If a restriction enzyme is used to digest both a closed circular DNA plasmid and a linear DNA strand with five recognition sites each, how many fragments will be produced in total?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) -11
To determine the number of fragments produced when a restriction enzyme digests a circular DNA molecule and a linear DNA molecule, we need to consider the number of recognition sites and the type of DNA molecule.
Circular DNA Molecule:
For a closed circular DNA molecule with 5 recognition sites:
- Each cut made by the restriction enzyme will break the circle, creating a fragment.
- Since it is circular, cutting it at 5 sites will produce 5 fragments.
Linear DNA Molecule:
For a linear DNA molecule with 5 recognition sites:
- Each cut will produce a new fragment, but since the DNA is linear, the first cut divides it into 2 pieces, and each subsequent cut adds one more piece.
- Cutting it at 5 sites will produce 6 fragments.
Total Number of Fragments:
- From the circular DNA: 5 fragments
- From the linear DNA: 6 fragments
Thus, the total number of fragments generated will be:
5 (from circular DNA)+6 (from linear DNA)=11