Question

Assertion ( A): Thymine pairs with adenine
whereas cytosine pairs with Guanine in DNA
molecule .
Reason ( R ):The hydrogen bonding between
bases of two strands is Highly specific .

• 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 a correct explanation of A
• C. A is true but R is false
• D. .A is false but R is true

Answer 1

The correct option is C A is true but R is false

Thymine pairs with adenine whereas cytosine pairs with Guanine in DNA molecule. The nucleotides are joined to one another in a chain by covalent bonds between the sugar of one nucleotide and the phosphate of the next, resulting in an alternating sugar-phosphate backbone. According to base pairing rules (A with T and C with G), hydrogen bonds bind the nitrogenous bases of the two separate polynucleotide strands to make double-stranded DNA.