What are the building blocks of proteins?

The correct answer, amino acids, are indeed the building blocks of proteins. Proteins are complex molecules essential for a variety of biological functions, and they are made up of long chains of amino acids that are linked together by peptide bonds. Each protein's unique sequence of amino acids determines its structure and function, and there are 20 different amino acids that can be combined in countless ways to create the diverse range of proteins found in living organisms.

Amino acids play critical roles in various biological processes, including enzyme catalysis, immune responses, and signaling pathways. When proteins are synthesized in cells, specific sequences of amino acids are translated from messenger RNA, emphasizing the foundational role of amino acids in protein synthesis.

The other options listed pertain to different macromolecules: fatty acids are the building blocks of lipids, sugars are the basic units of carbohydrates, and carbohydrates themselves are a distinct type of macromolecule characterized by their sugar units. Therefore, amino acids are the specific substances that directly relate to the structure and formation of proteins.