Final answer:
Activation energy is the minimum energy needed for all chemical reactions, including exergonic reactions which release energy, and endergonic reactions, which require net energy input and are non-spontaneous. Energetics in chemical reactions refers to the energy changes during conversion of reactants to products and is crucial in metabolism. Enzymes facilitate biochemical reactions by lowering the required activation energy.
Step-by-step explanation:
When discussing endergonic and exergonic reactions, one must consider activation energy. Activation energy, abbreviated as ÉA, is the small amount of energy required for all chemical reactions to occur, including exergonic ones. Despite exergonic reactions releasing energy overall, they still necessitate this initial energy input to get started. Contrarily, endergonic reactions absorb energy; thus, the products of these reactions have more total energy than the reactants, meaning they are non-spontaneous and require a net input of energy from the surroundings.
Energetics of chemical reactions involves two concepts: thermodynamics, the energy released or absorbed during the conversion of reactants to products, and kinetics, the energy necessary to overcome the energy barrier to product formation. In metabolic reactions like digestion, exergonic reactions, which release energy, are involved in breaking down complex molecules, while endergonic reactions consume energy to build large molecules from smaller ones.
Enzymes play a crucial role in facilitating biochemical reactions since most are unable to proceed quickly enough under the normal conditions within living organisms. By lowering the activation energy, enzymes help biochemical reactions take place by allowing the reactants to overcome the energy barrier more efficiently.