Final answer:
Endergonic and exergonic reactions involve energy changes in biological reactions. Endergonic reactions require input of energy and result in products with more energy. Exergonic reactions release energy and result in products with less energy.
Step-by-step explanation:
Endergonic and exergonic reactions are terms used in biology to describe the energy changes that occur during chemical reactions. Endergonic reactions require an input of energy to proceed and result in the formation of products with more energy than the reactants. Exergonic reactions, on the other hand, release energy and result in the formation of products with less energy than the reactants.
An example of an endergonic reaction is photosynthesis, where energy from sunlight is used to convert carbon dioxide and water into glucose. This process requires energy input in the form of light energy. An example of an exergonic reaction is cellular respiration, where glucose is broken down to release energy for the cell to use.
Activation energy is the energy required to initiate a chemical reaction. Both endergonic and exergonic reactions require a small amount of energy input, called activation energy, to overcome an activation barrier and start the reaction.