Question

The purines and pyrimidines found in DNA pair in a precise manner, leading us to the concept of complementarity or base complementation. Which of the following is accurate with respect to the pairing relationships?

a. cytosine with uracil and thymine with guanine
b. thymine with uracil and cytosine with adenine
c. adenine with guanine andthymine with cytosine
d. thymine with adenine and cytosine with guanine
e. purine with purine and pyrimidine with pyrimidine

Answer 1

In DNA, adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G), following the base complementarity principle and maintaining the DNA's double helix structure through hydrogen bonds.

Step-by-step explanation:

The correct pairing relationships in DNA, which adhere to the concept of base complementarity, are that adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G). This pairing is due to hydrogen bonding that occurs only between a specific purine and a specific pyrimidine, ensuring the integrity and uniform width of the DNA double helix. Adenine and thymine form two hydrogen bonds between them, whereas cytosine and guanine form three hydrogen bonds.