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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

know mercury cycle maybe?

know mercury cycle maybe?