This scientific illustration depicts the molecular structure of peptides, highlighting the transition from primary sequence to tertiary folding. On the left, the primary peptide sequence shows amino acids linked by peptide bonds, including leucine and glycine, with detailed atom-level interactions such as amino and carboxyl groups. The middle section illustrates secondary structures, including the alpha helix and beta-pleated sheet, emphasizing hydrogen bonds stabilizing these forms. The right section presents the tertiary structure, showcasing complex folding stabilized by hydrogen bonds, ionic bonds or salt bridges, hydrophobic interactions, and disulfide bridges. A color-coded key identifies different atoms and groups, providing clarity to the molecular components.