Question

12. Assertion: The two strands arecomplementary to each other
Reason: The hydrogen bonds areformed between specific pairs of bases.​

Answer 1

The complete question is:-

Assertion (A): The two strands are complementary to each other

Reason (R): The hydrogen bonds are formed between specific pairs of bases.​

(a) Both A and R are true and R is the correct explanation of A.

(b) Both A and R are true but R is not the correct explanation of A.

(c) A is true but R is false.

(d) A is false but R is true.

Answer:-

Both assertion and reason are correct and reason is the correct explanation of assertion.

• DNA (Deoxyribose Nucleic Acid) has a double-helical structure in which the two strands are complementary to each other.  
• It is because base-pairing exists between them.
• Adenine of one strand is linked to the thymine on the other by two hydrogen bonds while guanine is linked to cytosine by three hydrogen bonds.