A 5250 base-pair long plasmid with 10 negative supercoils would have a linking number of __________, considering 10.5 base pairs per turn for B DNA.
A 5250 base-pair long plasmid with 10 negative supercoils would have a linking number of __________, considering 10.5 base pairs per turn for B DNA.
Answer
Answer: 490
Explanation:
The linking number (Lk) of DNA is given by:
Lk = \frac{\text{Total base pairs}}{\text{Base pairs per turn}}
For a 5250 bp plasmid:
Lk_0 = \frac{5250}{10.5} = 500
With 10 negative supercoils:
Lk = Lk_0 - 10 = 500 - 10 = 490