AP BIOLOGY

Detailed explanation-1: -Exergonic reactions are also called spontaneous reactions, because they can occur without the addition of energy. Reactions with a positive ∆G (∆G > 0), on the other hand, require an input of energy and are called endergonic reactions.

Detailed explanation-2: -Photosynthesis. One of the most common examples of an endergonic reaction is the process of photosynthesis. Photosynthesis is used by all plants to convert light energy into a form of chemical energy that can be used to fuel their life processes. Photosynthesis doesn’t happen spontaneously.

Detailed explanation-3: -Endergonic reactions require an input of energy; the ∆G for that reaction will be a positive value. Exergonic reactions release free energy; the ∆G for that reaction will be a negative value.

Detailed explanation-4: -In metabolism, an endergonic process is anabolic, meaning that energy is stored; in many such anabolic processes energy is supplied by coupling the reaction to adenosine triphosphate (ATP) and consequently resulting in a high energy, negatively charged organic phosphate and positive adenosine diphosphate.

Detailed explanation-5: -Endergonic reactions absorb energy from their surroundings. The chemical bonds that are formed from the reaction are weaker than the chemical bonds that were broken. The free energy of the system increases. The change in the standard Gibbs Free Energy (G) of an endergonic reaction is positive (greater than 0).