Question

For synthesis of a glucose molecule (with 686 kcal) the energy utilized during photosynthesis is

• A. 288 kCal
• B. 436 kCal
• C. 7914 kCal
• D. 686 kCal

Answer 1

Answer: (D)

686 kCal

Plants usually convert light into chemical energy with a photosynthetic efficiency of 3 to 6%. The absorbed light that is unconverted is dissipated primarily as heat, with a small fraction, which accounts nearly 1 to 2 %, re-emitted as chlorophyll fluorescence at longer wavelengths. When 1 mol (180 g) of glucose reacts with oxygen under standard conditions, 686 kcal of energy is released.

So, the correct answer is option D.