Chains of joined amino acids are known as what?

Chains of joined amino acids are known as polypeptide chains. Polypeptides are formed when amino acids are linked together through peptide bonds, resulting in a chain-like structure. This process is a fundamental aspect of protein synthesis, where the specific sequence of amino acids in a polypeptide is determined by the genetic code. These chains can fold into complex three-dimensional shapes that are essential for the biological function of proteins in living organisms.

The other options refer to different types of biological molecules: carbohydrate chains consist of sugar units and are involved in energy storage and structural components; lipid chains are made of fatty acids and play a role in forming cell membranes and storing energy; nucleic acid chains are polymers of nucleotides that form DNA and RNA, which are crucial for genetic information. Each of these biomolecules has distinct structures and functions that are separate from those of proteins, highlighting the unique role that polypeptides play in biological systems.