LIFE SCIENCE

Detailed explanation-1: -The sieving effect causes DNA fragments to move across an agarose gel according to their size during gel electrophoresis. The smallest fragments travel the most distance. DNA is a negatively charged molecule and it will migrate to the positively charged electrode when an electric current is supplied to the gel.

Detailed explanation-2: -Supercoiled plasmid DNA, because of its compact conformation, moves through the gel fastest, followed by a linear DNA fragment of the same size, with the open circular form traveling the slowest.

Detailed explanation-3: -Because all DNA fragments have the same amount of charge per mass, small fragments move through the gel faster than large ones.

Detailed explanation-4: -The molecules travel through the pores in the gel at a speed that is inversely related to their lengths. This means that a small DNA molecule will travel a greater distance through the gel than will a larger DNA molecule.

Detailed explanation-5: -The rate of migration of a DNA molecule through a gel is determined by the following: 1) size of DNA molecule; 2) agarose concentration; 3) DNA conformation(5); 4) voltage applied, 5) presence of ethidium bromide, 6) type of agarose and 7) electrophoresis buffer.