Final answer:
The light that strikes the leaves of a plant isn't all stored as chemical energy due to energy loss as heat, environmental factors such as water and nutrient limits, efficiency of light-harvesting structures, and energy costs of photosynthesis.
Step-by-step explanation:
Not all the light that strikes the leaves of a plant is stored as chemical energy due to several factors involved in the process of photosynthesis. First, light energy is absorbed by chlorophyll and other pigments in the leaves, but this is just the initial step. The energy must be transferred efficiently to the reaction center to eventually be used in the synthesis of glucose. However, during this process, some of the light energy is lost as heat or is reflected and not absorbed.
In addition, the efficiency of photosynthesis is affected by environmental factors such as water and nutrient availability. The energy conversion rates in plants range from around 0.01% to 6%, based on various conditions. Thus, a significant portion of light is not transformed into chemical energy. The physical structure of the photosystems and light-harvesting complexes also determines the efficiency of energy capture and conversion.
Some energy is used up while it 'travels' between molecules, in doing small cellular tasks, before reaching the reaction center. Moreover, the chemistry of life allows only certain forms of energy to be utilized, and the complicated biochemical pathways involved in photosynthesis have associated energy costs that further reduce the total energy stored.