Hemophilia is caused by a defect in the genes responsible for the formation of blood clotting factors viii and ix. These genes are located on the X chromosome. A female has two X chromosomes and a male has an X chromosome and a Y chromosome. Therefore, all the daughters of a hemophiliac father will be the carriers of this disease, and half of his sons acquiring the X chromosome from the father will have the disease.
It would of course be ATP (Adenosine Tri Phosphate) the main source of energy for most cells.
