[Campbell Biology P.198] According to the provided text, what is the most accurate statement... | Practice Question

According to the provided text, what is the most accurate statement regarding the energy associated with chemical bonds in biological reactions?

  • A: The breaking of chemical bonds in molecules like sugar directly releases large amounts of free energy.
  • B: "Energy stored in bonds" primarily refers to the potential energy released when new, more stable bonds are formed.
  • C: Energy is released when bonds are broken and absorbed when new bonds are formed, regardless of the relative free energy of reactants and products.
  • D: All bond formations in biological systems are exergonic, while all bond breakages are endergonic.

Explanation

The text clarifies a common misconception by stating that 'the breaking of bonds does not release energy; on the contrary, as you will soon see, it requires energy.' It then explains that 'the phrase "energy stored in bonds" is shorthand for the potential energy that can be released when new bonds are formed after the original bonds break, as long as the products are of lower free energy than the reactants.' This means the energy released in exergonic reactions comes from the formation of new, more stable bonds, not the breaking of old ones.