IB ESS HL 2.3.18 Hl Bacterial Roles in Nitrogen Cycle Questions
Explain bacterial fixation, nitrification, denitrification and decomposition in the nitrogen cycle.
- Syllabus
- First assessment 2026
- Course
- ESS HL
- Level
- HL
Exam points
- label and complete nitrogen-cycle diagrams by identifying stores and bacterial processes such as nitrogen fixation, nitrification and decomposition/ammonification
- trace atmospheric nitrogen through bacterial transformations, plant assimilation and transfer into decomposer protein
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IB ESS HL 2.3.18 Hl Bacterial Roles in Nitrogen Cycle Questions question 1
[Maximum number: 4]
Outline the processes by which nitrogen in the atmosphere may eventually be found in the protein of a decomposer.
nitrogen cycles within ecosystems/is recycled in the Earth system;
b. nitrogen gas may diffuse into the soil;
c. nitrifying bacteria convert the nitrogen to ammonium/nitrites;
d. further bacteria convert the nitrites to nitrates;
e. lightning transforms/oxidises the nitrogen to nitrates;
f. nitrates are taken up by the roots of plants;
g. nitrates are transferred to the leaves of plants;
h. nitrates are assimilated into organic molecules/amino acids/proteins/nucleic acids in the plant;
i. the leaf/plant dies and enters the soil/becomes detritus;
j. the proteins are consumed/absorbed by decomposers/detritivores/saprotrophs;
Note: Marking points may be credited if conveyed explicitly by an appropriate annotated diagram.
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