Biochemistry

The given question presents two statements regarding peptides and proteins, and we need to evaluate their correctness based on our understanding of chemistry. Let's examine each statement:

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 chains of amino acids, typically containing 2 to 20 amino acid residues. Upon hydrolysis, they release the amino acids from which they are constituted. Both oligopeptides and proteins, when fully hydrolyzed, yield \alpha -amino acids, not \beta -amino acids. \beta -amino acids are seldom involved in the structure of natural proteins and peptides.
   • Conclusion: This statement is incorrect because both oligopeptides and proteins give rise to \alpha -amino acids upon hydrolysis.
2. Statement (II): "Natural proteins are denatured by acids which convert the water-soluble form of fibrous proteins to their water-insoluble form."
   • Explanation: Denaturation of proteins is a process where proteins lose their native structure and bioactivity due to external stress or compounds, leading to the unfolding of their three-dimensional structure. Acids can indeed cause denaturation. However, the focus of the statement on fibrous proteins becoming water-insoluble is misleading. Generally, denaturation by acids makes proteins less soluble in water, not specifically tailored to fibrous proteins. In fact, fibrous proteins (e.g., collagen, keratin) are typically already insoluble in water due to their structural characteristics.
   • Conclusion: This statement is misleading and incorrect because it overgeneralizes the effect of acids specifically on fibrous proteins regarding solubility.

Given the evaluations above, both Statement I and Statement II are incorrect. Therefore, the correct answer is: Both statement I and statement II are incorrect.