In the base pairing within a DNA double helix,
A) purines pair with purines.
B) A pairs with U and G pairs with C.
C) A pairs with G and C pairs with T.
D) A pairs with T and G pairs with C.

Question

Quizplus · Accepted Answer

In DNA base pairing, A always pairs with T (adenine with thymine) and G always pairs with C (guanine with cytosine). This is known as complementary base pairing. Purines (adenine and guanine) always pair with pyrimidines (thymine and cytosine). Choice A is incorrect as purines do not pair with purines. Choice B is incorrect as A always pairs with T, not U. Choice C is incorrect as A does not pair with G.

In the Base Pairing Within a DNA Double Helix