In a DNA molecule , if the number of phosphodiester bonds is 198, it has …..... bases .

Options

A. 150
B. 100
C. 300
D. 400

Answer

To solve the problem of determining the number of bases in a DNA molecule given the number of phosphodiester bonds, we can follow these steps:

### Step 1: Understand the relationship between phosphodiester bonds and bases
Phosphodiester bonds link nucleotides in a DNA strand. Each phosphodiester bond connects two nucleotides. If there are 'n' bases in a DNA molecule, the number of phosphodiester bonds is given by the formula:

\[ \text{Number of phosphodiester bonds} = n - 1 \]

This is because the first base does not require a bond to connect to a previous base.

### Step 2: Rearranging the formula
From the formula, we can rearrange it to find the number of bases (n):

\[ n = \text{Number of phosphodiester bonds} + 1 \]

### Step 3: Substitute the given value
In this case, we are given that the number of phosphodiester bonds is 198. We can substitute this value into the rearranged formula:

\[ n = 198 + 1 \]

### Step 4: Calculate the number of bases
Now, we perform the calculation:

\[ n = 199 \]

### Conclusion
Thus, the DNA molecule has **199 bases**.