Which term refers to the energy-releasing reactions in cellular metabolism?

In cellular metabolism, the term that refers to energy-releasing reactions is indeed associated with the concept of exergonic reactions. These reactions are characterized by a release of energy, typically in the form of ATP (adenosine triphosphate), which can then be utilized for various cellular processes.

During exergonic reactions, such as cellular respiration, complex molecules are broken down into simpler products, resulting in a net release of free energy. This is pivotal for cells, as it powers functions necessary for survival, including movement, biosynthesis, and maintaining homeostasis.

While the term "catabolic" also describes some energy-releasing processes, it specifically refers to the breakdown of larger molecules into smaller ones. All catabolic reactions are, by their nature, exergonic; however, the term exergonic directly emphasizes the thermodynamic aspect of energy release in broader contexts, not limited to only catabolic reactions.

The other terms provided do not fit the context as closely. "Endergenic" refers to reactions that require energy input, "photogenic" is typically not used in this context but can refer to processes involving light energy, and thus do not accurately define energy-releasing reactions.