Question

What does a protein lose when it denatures?
(a) Its primary structure
(b) Its sequence of amino acids
(c) Its three-dimensional shape
(d) Its peptide bonds

Answer 1

Protein is a polymer of amino acid which forms by a formation of peptide bonds. Protein is the most important macromolecules of organisms and organizes into four structures primary, secondary, tertiary, and quaternary.

Complete answer:
Protein forms four types of structure on the basis of its polypeptide chain arrangement. The only tertiary structure of protein denatures due to high temperature, pressure, change in pH. Some metal ions, detergent, and alcohol also cause denaturation.
The tertiary structure of a protein is a helical polypeptide molecule which after folding forms a spherical or rod-like structure. In the case of tertiary structure alpha helix and beta pleated protein form a three-dimensional shape after twisting and bending. The tertiary structure of a protein is thermodynamically most stable but denaturation of this structure is caused due to the presence of non-covalent bonds.

Additional Information: The primary structure of a protein is the linear arrangement of the polypeptide. These polypeptide chains are joined by disulfide bonds.
The secondary structure of a protein is formed by folding the long polypeptide chain. Between these bond H bond forms which stabilizes the secondary structure of a protein. Alpha, beta, and collagen helix are three types of secondary structure of the protein. Alpha helix form when polypeptide arranged in the right-handed coil. Beta helix form by two or more parallel zig-zag polypeptide chains which form a sheet-like structure. In collagen helix three beta-pleated polypeptide coils around one another.
The quaternary structure formed by the packing of the tertiary structure. Different subunits in this fit the structure into specific conformation.
In the case of the tertiary structure after denaturation, protein renature when denaturing agents are removed and the formation of noncovalent bonds takes place.
So, the correct answer is Its three-dimensional space.

Note: Protein was discovered by Mulder but protein term was first suggested by Berzelius. Proteins are insoluble in water and exist in colloidal form. A body requires 1g protein per Kg of body weight. Protein does not store in the body therefore protein is the essential nutrient that is required in everyday meals.