Which type of bonds hold complementary base pairs together in DNA?

Which type of bonds hold complementary base pairs together in DNA?

• A. Hydrogen bonds
• B. Ionic bonds
• C. Covalent bonds
• D. Peptide bonds

Answer: (A)

Hydrogen bonds hold complementary base pairs together in DNA. These are the weak, noncovalent attractions that form between specific pairs: adenine pairs with thymine using two hydrogen bonds, and guanine pairs with cytosine using three hydrogen bonds. This bonding type is strong enough to keep the two strands aligned, yet weak enough to allow the strands to separate during replication and transcription. In contrast, covalent bonds connect atoms within each strand’s backbone, and peptide bonds link amino acids in proteins; ionic bonds don’t mediate base pairing.

Hydrogen bonds hold complementary base pairs together in DNA. These are the weak, noncovalent attractions that form between specific pairs: adenine pairs with thymine using two hydrogen bonds, and guanine pairs with cytosine using three hydrogen bonds. This bonding type is strong enough to keep the two strands aligned, yet weak enough to allow the strands to separate during replication and transcription. In contrast, covalent bonds connect atoms within each strand’s backbone, and peptide bonds link amino acids in proteins; ionic bonds don’t mediate base pairing.