SSC MTS EXAM

Detailed explanation-1: -Under normal circumstances, the nitrogen-containing bases adenine (A) and thymine (T) pair together, and cytosine (C) and guanine (G) pair together. The binding of these base pairs forms the structure of DNA .

Detailed explanation-2: -Reason: Adenine specifically forms hydrogen bonds with guanine whereas cytosine forms hydrogen bonds with thymine.

Detailed explanation-3: -The bonds between Adenine and Thymine create a similar shape as guanine and cytosine to accommodate the diameter of 2nm which is the pitch of the helix. Purines can’t combine with other purines due to double-ring structures. The higher the bond specificity higher the stability and the bond will be stronger.

Detailed explanation-4: -This is known as a complementary base pairing. The purines form hydrogen bonds with pyrimidines, in which adenine bonds only to thymine in two hydrogen bonds, and cytosine bonds only to the guanine in three hydrogen bonds.