Select true of false statement :
The pitch of the DNA helix is 3.4 nm.

Answer

To determine whether the statement "The pitch of the DNA helix is 3.4 nm" is true or false, we can follow these steps:

### Step 1: Understand the Structure of DNA
DNA is structured as a double helix, which consists of two strands that wrap around each other. The basic units of DNA are nucleotides, which pair to form base pairs.

**Hint:** Recall that DNA is a double-stranded molecule with a helical structure.

### Step 2: Define Pitch of the DNA Helix
The pitch of the DNA helix refers to the distance it takes for the helix to make one complete turn. This distance is measured along the axis of the helix.

**Hint:** The pitch is related to how many base pairs are present in one full turn of the helix.

### Step 3: Identify the Number of Base Pairs in One Turn
In a typical DNA molecule, there are approximately 10 base pairs per complete turn of the helix.

**Hint:** Think about how many base pairs contribute to the overall structure of the DNA helix.

### Step 4: Calculate the Pitch
The distance between each base pair is about 0.34 nm. Therefore, for 10 base pairs, the pitch can be calculated as:
\[ \text{Pitch} = \text{Number of base pairs} \times \text{Distance between base pairs} \]
\[ \text{Pitch} = 10 \times 0.34 \, \text{nm} = 3.4 \, \text{nm} \]

**Hint:** Use multiplication to find the total distance for the 10 base pairs.

### Step 5: Evaluate the Statement
Since we calculated the pitch of the DNA helix to be 3.4 nm, we can conclude that the statement "The pitch of the DNA helix is 3.4 nm" is true.

**Hint:** Compare your calculation with the statement to see if they match.

### Final Answer
The statement is **True**. The pitch of the DNA helix is indeed 3.4 nm.