Question
DNA is made up of pairs of nitrogenous bases. Which of the following nitrogenous bases is paired correctly? A. Guanine-guanine B. Cytosine-thymine C. Thymine-adenine D. Adenine-guanine
Answer
4.5
(270 Votes)
Llinos
Master · Tutor for 5 years
Answer
C
Explanation
DNA, deoxyribonucleic acid, is the primary molecule of life. It is composed of nucleotides that include a phosphate group, a sugar molecule, and a nitrogenous base. The nitrogenous bases essentially serve as the code for constructing proteins, which cells use for everything. In the structure of DNA, these nitrogenous bases form complementary pairs with bases on the opposing DNA strand, creating the unique double-helix structure of the DNA molecule. The base pairing in DNA involves adenine (A) to thymine (T) while cytosine (C) pairs with Guanine (G). Probing the given options, option C, Thymine-Adenine, adopts this correct base pairing mode in DNA, whereas others appear inappropriately paired. The other options describe pairings that do not occur naturally in DNA: guanine can't pair with guanine, as complementarily requires heterologous pairs, adenine wouldn't pair with guanine, and cytosine wouldn't naturally pair with thymine. These improper pairs wouldn’t provide stable DNA molecular structure or usable genetic codes.