CAIE IGCSE Biology 19.3 Nutrient cycles Question Bank
Practise nutrient-cycle questions by matching carbon-cycle arrows and interpreting nitrogen-cycle processes, ions and bacterial roles in diagrams.
- Syllabus
- 2026–2028
- Course
- Biology 0610
Exam points
- match carbon-cycle arrows to photosynthesis, respiration, combustion and fossil fuels
- identify nitrogen fixation, nitrification, decomposition and denitrification in diagrams
- track ammonium ions, nitrate ions, amino acids, proteins and nitrogen gas through the cycle
Covered syllabus points
19.3 Nutrient cycles question 1
Question (a)
(a)
Fig. 6.1 shows part of the carbon cycle in the ocean.
Fig. 6.1 (not to scale)
[ 4 ]
Question (i)
(i)
Phytoplankton contain chlorophyll.
Explain how phytoplankton lower carbon dioxide concentrations in the atmosphere.
[ 2 ]
Question (ii)
(ii)
State the names of two processes that add carbon dioxide to the atmosphere.
1
2
[ 2 ]
19.3 Nutrient cycles question 2
Fig. 5.1 is a diagram of a plant root hair cell.
Key
× nitrate ion
- water molecule
Fig. 5.1
State two ways that nitrogen fixation occurs.
19.3 Nutrient cycles question 3
A student investigated the effect of high temperature on the production of nitrate ions in soil.
Two samples of soil were taken. One sample was heated to .
All the nitrate ions were completely removed from both soil samples.
Ammonium ions were then added to both soil samples.
After two weeks, both soil samples were tested for the presence of nitrate ions.
The results are shown.
Which statement explains the results?
A
Heating the soil broke down the nitrate ions.
B
Heating the soil increased the activity of denitrifying bacteria.
C
Heating the soil killed nitrifying bacteria.
D
Heating the soil killed nitrogen-fixing bacteria.
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