The base which is present in DNA but not in RNA is:
Show Hint
- Guanine
- Cytosine
- Thymine
- Adenine
The Correct Option is C
Solution and Explanation
Nucleic acids (DNA and RNA) are built from nucleotides containing specific nitrogenous bases.
Step 2: Meaning
There are purines (Adenine, Guanine) and pyrimidines (Cytosine, Thymine, Uracil).
Step 3: Analysis
Adenine (A), Guanine (G), and Cytosine (C) are present in both DNA and RNA molecules. The distinguishing nitrogenous base is the fourth base: DNA contains thymine (T), whereas RNA contains uracil (U).
• Nucleic acids are polymers composed of nucleotide units.
• Each nucleotide contains: itemize
• A pentose sugar.
• A phosphate group.
• A nitrogenous base.
Both DNA and RNA contain the purine bases: \[ \boxed{\text{Adenine (A) and Guanine (G)}}. \] Both nucleic acids also contain the pyrimidine base: \[ \boxed{\text{Cytosine (C)}}. \] The difference lies in the fourth nitrogenous base. DNA contains: \[ \boxed{\text{Thymine (T)}}. \] RNA does not contain thymine; instead, it contains: \[ \boxed{\text{Uracil (U)}}. \] Therefore, \[ \boxed{\text{DNA: A, G, C, T}} \] and \[ \boxed{\text{RNA: A, G, C, U}.} \] itemize
Step 4: Conclusion
Therefore, Thymine is the unique base found only in DNA.
Final Answer: (C)
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Top CBSE CLASS XII Nucleic Acids Questions
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