p2: nutrient cycles Flashcards
nitrification process
- via nitrifying bacteria
- ammonia to nitrates via nitrites
denitrification process
- by denitrifying bacteria
- nitrates to oxygen gas
- nitrates to nitrites
nitrogen fixation
- nitrogen fixing bacteria
- nitrogen gas to ammonia
decomposition process
- saprobionts
- ammonification
- nitrogen containing compounds to ammonia
where is nitrogen found?
- amino acids
- proteins
- nucleic acids: DNA/RNA
- ADP
- ATP
-NADP - NAD/FAD
EXPLAIN what is meant by the term carbon sink
- takes up CO2
eg: coal, peat, trees
explain what is meant by global warming
- 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
describe the role of saprobionts in the nitrogen cycle
- decompose proteins/DNA/RNA
- releasing ammonia
describe how the action of microorganisms in the soil produces a source of nitrates for crop plants
- DNA converted into ammonia
- by saprobionts
- ammonia into nitrates
- by nitrifying bacteria
- nitrogen gas to ammonia
- by nitrogen fixing bacteria
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
- extracellular digestion
- by secretion of enzymes
- absorption of soluble products
- synthesis of natural compunds
- respiration provides energy for growth
nitrogen compounds in the plants are amde available after poughing in spring.
describe the role of microorganisms in this process.
- 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
the scientist used units of micrograms/ grams for the concentration of ammonia in soil. suggest why, in this investigation, the scienitsists use this unit.
- very ltitle ammonia in soil
- avoids use of lots of decimal places
- to allow comparisons
give 2 examples of biological molecules containing nitrogen that would be removed when a crop is harvested
- amino acids
- dna
-rna
0NAD
-chlorophyll
-ATP
plants absorb a number of other nutrients from the soil including phosphates. describe why phosphates are needed by a growing plant.
- production of phospholipids
- synthesis of ATP
- production of ATP
- production of RNA
- production of NADP
describe how a lack of phosphates in the soil surrounding a plant can affect its growth
- 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
outline the advantages of having mycorrhizae growth near plants
- helps plants defend themselves
- helps plants take up nitrates and phosphates
you are given samples of water from three different rivers. describe how you would obtain a quantitative measurement of their cloudiness
- use of colorimeter
- measure absorbance of light
- zeroing colorimeter before use, same wavelength of light
phosphorus cycle
- 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
describe the process of eutrophication
- 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
environmental impact of using fertilisers
- reduced species diversity
- replaces nitrates and phosphates
- leaching (washed away in streams)
-eutrophication
mycorrhizae
- 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
microorganisms make the carbon in polymers in a dead worm available to cells in a leaf. describe how.
- microorganisms are saprobionts
- secrete extracellular enzyme
- absorb products iof digestion
- RP produced CO2
- CO2 taken into leaves
- via stomata
