Multiple Choice
In the DNA double helix, what type of interaction holds complementary nitrogenous bases together across the two strands?
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7. DNA and Chromosome Structure
DNA Structure
Multiple Choice
In double-stranded DNA, which base-pairing rule correctly describes Watson–Crick base pairing?
A
A pairs with C, and G pairs with T.
B
A pairs with T, and G pairs with C.
C
A pairs with G, and C pairs with T.
D
A pairs with U, and G pairs with C.
Verified step by step guidance1
Recall that Watson–Crick base pairing describes the specific hydrogen bonding between nitrogenous bases in double-stranded DNA.
Identify the four bases in DNA: Adenine (A), Thymine (T), Guanine (G), and Cytosine (C).
Understand that Adenine (A) pairs specifically with Thymine (T) through two hydrogen bonds, and Guanine (G) pairs with Cytosine (C) through three hydrogen bonds.
Note that Uracil (U) is not found in DNA but in RNA, so any pairing involving U is not correct for DNA base pairing rules.
Conclude that the correct Watson–Crick base pairing rule for double-stranded DNA is: \(A \leftrightarrow T\) and \(G \leftrightarrow C\).
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