Multiple Choice
In the DNA double helix, what molecules form the sides of the “ladder” (the backbone)?
7. DNA and Chromosome Structure
DNA Structure
Multiple Choice
Which nitrogenous base is not found in DNA?
A
Uracil
B
Thymine
C
Adenine
D
Guanine
Verified step by step guidance1
Recall the four nitrogenous bases found in DNA: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
Understand that DNA and RNA differ in one of their nitrogenous bases; DNA contains Thymine, while RNA contains Uracil instead of Thymine.
Identify that Uracil is a nitrogenous base found only in RNA and not in DNA.
Compare the options given: Uracil, Thymine, Adenine, and Guanine, and recognize that Uracil is the base absent from DNA.
Conclude that the nitrogenous base not found in DNA is Uracil.
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