NOVA Hunting the Elements Practice Test

Magnesium plays a central role as a cofactor in energy metabolism, the process by which cells harvest and use energy. It helps form and stabilize ATP, so enzymes actually work with Mg-ATP to drive reactions. Enzymes in glycolysis, the citric acid cycle, and oxidative phosphorylation rely on magnesium to function, and ATP synthase specifically needs Mg-ATP to produce energy currency for the cell. Because this involvement spans nearly all cells and tissues, energy metabolism is the body function most clearly tied to magnesium.

Magnesium also influences muscle relaxation and nerve conduction, in part by modulating calcium handling, but those roles are more specific regulatory effects. The broad, essential connection to turning nutrients into usable energy makes energy metabolism the best match.