Which process involves the conversion of chemical energy into usable energy in cells?

Cellular respiration is the process that involves the conversion of chemical energy into usable energy in cells. During this process, organic molecules, primarily glucose, are broken down in the presence of oxygen to produce adenosine triphosphate (ATP), which is the energy currency of the cell. The overall reaction takes place in several stages, including glycolysis, the Krebs cycle, and the electron transport chain, ultimately leading to the production of ATP, carbon dioxide, and water.

This conversion is fundamental for cellular functions, as ATP is necessary for powering various biological processes, including muscle contraction, nerve impulse propagation, and biochemical synthesis. By creating ATP from the chemical energy stored in nutrients, cellular respiration enables cells to perform work, grow, and reproduce effectively.

Other processes like photosynthesis and fermentation also involve energy transformation, but they do so in different contexts. Photosynthesis converts light energy into chemical energy stored in glucose, primarily in plants. Fermentation is an anaerobic process that occurs when oxygen is not present, allowing organisms to generate energy without using the full cellular respiration pathway, but it is less efficient than aerobic respiration. Transpiration involves the movement of water within plants and is not directly related to energy conversion.