DP Biology (first assessment 2025)

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Question 23M.2.SL.TZ2.c

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Date May 2023 Marks available [Maximum mark: 7] Reference code 23M.2.SL.TZ2.c
Level SL Paper 2 Time zone TZ2
Command term Describe Question number c Adapted from N/A
c.
[Maximum mark: 7]
23M.2.SL.TZ2.c

Describe processes in the carbon cycle that produce or use carbon dioxide.

[7]

Markscheme
  1. photosynthesis uses carbon dioxide / reduces carbon dioxide concentration of the atmosphere;
  2. autotrophs/plants/cyanobacteria convert/fix carbon dioxide into carbon/organic compounds;
  3. cell respiration produces/releases carbon dioxide;
  4. glucose/carbon/organic compounds oxidised/broken down to produce/release carbon dioxide;
  5. carbon dioxide released from aerobic (cell) respiration AND anaerobic respiration in yeast/plants (but not animals);
  6. carbon dioxide released from saprotrophs/detritivores/decomposers from dead organic matter / during decay/decomposition/respiration;
  7. (partially) decomposed organic matter can lead to the formation of peat /fossilized organic matter (coal/oil/natural gas)
  8. carbon dioxide released when carbon/organic compounds burn / during combustion (of biomass/fossil fuels) / forest fires;
  9. carbon dioxide dissolves in aquatic ecosystems / can form carbonic acid/hydrogen carbonate ions;
  10. reef-building corals/molluscs use calcium carbonate to make/build shells/exoskeletons or other body parts;
  11. hard parts/shells/exoskeletons / precipitation of calcium carbonate to form limestone/tufa;

Clear annotated diagrams with correct direction of arrows are accepted.

Syllabus sections