Final answer:
ATP is regenerated using energy from the breakdown of glucose, fructose, or galactose, linking the exergonic and endergonic pathways that power cells.
Step-by-step explanation:
ATP is the primary source of energy for cells and must be regenerated after its energy has been expended. This regeneration process uses energy released from the breakdown of molecules such as glucose, fructose, or galactose, which are all isomers with the chemical formula C6H₁₂O₆.
The breakdown of these sugars during cellular respiration allows for the creation of ATP, linking the exergonic pathways of glucose catabolism with the endergonic pathways that power cells. Structurally, ATP consists of an adenine, a ribose, and three phosphate groups, with the bond between the second and third phosphate groups being the key to its energy-storing capacity.
When cells require energy, this bond is broken, resulting in adenosine diphosphate (ADP) and a free phosphate group, ready to be recycled back into ATP with the infusion of energy from nutrient breakdown.