How does photosynthesis use light energy to form chemical energy?

• A. Plants store energy as ATP without glucose.
• B. Plants use sunlight to produce energy without glucose.
• C. Plants convert chemical energy into light energy.
• D. Plants convert light energy into chemical energy stored in glucose during photosynthesis.

Answer: (D)

Light energy from the sun is captured by chlorophyll and used to drive the synthesis of glucose, storing energy in the chemical bonds of that sugar. In the first stage, light energy is converted into chemical energy in the form of ATP and NADPH. Those molecules then power the second stage, where carbon dioxide is fixed into organic molecules and eventually built up into glucose. The energy is stored in the glucose molecule’s bonds, so later, when respiration occurs, that chemical energy can be released to power cellular processes. Oxygen is released as a byproduct when water is split to provide electrons for the light-dependent reactions.