Question

Chemical bonds cut by restriction endonucleases:

• A. Hydrogen bonds
• B. Glycosidic bonds
• C. Phosphodiester bonds
• D. Peptide bonds

Hint:

Restriction enzymes belong to the class of enzymes called {Nucleases}.

Answer 1

The Correct Option is C

Step 1: Understanding Restriction Enzymes:
Restriction endonucleases are molecular scissors that cut DNA at specific recognition sites.
Step 2: Mechanism of Action:
DNA strands are made of nucleotides linked by a sugar-phosphate backbone. The bond connecting the sugar of one nucleotide to the phosphate of the next is the phosphodiester bond. Restriction enzymes catalyze the hydrolysis of this specific bond to break the DNA backbone. (Note: While sticky ends involve breaking hydrogen bonds between bases effectively separating the strands, the enzymatic \cutting action is on the phosphodiester backbone).
Step 3: Evaluating Options:
(A) Hydrogen bonds: Connect base pairs; broken by helicase or heat.
(B) Glycosidic bonds: Connect base to sugar.
(C) Phosphodiester bonds: Connect nucleotides in the strand; cut by endonucleases.
(D) Peptide bonds: Connect amino acids in proteins.
Step 4: Final Answer:
The correct option is (C).