Which bond is the backbone of all protein molecules?

Which bond is the backbone of all protein molecules?

• A. Salt bond
• B. Keratin
• C. Peptide
• D. Hydrogen bond

Answer: (C)

Proteins are built from amino acids connected by peptide bonds, forming a continuous polypeptide chain. This covalent linkage occurs when the carboxyl group of one amino acid bonds to the amino group of the next, releasing a water molecule in a dehydration synthesis reaction. The result is a repeating backbone of covalent bonds (often described as -N-C-C- along the chain) that holds the protein together, while the side chains (R groups) extend from this backbone and give each protein its unique properties. Hydrogen bonds and other interactions help the chain fold into its functional shapes, but they are interactions within the structure, not the main scaffold. Salt bonds are ionic interactions between charged side chains, and keratin is a type of protein, not a bond. This is why the peptide bond is the backbone of all protein molecules.

Proteins are built from amino acids connected by peptide bonds, forming a continuous polypeptide chain. This covalent linkage occurs when the carboxyl group of one amino acid bonds to the amino group of the next, releasing a water molecule in a dehydration synthesis reaction. The result is a repeating backbone of covalent bonds (often described as -N-C-C- along the chain) that holds the protein together, while the side chains (R groups) extend from this backbone and give each protein its unique properties. Hydrogen bonds and other interactions help the chain fold into its functional shapes, but they are interactions within the structure, not the main scaffold. Salt bonds are ionic interactions between charged side chains, and keratin is a type of protein, not a bond. This is why the peptide bond is the backbone of all protein molecules.