Multiple Choice
In the DNA double helix, what type of interaction primarily holds complementary nitrogenous bases together across the two strands?
7. DNA and Chromosome Structure
DNA Structure
Multiple Choice
Which set correctly lists the four nucleotides found in DNA?
A
Adenine, thymine, cytosine, and guanine
B
Adenine, thymine, guanine, and ribose
C
Adenine, thymine, cytosine, and uracil
D
Adenine, uracil, cytosine, and guanine
Verified step by step guidance1
Recall that DNA is composed of four nitrogenous bases, which are the fundamental units of the genetic code.
Identify the two purines in DNA: adenine (A) and guanine (G), which have a double-ring structure.
Identify the two pyrimidines in DNA: cytosine (C) and thymine (T), which have a single-ring structure.
Note that uracil (U) is found in RNA, not DNA, and ribose is a sugar, not a nucleotide base.
Therefore, the correct set of nucleotides in DNA is adenine, thymine, cytosine, and guanine.
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