Multiple Choice
In the DNA double helix, which type of bond holds the two complementary strands together?
7. DNA and Chromosome Structure
DNA Structure
Multiple Choice
In the structure of DNA, which nitrogenous base forms complementary hydrogen bonds with thymine?
A
Guanine
B
Uracil
C
Cytosine
D
Adenine
Verified step by step guidance1
Recall that DNA is composed of four nitrogenous bases: adenine (A), thymine (T), guanine (G), and cytosine (C).
Understand that base pairing in DNA follows Chargaff's rules, where adenine pairs specifically with thymine, and guanine pairs with cytosine.
Recognize that the pairing occurs through hydrogen bonds: adenine forms two hydrogen bonds with thymine, stabilizing the DNA double helix.
Note that uracil is not found in DNA; it replaces thymine in RNA and pairs with adenine there.
Therefore, identify adenine as the nitrogenous base that forms complementary hydrogen bonds with thymine in DNA.
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