Group transfer reactions are chemical processes where a specific group of atoms or molecules is transferred from one reactant to another. This type of reaction is essential in various biochemical pathways, as it allows for the modification of molecules, facilitating complex transformations necessary for life. One common example of a group transfer reaction is the transfer of a phosphate group from ATP (adenosine triphosphate) to another molecule. This process is crucial in cellular energy transfer and metabolism, as it helps activate or deactivate enzymes and other proteins, influencing numerous biological functions.