Difference between Exergonic Reactions and Endergonic Reactions

Main difference

The main difference between the exergonic and endergonic reaction is that the exergonic reaction is a spontaneous reaction, while the endergonic reaction is a non-spontaneous reaction.

Exergonic reaction vs. endergonic reaction

Exergonic is a favorable chemical reaction that has a negative Gibbs free energy. It indicates that an exergonic reaction is a spontaneous reaction since in this reaction the Gibbs energy has a negative value. In these types of reactions, energy is released into the environment, so the products have a lower amount of energy than the reactants. For this reason, the enthalpy change has a negative value for an exergonic reaction. The entropy increases in this reaction due to the disorder of the system. Exothermic reactions are also included in exergonic reactions. In contrast, the endergonic reaction is a type of reaction in which the Gibbs free energy has a positive value.A non-spontaneous reaction is also called an unfavorable reaction. In such kind of reaction, energy must be provided from outside the reaction for its progression. This is the reason why the products obtain a higher energy value than the reactants. The enthalpy change has a positive value. As new products are formed, the entropy of the system decreases. Endothermic reactions are also included in endergonic reactions.

Exergonic reactions can also be called catabolism (destructive part of metabolism) when complex molecules are broken down, while endergonic reactions can also be called anabolism (creative part of metabolism) when new complex molecules are formed from simple molecules.

Comparative chart

Exergonic reaction Endergonic reaction
The exergonic reaction is a spontaneous reaction in which energy is released to the environment An endergonic reaction is a non-spontaneous reaction in which energy is absorbed from the environment.
Synonyms
Exothermic reaction Endothermic reaction
Gibbs free energy value
Negative Positive
The entropy of the system
Increases Decreases
Examples
Sodium and chlorine mixture to make table salt, combustion, chemiluminescence Protein synthesis, nerve conduction, muscle contraction and sodium-potassium pumping in the cell membrane.
What is the exergonic reaction?

Gibbs free energy is a thermodynamic potential that is used to identify whether a reaction is spontaneous or non-spontaneous. A negative value for Gibbs free energy shows that the reaction is spontaneous and a positive value shows that the reaction is not spontaneous. The exergonic reaction is an irreversible reaction that occurs spontaneously in nature. It means that you are ready or eager to happen with very little external stimulus. An example of such a reaction is the combustion of sodium when exposed to oxygen present in the air. The burning of a log is another example of an exergonic reaction. These reactions release more heat and are called favorable reactions in the thermodynamic field. Gibbs free energy is negative under constant pressure and temperature, which means that more energy is released than is absorbed. Cellular respiration is a classic example of this. Almost 3012 kJ of energy is released when a glucose molecule is converted to carbon dioxide. Organisms use this energy for other cellular activities. All catabolic reactions, for example, the breakdown of carbohydrates, fats, and proteins releases energy for living organisms to do their work. Some exergonic reactions do not occur spontaneously and require a small amount of energy to initiate the reaction. Once an external source meets this energy requirement, the reaction proceeds to break the bonds and form new bonds, and energy is released as the reaction occurs. This results in a net energy gain to the environment and a net energy loss to the reaction system. Organisms use this energy for other cellular activities. All catabolic reactions, for example, the breakdown of carbohydrates, fats and proteins release energy for living organisms to do their work. Some exergonic reactions do not occur spontaneously and require a small amount of energy to initiate the reaction. Once an external source meets this energy requirement, the reaction proceeds to break the bonds and form new bonds and energy is released as the reaction occurs. This results in a net energy gain to the environment and a net energy loss to the reaction system. Organisms use this energy for other cellular activities. All catabolic reactions, for example, the breakdown of carbohydrates, fats, and proteins releases energy for living organisms to do their work. Some exergonic reactions do not occur spontaneously and require a small amount of energy to initiate the reaction. Once an external source meets this energy requirement, the reaction proceeds to break the bonds and form new bonds, and energy is released as the reaction occurs. This results in a net energy gain to the environment and a net energy loss to the reaction system. Some exergonic reactions do not occur spontaneously and require a small amount of energy to initiate the reaction. Once an external source meets this energy requirement, the reaction proceeds to break the bonds and form new bonds and energy is released as the reaction occurs. This results in a net energy gain to the environment and a net energy loss to the reaction system. Some exergonic reactions do not occur spontaneously and require a small amount of energy to initiate the reaction. Once an external source meets this energy requirement, the reaction proceeds to break the bonds and form new bonds and energy is released as the reaction occurs. This results in a net energy gain to the environment and a net energy loss to the reaction system. The reaction proceeds to break the bonds and form new bonds and energy is released as the reaction occurs. This results in a net energy gain to the environment and a net energy loss to the reaction system. Some exergonic reactions do not occur spontaneously and require a small amount of energy to initiate the reaction. Once an external source meets this energy requirement, the reaction proceeds to break the bonds and form new bonds, and energy is released as the reaction occurs. This results in a net energy gain to the environment and a net energy loss to the reaction system. The reaction proceeds to break the bonds and form new bonds and energy is released as the reaction occurs. This results in a net energy gain to the environment and a net energy loss to the reaction system. Some exergonic reactions do not occur spontaneously and require a small amount of energy to initiate the reaction. Once an external source meets this energy requirement, the reaction proceeds to break the bonds and form new bonds and energy is released as the reaction occurs. This results in a net energy gain to the environment and a net energy loss to the reaction system. This results in a net energy gain to the environment and a net energy loss to the reaction system. Some exergonic reactions do not occur spontaneously and require a small amount of energy to initiate the reaction. Once an external source meets this energy requirement, the reaction proceeds to break the bonds and form new bonds and energy is released as the reaction occurs. This results in a net energy gain to the environment and a net energy loss to the reaction system. This results in a net energy gain to the environment and a net energy loss to the reaction system. Some exergonic reactions do not occur spontaneously and require a small amount of energy to initiate the reaction. Once an external source meets this energy requirement, the reaction proceeds to break the bonds and form new bonds, and energy is released as the reaction occurs. This results in a net energy gain to the environment and a net energy loss to the reaction system. The reaction proceeds to break the bonds and form new bonds and energy is released as the reaction occurs. This results in a net energy gain to the environment and a net energy loss to the reaction system. The reaction proceeds to break the bonds and form new bonds and energy is released as the reaction occurs. This results in a net energy gain to the environment and a net energy loss to the reaction system.

