What happens to the remaining energy from glucose that is not converted into ATP?

The remaining energy from glucose that is not converted into ATP is primarily released as heat. During cellular respiration, glucose undergoes a process of oxidation, which involves a series of chemical reactions that break down the molecule to extract energy. Although much of this energy is captured in the form of ATP, some energy is inevitably lost due to the inefficiency of the process and the inherent nature of biochemical reactions.

As a result of these processes, the excess energy that cannot be harnessed for biochemical work is dissipated into the environment, primarily as heat. This thermodynamic principle is important for maintaining body temperature and homeostasis in living organisms, especially in more complex organisms that require stable internal conditions.

While there are other biological pathways for energy storage or usage, such as converting excess energy into fat, the immediate fate of the unutilized energy during cellular respiration is its release as heat. This phenomenon illustrates the balance between energy production, usage, and the thermodynamics of metabolic processes.