A plasmid DNA and a linear DNA, both of the same size (10 kb), have one site for a restriction endonuclease. The restriction site in linear DNA is at 5 kb distance from one end. When cut and separated on agarose gel electrophoresis, how many bands will be obtained in case of plasmid and linear DNA respectively, assuming complete digestion?

A plasmid DNA and a linear DNA, both of the same size (10 kb), have one site for a restriction endonuclease. The restriction site in linear DNA is at 5 kb distance from one end. When cut and separated on agarose gel electrophoresis, how many bands will be obtained in case of plasmid and linear DNA respectively, assuming complete digestion.

Plasmid is a closed circular DNA. One cut opens the circle and thus only one fragment is formed.Thus only one band appears in electrophoresis.

Linear DNA,one cut gives two fragments but of equal size.

since agarose gel electrophoresis is a size based separation technique ,only one band is obtained.