What occurs when glucose molecules are broken apart during cellular respiration?

A) The heat produced is used to drive biological reactions.
B) Oxygen is released and used as an energy source.
C) The energy released is used in ATP synthesis.
D) ATP is converted into ADP.
E) ADP is released as a waste product.

Glucose molecules are broken down during cellular respiration, and the energy released is used to synthesize ATP. Specifically, during the process of oxidative phosphorylation, electron transport chains transfer electrons from NADH and FADH2 to oxygen, releasing energy that is used to pump protons across a membrane. This sets up a proton gradient that is used by ATP synthase to generate ATP from ADP and Pi. Thus, the energy released during glucose catabolism is ultimately harnessed to drive ATP synthesis.