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Multiple Choice
Which of the following nitrogenous bases is found in DNA nucleotides but not in RNA?
A
Cytosine
B
Uracil
C
Adenine
D
Thymine
Verified step by step guidance
1
Understand the structure of nucleotides: Nucleotides are the building blocks of nucleic acids (DNA and RNA) and consist of a sugar, a phosphate group, and a nitrogenous base.
Identify the nitrogenous bases in DNA: DNA contains four nitrogenous bases: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
Identify the nitrogenous bases in RNA: RNA contains four nitrogenous bases as well, but instead of Thymine, it contains Uracil (U). Therefore, RNA has Adenine (A), Uracil (U), Cytosine (C), and Guanine (G).
Compare the bases in DNA and RNA: Notice that Thymine is present in DNA but is replaced by Uracil in RNA.
Conclude which base is unique to DNA: Since Thymine is found in DNA but not in RNA, it is the nitrogenous base that is unique to DNA nucleotides.