How many total types of N-bases in DNA and RNA molecules -

Options

A. 4
B. 3
C. 5
D. 6

Answer

To determine the total types of nitrogenous bases (N-bases) in DNA and RNA molecules, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the N-bases in DNA**:
- DNA contains four types of nitrogenous bases:
- Adenine (A)
- Guanine (G)
- Cytosine (C)
- Thymine (T)

2. **Identify the N-bases in RNA**:
- RNA also contains four types of nitrogenous bases:
- Adenine (A)
- Guanine (G)
- Cytosine (C)
- Uracil (U) (instead of Thymine)

3. **Count the unique N-bases**:
- The bases present in both DNA and RNA are Adenine, Guanine, and Cytosine.
- The unique bases are:
- From DNA: Thymine (T)
- From RNA: Uracil (U)

4. **Total unique N-bases**:
- Combining the bases from both DNA and RNA, we have:
- Adenine (A)
- Guanine (G)
- Cytosine (C)
- Thymine (T) (only in DNA)
- Uracil (U) (only in RNA)

5. **Conclusion**:
- Therefore, the total number of unique nitrogenous bases in DNA and RNA is 5.

### Final Answer:
There are a total of 5 types of nitrogenous bases found in DNA and RNA molecules.

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