Advanced Placement (AP) Biology Practice Exam

Which type of energy can be converted into chemical energy through photosynthesis?

1. Mechanical energy

2. Light energy

3. Kinetic energy

4. Electrical energy

The correct answer is: Light energy

Light energy is the primary energy source that can be converted into chemical energy during the process of photosynthesis. In photosynthesis, chlorophyll and other pigments in plant cells absorb light energy, typically from the sun. This energy is then used to drive the reaction that converts carbon dioxide and water into glucose and oxygen. The glucose produced is a form of chemical energy that plants can utilize for growth, reproduction, and other metabolic functions. The process fundamentally involves the transformation of light energy into chemical energy stored in the bonds of glucose molecules. This is a critical function in ecosystems, as it forms the basis for the energy supply for virtually all living organisms, either directly or indirectly. In the context of the other energy types listed, mechanical energy refers to energy possessed by an object due to its motion or position; kinetic energy is related to the motion of an object; and electrical energy relates to the movement of electrons. None of these directly participate in the conversion processes that define photosynthesis. Hence, while they are forms of energy used in various biological processes, they do not convert to chemical energy in the specific way that light energy does during photosynthesis.