6.3.1 (c) Nitrogen Cycle Flashcards
organic compunds in living organisms which contain nitrogen?
- amino acids
- nucleic acids
what is nitrification?
conversion of ammonia into nitrites and then nitrates
bacteria needed for ammonia to nitrite?
nitrosomonas
bacteria needed for nitrite to nitrate?
nitrobacter
how is nitrogen taken up in a plant?
nitrate ions are very soluble so can be easily taken up by plants
what is ammonification?
decomposers convert nitrogen containing molecules into ammonium in the soil
ammonification equation?
NO3- to Ammonia
difference between decomposers and detritivores?
detritivores break down decaying material into smaller pieces to give a larger surface area
decomposers feed on decaying material (therefore saprophytes)
what is denitrification?
conversion of nitrates to nitrogen gas
bacteria needed for denitrification?
pseudonomas
bacteria uses nitrates for respiration and produce nitrogen gas
conditions needed for denitrification?
anaerobic conditions (waterlogged soil)
conditions of soil in nitrogen cycle?
needs space for oxygen to allow for aerobic respiration in bacteria which power the nitrogen cycle
what is nitrogen fixation?
nitrogen gas reacts with hydrogen to form ammonia
bacteria needed for nitrogen fixing?
Azotobacter and Rhizobium
contain the enzyme nitrogenase
where is Azotobacter found?
found in the soil
where is Rhizobium found?
found in the root nodules of a plant
what is the relationship between Rhizobium and the plant called?
symbiotic mutualistic
why is the relationship between Rhizobium and the plant mutualistic?
the bacteria fix nitrogen into ammonia which is taken up by the plant as amino acids
the plant produces carbs which are used by bacteria for energy
what happens when soil is water logged?
no space for oxygen to reach bacteria in soil so aerobic respiration cannot take place
allows for denitrification…
nitrogen cycle diagram
