Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbes and You > Nutrient Cycles L14 > Flashcards

Nutrient Cycles L14 Flashcards

1
Q

what is the nutrient cycle like

A

not a closed system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

where does nutrient cycling occur

A

Nutrient cycling occurs at global level
through geological processes, such as,
atmospheric circulation, erosion and
weathering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is geochemical cycles

A

atoms of earth are in flux and occur in different places at different times

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is a biogeochemical cycle

A

path atoms take between biotic (biosphere) and abiotic (lithosphere, atmosphere, and hydrosphere) world, and back again

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what do biogeochemical cycles involve

A

natural processes that recycle nutrients in various chemical forms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the biogeochemical cycle effect

A

are usually localized in effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what do plant do to calcium in bones

A

calcium in your bones are mobilized by plants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what helps plants mobilise calcium

A

microbes from minerals in rocks that were once formed in the sea by sedimentation from calcite shells of microscopic marine creatures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the in which all the chemistry of life takes place

A

water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is a source of hydrogen in photolysis

A

water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what splits water

A

plant cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what reconstitutes water

A

biota

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what effect water residence times in various reservoirs

A

abiotic factors, such as increased/decreased solar energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

reservoir examples

A

oceans

atmospheres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

of the 50-70 elements found in living things how many are cycled

A

more than thirty are cycled through environment by biogeochemical cycles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the six most important biogeochemical cycles

A 
carbon
hydrogen
oxygen
nitrogen 
phosphorus 
sulphur
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

where do organisms get nutrients and energy from

A

Organisms derive nutrients and energy from their habitat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are the energy pyramid feeding relationships

A

producers
consumers
decomposers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are producers

A

provide fundamental energy source; only organisms that can produce organic compounds by assimilating inorganic carbon from atmosphere;
Photosynthetic organisms
termed autotrophs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are consumers

A

feed on other living
organisms and obtain energy from
breaking chemical bonds; primary,
secondary, tertiary…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what are decomposers

A 
primarily 
microbes, break down and absorb 
organic matter of dead organisms; recycle organic matter 
into inorganic minerals and gases, 
mineralise nutrients
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are terrestrial habitats made of

A

organic compartment consists of living organisms and their detritus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is in the available nutrient compartment

A

available-nutrient compartment consists of nutrients held to surface of soil particles or in solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what does the third compartment consist of

A

nutrients held
in soils or rocks that are unavailable directly to living
organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what does the fourth compartment consist of

A

air which can be found in atmosphere or in ground

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what is the main path for nutrients in soil

A

from the soil through the roots of producers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what is soil like

A

a dynamic, complex ecosystem with a vast array of microbes, animals, and plants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what are lichens

A

symbiotic associations between a fungus and a cyanobacterium or green algae produce acids that releases
minerals from rocks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what is humus

A

rich moist layer of soil
containing plant and animal debris
being decomposed by microbes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what is rhizosphere

A

zone of soil around plant roots, fungi and protozoa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what is mycorrhizae

A

symbiotic organs formed between fungi and certain plant roots

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what are aquatic habitats like

A

Often stratified, limited mixing of layers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what mixes aquatic habitats

A

Winds mix waters within epilimnion during summer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what isolates mixing to the surface of water

A

thermocline isolates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

when does turnover in aquatic habitats occur

A

winter months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what does turnover of aquatic habitats cause

A

breakdown of thermocline

allowing mixing and nutrient flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what is the primary reservoir

A

atmosphere acts for carbon dioxide (CO2), oxygen (O2) and water (H2O)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

how can inorganic compounds be exchanged with biota

A

inorganic compounds can be exchanged directly with biota through processes of photosynthesis and respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what is the most abundant gas in atmosphere

A

nitrogen 78%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

where carbon tied up

A

most in sedimentary rocks but the portion that circulates is what sustains life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

how much carbon is there estimated to be

A

around 40,000 gigatons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

where is most of the carbon

A

93% in ocean

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

how is carbon recycled

A

through ecosystems via photosynthesis, respiration, and fermentation of organic molecules, limestone decomposition and methane production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

how long does the carbon cycle for atmosphere take

A

3 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

how long does the carbon cycle for soil take

A

25-30 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

how long does the carbon cycle for oceans take

A

1,500 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

what dominates terrestrial ecosystems photosynthesis

A

plants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

what dominates aquatic ecosystem

A

phototrophic

microbes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

what are the basic elements of life

A

Carbon, hydrogen and oxygen

makes up 98% od plant biomass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

how do CO2 and O2 enter biota

A

atmosphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

example of producers

A

photosynthetic autotrophs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

what do photosynthetic autotrophs do

A

convert CO2 and H2O into carbohydrates (CH2O compounds) splitting water and releasing O2 in process

