Question

Chargaff's rule is applicable to

• A. Single-stranded DNA
• B. Single-stranded RNA
• C. Double-stranded DNA
• D. Double-stranded RNA

Answer 1

The correct option is C

Double-stranded DNA

The Correct option is C.

Explanation of the correct option:

1. Chargaff’s rules are based on complementary base pairing between nitrogenous bases of two antiparallel strands of a double-stranded DNA molecule and thus are applicable to double-stranded DNA only.
2. According to Chargaff’s rule, all cellular DNAs, regardless of the species, the number of adenosine residues is equal to the number of thymidine residues which means that A = T and the number of guanosine residues is equal to the number of cytidine residues; G = C.
3. Hence, the sum of the purine residues equals the sum of the pyrimidine residues; i.e., A + G = T + C;

Final answer: Chargaff's rule is applicable to double-stranded DNA.