An electron has no internal configuration that we know of and is considered as one of the fundamental particles. Protons and neutrons, on the other hand are made up of smaller fundamental particles calledquarks. There are 6 different types or"flavours" of quarks: up, down, charm, strange, bottom and top. Neutrons and protons are made up of only up and down quarks. Unlike neutrons, protons and electronsquarks may have fraction charge.The pricipile of quantization of charge is still followed because quarks are the only particles which have fractional charges and they always occur in combination. A neutron is made up of 1 up quark(charge = +2/3) and 2 down quarks(charge = -1/3). Similarly, a proton is made up of 2 up and 1 down quark.