53
Q

what is light dependent

A

photons are absorbed by chlorophyll, carotenoids, or phycobilin pigments

54
Q

how is water split

A

photolysis

55
Q

what happens in photolysis

A

releasing O2 gas and provide electrons to drive photophosphorylation

56
Q

what is released from light dependent reaction

A

released light energy used to synthesize ATP and NADPH

57
Q

what happens in light independent reaction

A

Calvin cycle – uses ATP to fix CO2 to ribulose-1,5-bisphosphate and convert this to glucose

58
Q

what reactions are part of the redox cycle

A

photosynthesis

respiration

59
Q

what happens in photosynthesis

A

CO2 + H2O –> (CH2O) + O2

60
Q

what happens in respiration

A

(CH2O) + O2 –> CO2 + H2O

61
Q

what are the two major end products of decomposition

A

CH4 and CO2

62
Q

what do methanogens do

A

reduce CO2 and give off methane (CH4)

63
Q

how does carbon enter the atmosphere

A

CO2 by respiration, fermentation, decomposition of marine deposits, and burning fossil fuels

64
Q

what is the largest carbon dioxide source

A

microbial decomposition

65
Q

what is methanogenesis important in

A

central to carbon cycling in anoxic environments

66
Q

what do most methanogens do

A

reduce CO2 to CH4 with H2 as an electron donor; some can reduce other substrates to CH4 (e.g., acetate)

67
Q

what do methanogens team up with

A

partners (syntrophs)

68
Q

what do syntrophs supply to methanogens

A

supply them with necessary substrates

gut microbiota, termites, ruminants and humans

69
Q

what does acetogenesis process do

A

H2 -consuming process

competing with methanogenesis in some environments

70
Q

where does acetogensis occur

A

termite hindgut

71
Q

which is more energetically favourable

  • methanogenesis
  • acetogenesis
A

methanogenesis energetically more favourable

72
Q

what can acetogens ferment

A

ferment glucose

methoxylated aromatic compounds

73
Q

what group are methane hydrates in

A

clathrates – one molecule forms crystal-like cage structure, encloses another type of molecule, in this case water - as ice - surrounds methane

74
Q

how is nitrogen used

A

nitrogen fixing bacteria to convert N2 into NH3 (NH4+)

75
Q

where are nitrogen oxides from

A

combustion sources that use fossil fuels

76
Q

what fixes nitrogen

A

Substantial amounts are ‘fixed’ by artificial means (Haber–Bosch process)

77
Q

what is the largest source of soil nitrogen in natural ecosystems

A

nitrogen fixation

78
Q

what things can convert nitrogen to ammonia and ammonium

A

Free-living soil bacteria and cyanobacteria

79
Q

what are symbiotic bacteria

A

in nodules of legumes and certain other plants can also fix nitrogen

80
Q

what is needed for bacterial species to convert nitrites, nitrates and nitrous oxides into molecular nitrogen

A

under anaerobic conditions

use nitrate as an alternative electron acceptor

81
Q

what is a negative impact on nitrogen cycle

A

waterlogged (anoxic) soils removes ‘fixed’ nitrogen

82
Q

what is a positive impact on nitrogen cycle

A

sewage effluent removing fixed nitrogen as volatile N2 to minimise algal blooms

83
Q

is nitrate soluble

A

nitrate washed away

very soluble

84
Q

what happens in nitrification

A

NH4+ –> NO2- –> NO3-
overall: NH4+ –> NO3-
ammonium to nitrate

85
Q

what happens in dentrification

A

NO3- –> N2

nitrate to nitrogen gas

86
Q

what happens in nitrogen fixation

A

N2 + 8H –> NH3 + H2

nitrogen gas to ammonia

87
Q

examples of aerobic nitrogen fixation

A

cyanobacteria

88
Q

examples of anaerobic nitrogen fixation

A

clostridium

89
Q

examples of symbiotic nitrogen fixation

A

rhizobium

90
Q

what happens in ammonification

A

organic N –> NH4+

form ammonium

91
Q

what happens in anammox

A

NO2- + NH3 –> 2N2

nitrite + ammonia –> nitrogen gas

92
Q

what is added to supplement the nitrogen lost through plant harvest

A

Various forms of commercial fertiliser are added to agricultural fields

93
Q

what prevents nitrogen loss

A

Will add nitrogen oxidase inhibitors – prevent nitrogen loss as gas by stopping reaction NO3- to NO2- prevent soil bacteria undergo this process, maintain as ammonia as plants can use this

