We can break reactions down into different types.

Anabolic and Catabolic

Endergonic and Exergoinc

Anabolic

Anabolism is the building up of larger molecules from smaller molecules. This process requires energy and is seen all throughout the body.

The most well known and possibly most important anabolic reaction is photosynthesis. Plants use the energy given off from the sun to create glucose.

Polymer building

When building a polymer, we remove a water molecule. This is called a dehydration reaction.

Catabolic

Catabolism is the opposite of anabolism. We breakdown macromolecules into smaller molecules.

This breaking of bonds, releases energy.
During cellular respiration we break the bonds in a glucose molecule and capture the energy released as ATP.

Polymer breaking

When breaking a polymer, we add water to the molecule. This is called a hydrolysis reaction.

The animation to the left, shows two amino acids being broken apart.

Exergonic reaction

These reactions result in a net releases of energy.

By breaking chemical bonds we release energy. Cells use this energy for their cellular processes.

The video to the right shows the amount of energy released when breaking down simple sugars. This is an exothermic reaction.

Click here for more info on exothermic and exergonic.

Endergonic reaction

These processes require an input of energy. Photosynthesis and protein synthesis are examples of endergonic reactions.