How is energy typically stored in biological systems?

Energy in biological systems is primarily stored by chemical reactions, particularly in the form of molecules called adenosine triphosphate (ATP) and other energy-rich compounds. ATP acts as the most common energy currency in cells, allowing organisms to perform work by releasing energy when it breaks down into adenosine diphosphate (ADP) and inorganic phosphate.

In addition, energy is also stored in the bonds of larger molecules like carbohydrates, lipids, and proteins. When these molecules undergo chemical reactions—such as glycolysis, the Krebs cycle, and cellular respiration—the stored chemical energy can be converted into a form that the cell can use for various functions, including metabolic processes, cellular repair, and growth.

While other processes like electrical impulses and mechanical movement are important for cellular function and organismal activity, they do not directly relate to the storage of energy within the cells. Photosynthesis, while crucial for plants to capture energy from sunlight and convert it into chemical energy stored in glucose, is a specific example of how energy can be transformed but does not encompass the broader ways energy is stored in all biological systems.