What does activation energy refer to?

• A. The energy required to maintain homeostasis
• B. The energy needed to initiate a chemical reaction
• C. The energy released during exothermic reactions
• D. The energy produced by cellular respiration

Answer: (B)

Activation energy specifically refers to the minimum amount of energy needed to start a chemical reaction. This energy helps to break the bonds of reactants, allowing them to rearrange and form products. In biochemical reactions, overcoming this activation energy barrier is crucial for the reaction to proceed, and enzymes often play a role in lowering this energy requirement, thereby accelerating reactions within biological systems.

While the other choices discuss various aspects of energy in biological processes, they do not define activation energy. Maintaining homeostasis involves numerous processes within the body but does not directly relate to the initiation of chemical reactions. Energy released during exothermic reactions pertains to the outcome of a reaction rather than its initiation. The energy produced by cellular respiration is related to metabolic processes that occur after reactions have been initiated, rather than about the energy required to start those reactions.