p2: nutrient cycles Flashcards

1
Q

nitrification process

A
  • via nitrifying bacteria
  • ammonia to nitrates via nitrites
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2
Q

denitrification process

A
  • by denitrifying bacteria
  • nitrates to oxygen gas
  • nitrates to nitrites
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3
Q

nitrogen fixation

A
  • nitrogen fixing bacteria
  • nitrogen gas to ammonia
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4
Q

decomposition process

A
  • saprobionts
  • ammonification
  • nitrogen containing compounds to ammonia
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5
Q

where is nitrogen found?

A
  • amino acids
  • proteins
  • nucleic acids: DNA/RNA
  • ADP
  • ATP
    -NADP
  • NAD/FAD
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6
Q

EXPLAIN what is meant by the term carbon sink

A
  • takes up CO2
    eg: coal, peat, trees
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7
Q

explain what is meant by global warming

A
  • increase of mean global temperature
  • CO2 is a greenhouse gas
  • reflects back long infrared waves in the atmosphere
  • increased greenhouse effect
  • leads to melting ice caps, flooding, climate change
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8
Q

describe the role of saprobionts in the nitrogen cycle

A
  • decompose proteins/DNA/RNA
  • releasing ammonia
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9
Q

describe how the action of microorganisms in the soil produces a source of nitrates for crop plants

A
  • DNA converted into ammonia
  • by saprobionts
  • ammonia into nitrates
  • by nitrifying bacteria
  • nitrogen gas to ammonia
  • by nitrogen fixing bacteria
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10
Q

explain how caron containing compounds present in pine leaves that fall from the trees are absorbed and used for growth by saprobionts/fungi that live in the soil

A
  • extracellular digestion
  • by secretion of enzymes
  • absorption of soluble products
  • synthesis of natural compunds
  • respiration provides energy for growth
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11
Q

nitrogen compounds in the plants are amde available after poughing in spring.
describe the role of microorganisms in this process.

A
  • proteins/AA broken down
  • deamination to release ammonium compounds
  • by saprobionts
  • conversion of nitates via nitrites
  • by nitrfying bacteria
  • nitrates absorped into roots by active transport
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12
Q

the scientist used units of micrograms/ grams for the concentration of ammonia in soil. suggest why, in this investigation, the scienitsists use this unit.

A
  • very ltitle ammonia in soil
  • avoids use of lots of decimal places
  • to allow comparisons
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13
Q

give 2 examples of biological molecules containing nitrogen that would be removed when a crop is harvested

A
  • amino acids
  • dna
    -rna
    0NAD
    -chlorophyll
    -ATP
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14
Q

plants absorb a number of other nutrients from the soil including phosphates. describe why phosphates are needed by a growing plant.

A
  • production of phospholipids
  • synthesis of ATP
  • production of ATP
  • production of RNA
  • production of NADP
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15
Q

describe how a lack of phosphates in the soil surrounding a plant can affect its growth

A
  • required to make ATP so less energy for growth
  • required to make nucleotides so less DNA
  • required to make RuBP so less CO2 fixed
  • required to make phospholipids for membranes
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16
Q

outline the advantages of having mycorrhizae growth near plants

A
  • helps plants defend themselves
  • helps plants take up nitrates and phosphates
17
Q

you are given samples of water from three different rivers. describe how you would obtain a quantitative measurement of their cloudiness

A
  • use of colorimeter
  • measure absorbance of light
  • zeroing colorimeter before use, same wavelength of light
18
Q

phosphorus cycle

A
  • RNA/DNA from dead organisms into phosphate ions
  • decomposed by saprobionts
  • phosphate ions found in water and remains (eg: bones)
  • Phosphate ions transported by streams, lakes and rivers
  • forms sedimentary rocks
  • erosion of rocks dissolves phosphate ions in oceans
  • become available for plants to absorb by plants via active transport to incorporate into biomass
19
Q

describe the process of eutrophication

A
  • nitrates and phosphates flushed into waterway
  • increased algal bloom
  • light blocked out
  • submerged aquatic plants unable to PS and die
  • increase in saprobionts so increases rate of aerobic respiration
  • saprobionts die as lack of oxygen
  • increase in anareobic microorganisms
  • production of toxins
20
Q

environmental impact of using fertilisers

A
  • reduced species diversity
  • replaces nitrates and phosphates
  • leaching (washed away in streams)
    -eutrophication
21
Q

mycorrhizae

A
  • fungi colonise root of host plant
  • thin hair like structures (mycelium) increase SA for fungi to fix nitrogen gas, absorb water, etc
  • plant gives fungus carbs formed in PS
22
Q

microorganisms make the carbon in polymers in a dead worm available to cells in a leaf. describe how.

A
  • microorganisms are saprobionts
  • secrete extracellular enzyme
  • absorb products iof digestion
  • RP produced CO2
  • CO2 taken into leaves
  • via stomata