Question

The correct statements are:

• Activation energy for enzyme catalysed hydrolysis of sucrose is lower than that of acid catalysed hydrolysis.
• During denaturation, secondary and tertiary structures of a protein are destroyed but primary structure remains intact.
• Nucleotides are joined together by glycosidic linkage between \( C_1 \) and \( C_4 \) carbons of the pentose sugar.
• Quaternary structure of proteins represents overall folding of the polypeptide chain.

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

Hint:

Important facts:

• Enzymes decrease activation energy.
• Denaturation does not break peptide bonds.
• DNA nucleotides are linked by phosphodiester linkage.
• Tertiary structure represents overall folding of a chain.

Answer 1

The Correct Option is C

Concept: Proteins and nucleic acids possess different structural levels and bonding patterns.

• Enzymes lower activation energy.
• Denaturation destroys higher structures of proteins.
• Nucleotides are linked by phosphodiester bonds.
• Quaternary structure refers to association of multiple polypeptide chains.

Step 1: Check statement A Enzymes act as catalysts and lower the activation energy of reactions. Hence enzyme catalysed hydrolysis has lower activation energy. Statement A is correct.

Step 2: Check statement B Denaturation destroys secondary and tertiary structures but peptide bonds remain intact. Thus primary structure remains unchanged. Statement B is correct.

Step 3: Check statement C Nucleotides are connected through \(3'-5'\) phosphodiester linkage and not glycosidic linkage. Hence statement C is incorrect.

Step 4: Check statement D Overall folding of a single polypeptide chain represents tertiary structure. Quaternary structure involves arrangement of multiple chains. Hence statement D is incorrect. Therefore, statements A and B only are correct.