During which type of reaction is energy consumed?

In an endergonic reaction, energy is consumed in order to proceed. This type of reaction requires an input of energy because the products possess more energy than the reactants. Typically, endergonic reactions are associated with processes such as photosynthesis, where energy from sunlight is absorbed to convert carbon dioxide and water into glucose and oxygen.

The term "endergonic" itself indicates that the change in free energy is positive, reflecting the need for energy input for the reaction to occur. This contrasts with other types of reactions. For instance, spontaneous reactions, while they may release energy, do not require an external energy input, and exergonic reactions result in a net release of energy. Similarly, catabolic reactions usually break down molecules and typically release energy rather than consuming it. Therefore, endergonic reactions specifically highlight the requirement for energy consumption, making this the correct choice for the question regarding which type of reaction consumes energy.