Advanced Placement (AP) Biology Practice Exam

Peptide bonds are formed through what type of reaction?

1. Hydrolysis reaction

2. Dehydration synthesis reaction

3. Oxidation reaction

4. Reduction reaction

The correct answer is: Dehydration synthesis reaction

Peptide bonds are formed through a dehydration synthesis reaction, also known as condensation reaction. In this process, two amino acids come together, and a molecule of water is removed as the carboxyl group of one amino acid reacts with the amino group of another. This reaction results in the formation of a covalent bond between the two amino acids, creating a peptide bond. In the context of protein synthesis, this type of reaction is essential because it allows for the sequential linkage of amino acids to form peptides and proteins. The removal of water is a key characteristic of dehydration synthesis, indicating that the process involves the combination of smaller molecules into larger structures while releasing water as a byproduct. Understanding this reaction is crucial for grasping how proteins are constructed and the way they function in biological systems, as the specific sequence and number of amino acids determined by peptide bonds ultimately dictate a protein's structure and function.