If there are `10,000` nitrogenous base pairs in a DNA then how many nucleotides are there-

Options

A. 500
B. `10,000`
C. `20,000`
D. `40,000`

Answer

To determine the number of nucleotides in a DNA molecule given that there are 10,000 nitrogenous base pairs, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Base Pairs**:
- In DNA, a base pair consists of two complementary nitrogenous bases. These bases are paired as follows: adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C).

2. **Identify the Relationship Between Base Pairs and Nucleotides**:
- Each base pair is made up of two nucleotides. Therefore, for every base pair, there are two nucleotides involved.

3. **Calculate the Total Number of Nucleotides**:
- Given that there are 10,000 base pairs, we can calculate the total number of nucleotides by multiplying the number of base pairs by 2 (since each base pair consists of 2 nucleotides).
- Total nucleotides = Number of base pairs × 2
- Total nucleotides = 10,000 × 2 = 20,000

4. **Conclusion**:
- Therefore, if there are 10,000 nitrogenous base pairs in DNA, there are a total of 20,000 nucleotides.

### Final Answer:
- The number of nucleotides is **20,000**.