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Multiple Choice
Which nitrogenous base is found in the nucleotides of DNA but not in RNA?
A
Cytosine
B
Thymine
C
Uracil
D
Adenine
Verified step by step guidance
1
Understand the structure of nucleotides in DNA and RNA. Both DNA and RNA are composed of nucleotides, which include a sugar, a phosphate group, and a nitrogenous base.
Identify the nitrogenous bases present in DNA. DNA contains four nitrogenous bases: adenine (A), guanine (G), cytosine (C), and thymine (T).
Identify the nitrogenous bases present in RNA. RNA contains adenine (A), guanine (G), cytosine (C), and uracil (U).
Compare the nitrogenous bases in DNA and RNA. Notice that thymine is present in DNA but is replaced by uracil in RNA.
Conclude that thymine is the nitrogenous base found in DNA but not in RNA, as uracil takes its place in RNA.