCLE
KNOW THE NITROGEN CYCLE
17
What is nitrogen fixation?
the ability to use N2 (few prokaryotes have this ability)
18
What is denitrification?
i)Reduction of NO3 to gaseous N products
ii)Primary way N2 is produced biologically
19
Two ways NH3 can be made from N
1. N-fixation
2. ammonification
20
what changes NH3 to N2 gas
Anammox-anoxic oxidation
21
KNOW NITRATE REDUCTION FLOW CHART
KNOW NITRATE REDUCTION FLOW CHART
22
Focus a lot of nitrate reduction and its various stuff
Focus a lot of nitrate reduction and its various stuff
23
Which cycle has to most significant oxidation states
Sulfur (-2, 0, 6)
24
Major sulfur reservoirs
1. sediments and rocks
2. ocean (as sulfate SO4-2)
25
KNOW SULFUR CYCLE
KNOW SULFUR CYCLE
26
What is the most abundant organic sulfur compound
Dimethyl Sulfide (DMS)
27
What can sulfur-oxidizing chemolithiotrophs oxidize in oxic/anoxic environment?
HS- (oxic)
S^0 (anoxic)
28
one of the Most abundant element and its form?
Iron
Fe2+ and Fe3+ in environemnt
Fe0 in human and earths core
29
KNOW IRON CYCLE
KNOW IRON CYCLE
30
Which organism oxidizes Fe2+
acidophilic chemolithiotrophs (i.e. Acidithiobacillus)
31
What form of iron and Mn is soluble and insoluble
Insoluble: Fe+3 Mn+4
Soluble: Fe+2 Mn+2
32
how does the phosphate cycle cycle?
organisms -> water -> soil
33
why is the calcium cycle important and where does it come from?
reservoirs are from rocks and oceans
marine phototrophic eukaryotic microbes:
i)Use Ca2+ to form exoskeleton
ii)Coccolithophores & foraminifera
34
why is the silicon cycle important?
Build frustules
1. External cell skeletons
a. Not to be confused w/ cytoskeleton
b. Made of SiO2
(opal)
-Uptake H4SiO4
(silicic acid)
2. Analogous to cell wall, shell, or husk
35
what is Hg0 photochemically oxidized to
Hg+2 (most Hg enters aquatic environments as Hg+2)
36
What two forms of mercury can microbes create?
•Microbes can form
-Methylmercury (CH3Hg+)
i)Extremely soluble & toxic compound
-Dimethylmercury (CH3HgCH3)
i)Toxic & highly volatile, can be inhaled
37
Two ways toxic Hg can be converted
•Toxic Hg can be converted to less toxic forms
-Sulfate-reducing bacteria
i)H2S + Hg2+ → HgS, low solubility
-Methanogens
i)CH3Hg+ converted to CH4 and Hg0
1. Hg0
is less toxic…but still toxic
38