Scientists are studying the structure and function of receptor x, a single-polypeptide protein that is found in the membrane around certain types of cells. receptor x contains no alpha-helices or beta sheets. a specific molecule outside the cells is recognized and bound by receptor x. the binding of the molecule to receptor x causes the cells to have a particular response.

answer; a male inherits only one allele of the x-linked gene controlling hair color;

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.

cell division is not regulated in tumor cells.