Question: 71: The incorrect statement about denaturation of proteins is
(1) It results due to change of temperature and/or pH
(2) It results in loss of biological activity of proteins.
(3) A protein is formed from amino acids linked by peptide bonds.
(4) Uncoiling of the helical structure takes place.
Answer: Option (3)
Explanation:
Denaturation of proteins refers to the disruption of the native structure of a protein due to
external factors like temperature, pH, or chemicals.
A change in temperature and/or pH can break hydrogen bonds and other weak interactions present in the secondary and tertiary structures of proteins, leading to denaturation.
Therefore, statement (1) is correct.
When a protein is denatured, its specific three-dimensional structure is lost,
which results in the loss of biological activity. Hence, statement (2) is correct.
During denaturation, the helical or folded structure of the protein uncoils due to
breaking of hydrogen bonds. Thus, statement (4) is also correct.
Statement (3) describes the formation of proteins from amino acids linked by peptide bonds,
which is related to the primary structure of proteins.
Denaturation does not involve breaking of peptide bonds and does not describe protein formation.
Hence, statement (3) is incorrect.