Which molecule serves as the building blocks of proteins?

Amino acids are the fundamental building blocks of proteins. Each protein is composed of one or more chains of amino acids, which are linked together by peptide bonds formed during a process called translation. There are 20 different amino acids that can combine in various sequences to form proteins, and the specific order of amino acids determines the structure and function of each protein.

Proteins play a vital role in nearly every biological process, including catalyzing metabolic reactions, providing structural support, transporting molecules, and regulating cellular functions. Therefore, understanding that amino acids are the precursors for proteins is essential in the study of biology.

The other molecules listed serve different roles: nucleotides are the basic units of nucleic acids like DNA and RNA; fatty acids are components of lipids; and monosaccharides are the simplest forms of carbohydrates. Each of these plays critical roles in biological systems but is not involved in the formation of proteins.