In large proteins such as myoglobin and enzymes, peptide chains are much looped, twisted and folded back on themselves to form a tertiary structure. Which bonds are involved in the formation of tertiary structure of proteins?

The tertiary structure of proteins represents the overall three-dimensional folding of the polypeptide chain. This structure is stabilized by various non-covalent interactions, including hydrogen bonds, ionic bonds, van der Waals forces, and hydrophobic interactions.

While disulphide bonds (covalent linkages) can also stabilize the tertiary structure in some proteins, myoglobin is a classic example of a globular protein that completely lacks disulphide bonds. Its tertiary structure is stabilized entirely by non-covalent interactions, predominantly hydrogen bonds and hydrophobic interactions.

Looking at the other options:
1. Peptide bonds are responsible for the primary structure of proteins.
2. Glycosidic bonds are found in carbohydrates, not proteins.

Therefore, among the given choices, hydrogen bonds are the correct bonds involved in the formation of the tertiary structure of proteins like myoglobin.

Answer: Hydrogen bonds.