AP BIOLOGY

Detailed explanation-1: -The gel consists of a permeable matrix, a bit like a sieve, through which molecules can travel when an electric current is passed across it. Smaller molecules migrate through the gel more quickly and therefore travel further than larger fragments that migrate more slowly and therefore will travel a shorter distance.

Detailed explanation-2: -DNA fragments are negatively charged, so they move towards the positive electrode. Because all DNA fragments have the same amount of charge per mass, small fragments move through the gel faster than large ones.

Detailed explanation-3: -Shorter DNA segments find more pores that they can wiggle through, longer DNA segments need to do more squeezing and up or down moving. For this reason, shorter DNA segments move through their lane at a faster rate than longer DNA segments.

Detailed explanation-4: -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.

Detailed explanation-5: -In agarose, the migration rate of fragments of DNA is inversely proportional to their size: the smaller the DNA molecule, the faster it migrates through the gel. The sieving property influences the rate at which a molecule migrates.