Question

Given below are two statements :
Statement (I) : On hydrolysis, oligo peptides give rise to fewer number of $ \alpha $-amino acids while proteins give rise to a large number of $ \beta $-amino acids.
Statement (II) : Natural proteins are denatured by acids which convert the water soluble form of fibrous proteins to their water insoluble form.
In the light of the above statements, choose the most appropriate answer from the options given below :

• A. Both statement I and statement II are correct
• B. Statement I is incorrect but Statement II is correct
• C. Both statement I and statement II are incorrect
• D. Statement I is correct but Statement II is incorrect

Hint:

Remember the basic structure of \( \alpha \)- and \( \beta \)-amino acids and the type of amino acids produced upon protein and peptide hydrolysis. Also, understand the process of protein denaturation and its effects on protein structure and solubility, keeping in mind the different types of proteins (globular and fibrous).

Answer 1

The Correct Option is C

The provided question contains two assertions about peptides and proteins, which will be assessed for chemical accuracy. Each assertion is examined below:

1. Statement (I): "On hydrolysis, oligopeptides give rise to fewer number of \alpha-amino acids while proteins give rise to a large number of \beta-amino acids."
   • Explanation: Oligopeptides are short amino acid chains (2-20 residues). Hydrolysis breaks them down into their constituent amino acids. Both oligopeptides and proteins, upon complete hydrolysis, yield \alpha-amino acids, not \beta-amino acids. \beta-amino acids are rarely found in natural proteins and peptides.
   • Conclusion: This statement is false, as hydrolysis of both oligopeptides and proteins yields \alpha-amino acids.
2. Statement (II): "Natural proteins are denatured by acids which convert the water-soluble form of fibrous proteins to their water-insoluble form."
   • Explanation: Protein denaturation is the loss of native structure and bioactivity due to external factors, causing unfolding. Acids can denature proteins. However, the statement's emphasis on fibrous proteins becoming water-insoluble is inaccurate. Denaturation by acids generally reduces protein water solubility, but fibrous proteins (e.g., collagen, keratin) are typically already water-insoluble due to their structure.
   • Conclusion: This statement is misleading and false because it inaccurately generalizes the effect of acids on fibrous protein solubility.

Based on the above assessments, both Statement I and Statement II are incorrect. Therefore, the correct answer is: Both statement I and statement II are incorrect.