Which base pairs with Guanine in Watson-Crick base pairing?

Which base pairs with Guanine in Watson-Crick base pairing?

• A. Cytosine
• B. Adenine
• C. Uracil
• D. Thymine

Answer: (A)

In Watson-Cick base pairing, complementary bases pair through specific hydrogen-bonding patterns to keep the DNA or RNA double helix uniform in width. Guanine pairs with Cytosine because they form three hydrogen bonds between them and have compatible shapes and functional groups that align perfectly, giving a particularly stable G–C interaction. This one-to-one pairing with three bonds also helps explain why GC-rich regions are more thermally stable than AT (or AU) regions. The other bases don’t form the canonical pairing with Guanine: Adenine pairs with Thymine in DNA (or Uracil in RNA), using two hydrogen bonds, while Uracil pairs with Adenine in RNA.

In Watson-Cick base pairing, complementary bases pair through specific hydrogen-bonding patterns to keep the DNA or RNA double helix uniform in width. Guanine pairs with Cytosine because they form three hydrogen bonds between them and have compatible shapes and functional groups that align perfectly, giving a particularly stable G–C interaction. This one-to-one pairing with three bonds also helps explain why GC-rich regions are more thermally stable than AT (or AU) regions. The other bases don’t form the canonical pairing with Guanine: Adenine pairs with Thymine in DNA (or Uracil in RNA), using two hydrogen bonds, while Uracil pairs with Adenine in RNA.