How many steps are involved in one complete turn of B-DNA?

Answer

To determine how many steps are involved in one complete turn of B-DNA, we can follow these steps:

### Step 1: Understand B-DNA Structure
B-DNA is the most common form of DNA found in biological systems. It has a double helix structure with a specific diameter and distance between base pairs.

### Step 2: Identify the Diameter
The diameter of B-DNA is approximately 20 Ångströms (Å). This measurement helps us visualize the overall structure of the DNA.

### Step 3: Measure the Distance Between Base Pairs
The distance between each base pair in B-DNA is about 3.4 Å. This distance is crucial for calculating the number of base pairs in one complete turn.

### Step 4: Define a Complete Turn
A complete turn of B-DNA refers to the full helical twist of the DNA structure. This includes both the minor and major grooves.

### Step 5: Calculate the Number of Base Pairs in One Turn
In one complete turn of B-DNA, there are typically 10 base pairs. This means that as the DNA twists, it makes 10 distinct steps or pairs of bases.

### Conclusion
Therefore, the number of steps involved in one complete turn of B-DNA is **10 steps**.

---