Practice question

A linear molecule possesses two distinct termini. Each restriction cleavage introduces an additional break in the phosphodiester backbone. With one site, the molecule separates into two pieces; the second site cuts one of those pieces further. Under complete digestion every recognition sequence is hydrolyzed efficiently, so total fragments equal number of cuts plus one. For two sites this yields three fragments of sizes determined by inter-site distances. Circular DNA behaves differently, requiring equal numbers of cuts and fragments, but linearity dictates n+1 rule universally taught in NCERT genetics.