Question

Which of the pair is common among both DNA and RNA?

• A. Cytosine and Thymine
• B. Cytosine and Uracil
• C. Adenine and Guanine
• D. Adenine and Thymine

Hint:

DNA and RNA both contain Adenine, Guanine, and Cytosine. DNA contains Thymine, while RNA contains Uracil.

Answer 1

The Correct Option is C

Concept:
DNA and RNA are nucleic acids. Both are made up of nitrogenous bases, sugar, and phosphate groups. The nitrogenous bases present in DNA and RNA are partly similar and partly different.

Step 1: Write the nitrogenous bases present in DNA.
DNA contains four nitrogenous bases: \[ \text{Adenine (A), Guanine (G), Cytosine (C), Thymine (T)} \]

Step 2: Write the nitrogenous bases present in RNA.
RNA contains four nitrogenous bases: \[ \text{Adenine (A), Guanine (G), Cytosine (C), Uracil (U)} \]

Step 3: Compare DNA and RNA bases.
Common bases in both DNA and RNA are: \[ \text{Adenine, Guanine, Cytosine} \] DNA has thymine, while RNA has uracil instead of thymine.

Step 4: Check the given pairs.
Option (A): Cytosine and Thymine. Thymine is not present in RNA. So this is incorrect.
Option (B): Cytosine and Uracil. Uracil is not present in DNA. So this is incorrect.
Option (C): Adenine and Guanine. Both are present in DNA and RNA. So this is correct.
Option (D): Adenine and Thymine. Thymine is not present in RNA. So this is incorrect. \[ \therefore \text{Correct Answer is (C)} \]