Question

The correct statements are :
A. Activation energy for enzyme catalysed hydrolysis of sucrose is lower than that of acid catalysed hydrolysis.
B. During denaturation, secondary and tertiary structures of a protein are destroyed but primary structure remains intact.
C. Nucleotides are joined together by glycosidic linkage between \( C_1 \) and \( C_4 \) carbons of the pentose sugar.
D. Quaternary structure of proteins represents overall folding of the polypeptide chain.
Choose the correct answer from the options given below :

• A. A, B and D Only
• B. A and B Only
• C. B and C Only
• D. A, C and D Only

Hint:

Remember: Primary structure = sequence of amino acids (peptide bonds); Tertiary structure = 3D shape of one chain; Quaternary = interaction between multiple chains.

Answer 1

The Correct Option is B

To determine the correct statements, let us analyze each option logically and scientifically: 

1. Statement A: "Activation energy for enzyme catalysed hydrolysis of sucrose is lower than that of acid catalysed hydrolysis."
   • Enzymes are biological catalysts that significantly lower the activation energy of a reaction, allowing it to proceed more efficiently at lower energy thresholds compared to an acid-catalysed reaction.
   • This makes Statement A true.
2. Statement B: "During denaturation, secondary and tertiary structures of a protein are destroyed but primary structure remains intact."
   • Denaturation disrupts the secondary and tertiary structures by breaking non-covalent interactions like hydrogen bonds, ionic bonds, and disulfide bridges, but the primary structure (amino acid sequence) remains unaltered.
   • Thus, Statement B is also true.
3. Statement C: "Nucleotides are joined together by glycosidic linkage between \(C_1\) and \(C_4\) carbons of the pentose sugar."
   • Nucleotides in nucleic acids are connected by phosphodiester bonds between the 5' phosphate group of one nucleotide and the 3' hydroxyl group of the next, not by glycosidic linkages between carbon atoms of sugars.
   • Therefore, Statement C is false.
4. Statement D: "Quaternary structure of proteins represents overall folding of the polypeptide chain."
   • The quaternary structure refers to the assembly of multiple polypeptide subunits into a larger functional protein complex, not just the folding of a single polypeptide chain.
   • Thus, Statement D is false because it mistakenly describes tertiary structure.

Based on the analysis, the correct statements are A and B. Hence, the correct answer is A and B Only.