What is the endergonic reaction?

There are many chemical reactions that occur only when a sufficient amount of energy has been supplied from the environment. By themselves, these reactions cannot occur. External energy helps break these bonds. The energy released by the breaking of the bonds that maintains the reaction. This energy is not enough to sustain the reaction and external energy is needed. These reactions are called endergonic reactions. Protein synthesis is an anabolic reaction that requires small amino acids to bind together to form a protein molecule. It takes a lot of energy to make peptide bonds. The sodium-potassium pump in the cell membrane is involved in pumping sodium ions and moving potassium ions against the concentration gradient to allow call depolarization and nerve conduction. This movement against the gradient requires a lot of energy that comes from the breakdown of the ATP molecule. Similarly, muscle contraction can only occur when the existing bonds between actin and myosin fibers are broken to form new bonds. This also requires a great deal of energy. Photosynthesis in plants is another example of an endergonic reaction. The leaf has glucose and water, but it cannot make food. Sunlight is the external source of energy that starts it. This movement against the gradient requires a lot of energy that comes from the breakdown of the ATP molecule. Similarly, muscle contraction can only occur when the existing bonds between actin and myosin fibers are broken to form new bonds. This also requires a great deal of energy. Photosynthesis in plants is another example of an endergonic reaction. The leaf has glucose and water, but it cannot make food. Sunlight is the external source of energy that starts it. This movement against the gradient requires a lot of energy that comes from the breakdown of the ATP molecule. Similarly, muscle contraction can only occur when the existing bonds between actin and myosin fibers are broken to form new bonds. This also requires a great deal of energy. Photosynthesis in plants is another example of an endergonic reaction. The leaf has glucose and water, but it cannot make food. Sunlight is the external source of energy that starts it. The leaf has glucose and water, but it cannot make food. Sunlight is the external source of energy that starts it. The leaf has glucose and water, but it cannot make food. Sunlight is the external source of energy that starts it.

Key differences
  1. The exergonic reaction is a spontaneous reaction, while the endergonic reaction is a non-spontaneous reaction.
  2. The exergonic reaction does not need energy to happen, while the endergonic reaction needs energy.
  3. In the exergonic reaction, energy is released into the environment, while in the endergonic reaction, energy is absorbed from the environment.
  4. In the exergonic reaction, the bonds that are formed are stronger than the bonds that break, while in the endergonic reaction the bonds that are formed are weaker than the bonds that break.
  5. In the exergonic reaction, the free energy of the system decreases while, in the endergonic reaction, the free energy of the system increases.
  6. In the exergonic reaction, the change in entropy increases while in the endergonic reaction the change in entropy decreases.
  7. In the exergonic reaction, the Gibb free energy is a negative value while, in the endergonic reaction, the Gibbs free energy is a positive value.

Final Thought

From the above discussion it has been concluded that all chemical reactions can be characterized as exergonic or endergonic reactions, but both have opposite properties.

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