Is energy released or absorbed during photosynthesis?

• A. Released
• B. Neither
• C. Both
• D. Absorbed

Answer: (D)

In photosynthesis, energy is stored rather than released. Sunlight provides the energy to build glucose from carbon dioxide and water. The light reactions capture light energy and convert it into chemical energy in ATP and NADPH, which then powers the Calvin cycle to synthesize sugars. Because energy must be absorbed to form these larger, energy-rich molecules, the overall process is endergonic, with energy stored in the chemical bonds of the glucose. (For contrast, energy is released during cellular respiration when glucose is broken down.)