Question

What is a coupled reaction? What is its importance in biological reactions?

Short answer

A coupled reaction in biological systems is where an energy-releasing (exothermic) reaction happens simultaneously with an energy-requiring (endothermic) reaction, often using ATP hydrolysis as the exothermic reaction. This allows for the powering of processes that wouldn't otherwise occur due to energy requirements. It is fundamental to many crucial physiological processes.

Step-by-step solution

Understanding Coupled Reactions

A coupled reaction is a type of reaction in which an exothermic reaction (one that releases energy) drives an endothermic reaction (one that requires energy to proceed). Often, this involves the hydrolysis of ATP (Adenosine TriPhosphate), a molecule that stores a highly useful form of chemical energy. ATP hydrolysis is exothermic, releasing energy that can be used to power less favorable reactions.

Significance of Coupled Reactions in Biological Systems

Coupled reactions are extremely significant in biological systems. The energy released from exothermic reactions like ATP hydrolysis, can 'fuel' simultaneously occurring endothermic reactions, allowing them to proceed when they otherwise wouldn't. This is how cells in our bodies carry out various essential processes that require energy, such as active transport across cell membranes, operating motor proteins, and synthesizing large molecules.