What are amino acids?

Amino acids are the fundamental building blocks of proteins, making them essential for the synthesis of all proteins in living organisms. Each protein is formed by linking together a specific sequence of amino acids through peptide bonds. This sequence determines the protein's unique structure and function. There are 20 standard amino acids, and they combine in various ways to create thousands of different proteins, each with specific roles in metabolism, structure, signaling, and other biological processes.

The other options describe different biological molecules. Vitamins are organic compounds that are vital for metabolic processes but cannot be synthesized by the body and serve various roles in health. Complex carbohydrates are composed of sugar molecules and serve as a primary energy source, whereas fatty acids are components of lipids that play crucial roles in energy storage and structural functions within cell membranes.