O Levels Biology (5090)•5090/12/M/J/23

Explanation
Energy balance in biological processes
Steps:
- Define energy loss as net expenditure from the organism's stored or captured resources.
- Evaluate photosynthesis: plants capture solar energy and store it as glucose, gaining energy overall.
- Assess other options: respiration, thermoregulation, and germination all consume stored energy without external input.
- Identify the process with net energy gain as the one without overall loss.
Why A is correct:
- Photosynthesis follows the equation 6CO₂ + 6H₂O + light → C₆H₁₂O₆ + 6O₂, converting light energy into chemical energy stored in glucose.
Why the others are wrong:
- B: Respiration (C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP + heat) releases stored energy as ATP and heat, resulting in net loss.
- C: Temperature control uses metabolic energy for processes like shivering or sweating to maintain homeostasis.
- D: Germination mobilizes seed reserves (e.g., starch) for growth, depleting stored energy.
Final answer: A
Topic: Photosynthesis
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