Answer:
The correct answer will be covalent peptide bond .
Step-by-step explanation:
Amino acids are the small molecules which act as building block of the proteins. Each amino acid consists of a central carbon atom called alpha (α)-C bonded to amino (NH₂) group, a carboxyl (COOH) group, hydrogen (H₂) atom and a variable side chain.
These amino acids form bond with each other by a process called dehydration synthesis process or condensation process in which a di-peptide bond is formed between α-amino (NH₂) group to α-carboxyl (COOH) group of next amino acid releasing water molecule.The bond formed between CO-NH groups is called a peptide bond. These peptide bond forms long linear chains of amino acids which form the primary structure of proteins.
Thus, covalent peptide bond is the correct answer.
The four-atom functional group -C(=O)NH- is called an amide group or (in the context of proteins) a peptide group.
Polypeptides and proteins are chains of amino acids held together by peptide bonds, as is the backbone of PNA.