Amino acids are organic compounds that serve as the building blocks of proteins. They contain an amino group, a carboxyl group, and a unique side chain that determines their specific properties. There are 20 standard amino acids, which combine in various sequences to form proteins essential for various biological functions, including growth, repair, and enzyme activity. In addition to their role in protein synthesis, amino acids also play crucial roles in metabolism and the production of hormones and neurotransmitters. Some amino acids are classified as essential, meaning they must be obtained through diet, while others are non-essential, as the body can synthesize them.