94
Q

what is practiced to supplement spoil nitrogen

A

Crop rotation with legumes such as soybeans or alfalfa

95
Q

what can nitrogen run off cause

A

result in harmful ‘blooms’ of aquatic microorganisms

96
Q

what does algal bloom form

A

Dinoflagellate -Alexandrium fundyense

Diatom - Pseudo-nitzschia

97
Q

what is phosphorus in environment

A

phosphate ion (POv4^3-), is an essential element of life

98
Q

how does phosphorus cycle through atmosphere

A

does not cycle through atmosphere, enters producers through soil, cycled locally through producers, consumers and decomposers
over very long time periods (geological time) phosphorus
follows a sedimentary cycle

99
Q

what causes phosphorus loss

A

small local losses by leaching

100
Q

how are small phosphorus losses balanced

A

balanced by gains from the weathering of rocks

101
Q

where does sulphur originate from

A

rocks, oceans, lakes and swamps

102
Q

where is the bulk of sulphur

A

occurs in sediments and rocks as sulphate and sulphide minerals

103
Q

what is the most significant reservoir for sulphur in biosphere

A

oceans

104
Q

what is sulphur in atmosphere

A

exists in elemental form and as hydrogen sulphide gas (extremely toxic to us), sulphates (SO42-) and thiosulphates (S2O32−)

105
Q

what is hydrogen sulphide

A

volatile sulphur gas produced by bacteria via sulphate reduction or emitted from geochemical sources

106
Q

what is the problem with sulphur

A

toxic to many plants and animals and reacts with numerous metals

107
Q

what can sulphur-oxidizing chemolithotrophs do

A

oxidize sulfide and elemental sulphur at oxic/anoxic interfaces

108
Q

what can plants assimilate

A

sulphate ion SO24-

109
Q

what can animals assimilate

A

sulphate ion

SO24-

110
Q

can animals assimilate sulphur ion SO42-

A

require an organic source – amino acids: cysteine, and methionine

111
Q

bacteria effect on sulphurous compounds

A

Bacteria convert environmental sulphurous compounds into useful substrates

112
Q

what can metabolise organic sulphur

A

microorganisms

113
Q

what is the most abundant organic sulphur compound in nature

A

dimethyl sulphide (DMS)

114
Q

where is DMS primarily produced

A

Produced primarily in marine environments as a degradation product of dimethylsulphoniopropionate (an algal osmolyte)

115
Q

how can DMS be transformed

A

via a number of microbial processes

116
Q

what happens in sulfide/sulfur oxidation

A

H2S –> S^0 –> SO42-
hydrogen sulphide
sulfur oxide
sulphate

117
Q

example of aerobic sulfide/sulfur oxidation

A

sulfur chemolithotrophs

118
Q

what happens in sulfate reduction

A

SO42- –> H2S

sulfate to hydrogen sulphide

119
Q

example of anaerobic sulfide/sulfur oxidation

A

purple and green phototrophs

some chemolithotrophs

120
Q

example of anaerobic sulfate reduction

A

archaea

121
Q

what happens in anaerobic sulfur reduction

A

S^0 –>H2S

sulfur oxide to hydrogen sulphide

122
Q

example of anaerobic sulfur reduction

A

many hyperthermophilic archaea

123
Q

what happens in sulfur disproportionation

A

S2O32- –> H2S + SO42-

thiosulphate to hydrogen sulphide and sulphate

124
Q

example of sulphur disproportionation

A

desulfovibrio

125
Q

what happens in organic sulfur compound oxidation or reduction

A

CH3SH –> CO2 + H2S

DMSO –> DMS

126
Q

example of organic sulfur compound oxidation or reduction

A

many organisms can do this

127
Q

what happens in desulfurylation

A

organic S –> H2S

128
Q

example of desulfurylation

A

many organisms can do this

Microbes and You (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions