In the spiral staircase model of DNA, the rungs are
A) deoxyribose sugars.
B) hydrogen bonds.
C) nucleotide base pairs.
D) phosphate groups.
E) composed of all of these.

Question

Quizplus · Accepted Answer

The rungs of the spiral staircase model of DNA are nucleotide base pairs. Each rung is composed of two nitrogenous bases that are held together by hydrogen bonds. The sugar-phosphate backbone of the DNA molecule forms the sides or rails of the staircase. Deoxyribose sugars and phosphate groups make up this backbone. Therefore, choice (C) is the best answer as it correctly identifies the rungs of the DNA molecule.

In the Spiral Staircase Model of DNA, the Rungs Are