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O Levels Chemistry (5070)•5070/12/O/N/21
Question 16 from 5070/12/O/N/21

Explanation

Identifying the reaction as cellular respiration

Steps:

  • Recognize the equation C6H12O6 + 6O2 → 6CO2 + 6H2O as aerobic cellular respiration, where glucose is broken down to release energy.
  • Recall that respiration provides energy for all living cells and does not require light.
  • Eliminate options requiring light or plant-specific factors, as respiration is universal.
  • Confirm the correct statement matches respiration's characteristics: it proceeds in the absence of light.

Why B is correct:

  • Cellular respiration occurs continuously in living organisms, including in the dark, as it does not depend on light energy unlike photosynthesis.

Why the others are wrong:

  • A: The reaction is exothermic, releasing energy (ΔH negative), not endothermic.
  • C: Chlorophyll is a catalyst for photosynthesis, not respiration.
  • D: Respiration occurs in both plants and animals for energy production.

Final answer: B

Topic: Exothermic and endothermic reactions

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