Dehydration synthesis is a chemical reaction that combines two molecules by removing a water molecule. This process is essential in forming larger biological molecules, such as carbohydrates, proteins, and nucleic acids. During the reaction, a hydroxyl group (–OH) from one molecule and a hydrogen atom (–H) from another are eliminated, resulting in the formation of a covalent bond between the two molecules. This type of reaction is crucial for building complex structures in living organisms. For example, when simple sugars like glucose undergo dehydration synthesis, they can form larger carbohydrates like starch or glycogen. Similarly, amino acids link together to create proteins through this process, highlighting its importance in biological systems.