How do cells derive energy from the food we eat?

The food that we eat is broken down into simpler chemicals and the cells end up with glucose molecules. They use these glucose molecules to generate energy through a process known as cellular respiration. Chemically this process can be represented by the following equation:

`C_6H_12O_6 + 6O_2 -> 6CO_2 + 6H_2O + ATP`

In this process, each mole of glucose reacts with 6 moles of oxygen and generates 6 moles of carbon dioxide, 6 moles of water and (most importantly) ATP molecules. These ATP or adenosine triphosphate molecules are the energy of the cell.

The breakdown of glucose can be done both aerobically (in the presence of oxygen) as well as anaerobically (in the absence of oxygen). However, a much higher quantity of ATP molecules is generated when the reaction takes place in the presence of oxygen as compared to its absence.

Hope this helps.