Which of the following best explains the movement of DNA during gel electrophoresis? A. Since restriction enzymes cut DNA into differently sized pieces, polymerase is able to move the fragments through the gel.
B. Since polymerase enzymes cut DNA into differently sized pieces, restriction enzymes are able to move the fragments through the gel.
C. Since DNA is positively charged it attracts toward the negative end of the gel plate.
D. Since DNA is negatively charged it attracts toward the positive end of the gel plate.

An  atom  (ours, not carroll's) consists of a positively charged  nucleus, surrounded by one or more negatively charged particles called  electrons. the positive charges equal the negative charges, so the atom has no overall charge; it is electrically neutral. most of an atom's mass is in its nucleus; the mass of an electron is only 1/1836 the mass of the lightest nucleus, that of hydrogen. although the nucleus is heavy, it is quite small compared with the overall size of an atom. the radius of a typical atom is around 0.1 to 0.25 nanometres (nm), whereas the radius of a nucleus is about 10-6  nm.  *  if an atom were enlarged to the size of the earth, its nucleus would be only 200 feet in diameter and could easily rest inside a small football stadium.read more on -