NEETZoologyBiotechnology - Principles and Processes
A linear DNA molecule of 5 kb is fully digested with a restriction endonuclease that has two recognition sites located at 1 kb and 3 kb from one end. The digested DNA is then subjected to agarose gel electrophoresis. Determine the total number of visible bands on the gel and identify the size of the fragment that will be found closest to the anode.
Options
- A3 bands, with the 1 kb fragment closest to the anode
- B3 bands, with the 2 kb fragment closest to the anode
- C2 bands, with the 1 kb fragment closest to the anode
- D2 bands, with the 2 kb fragment closest to the anode
Correct answer
C. 2 bands, with the 1 kb fragment closest to the anode
Step-by-step solution
A linear DNA molecule of 5 kb with restriction sites at 1 kb and 3 kb from one end will be cleaved into three fragments. The sizes of these fragments are 1 kb (from 0 to 1 kb ), 2 kb (from 1 kb to 3 kb ), and 2 kb (from 3 kb to 5 kb ). During agarose gel electrophoresis, DNA fragments separate based on their size. The two 2 kb fragments have the same size and will co-migrate, appearing as a single band on the gel. The 1 kb fragment will form a second band. Therefore, a total of 2 visible bands will be observed. Sma