If the distance between two consecutive base pairs is 0.34 nm then the length of DNA for a human diploid cell is

Options

A. (a) `6.6 xx 10^9 m`
B. (b) `6.6 x 10^9 bp` x `0.34 m`
C. (c) `2.2` metres
D. (d) `6.6 xx 10^-9 m`

Answer

To find the length of DNA for a human diploid cell given that the distance between two consecutive base pairs is 0.34 nm, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Given Data**:
- Distance between two consecutive base pairs = 0.34 nm
- Total number of base pairs in a haploid human genome = 3.3 billion base pairs

2. **Calculate the Total Number of Base Pairs in a Diploid Cell**:
- Since a diploid cell has two sets of chromosomes, we multiply the haploid number by 2:
\[ \text{Total base pairs in diploid cell} = 3.3 \text{ billion} \times 2 = 6.6 \text{ billion base pairs} \]
- In scientific notation, this is:
\[ 6.6 \text{ billion} = 6.6 \times 10^9 \text{ base pairs} \]

3. **Convert the Distance from Nanometers to Meters**:
- To convert nanometers to meters, we use the conversion factor:
\[ 1 \text{ nm} = 10^{-9} \text{ m} \]
- Therefore:
\[ 0.34 \text{ nm} = 0.34 \times 10^{-9} \text{ m} \]

4. **Calculate the Total Length of DNA**:
- The length of DNA can be calculated by multiplying the total number of base pairs by the distance between consecutive base pairs:
\[ \text{Length of DNA} = \text{Total base pairs} \times \text{Distance between base pairs} \]
- Substituting the values:
\[ \text{Length of DNA} = (6.6 \times 10^9) \times (0.34 \times 10^{-9}) \]

5. **Perform the Multiplication**:
- First, multiply the coefficients:
\[ 6.6 \times 0.34 = 2.244 \]
- Then, combine the powers of ten:
\[ 10^9 \times 10^{-9} = 10^0 = 1 \]
- Thus, the length of DNA in meters is:
\[ \text{Length of DNA} = 2.244 \text{ m} \]

6. **Final Answer**:
- The length of DNA for a human diploid cell is approximately **2.244 meters**. Rounding this to one decimal place gives us **2.2 meters**.