Question

The DNA double helix measures 0.34 nm/bp. The diameter of a nucleosome core particle is 11 nm. If the ratio of wrapped DNA length to nucleosome diameter is 4.51, the length of DNA around the nucleosome (to the nearest integer) is ...... bp.

Hint:

To calculate the length of DNA wrapped around a nucleosome, multiply the nucleosome diameter by the ratio of wrapped DNA length to nucleosome diameter, and divide by the length per base pair.

Answer 1

We are given:
- The DNA double helix measures \( 0.34 \, \text{nm/bp} \).
- The diameter of the nucleosome core particle is \( 11 \, \text{nm} \).
- The ratio of wrapped DNA length to nucleosome diameter is 4.51.

The wrapped DNA length around the nucleosome can be calculated by multiplying the nucleosome diameter by the ratio:
\[ \text{Wrapped DNA length} = 4.51 \times 11 = 49.61 \, \text{nm} \]
Now, to find the number of base pairs (bp) wrapped around the nucleosome, we divide the wrapped DNA length by the length of DNA per base pair:
\[ \text{Length of DNA} = \frac{49.61 \, \text{nm}}{0.34 \, \text{nm/bp}} = 146.5 \, \text{bp} \]
Rounding to the nearest integer, the length of DNA around the nucleosome is approximately:
\[ \boxed{146 \, \text{bp}} \]
Thus, the length of DNA wrapped around the nucleosome is 146 bp.