You will instead find that you are holding quark stuck to an antiquark to form a meson. In this way the quark groupings of two or three are always preserved. It is possible to rearrange the groups but not to completely free an isolated quark from its associates. The strong force binds groups of quarks together, but it cannot change one flavor of quark to another. This flavor-changing can, however, be done by the weak force.
Leptons are the light particles of the weak interaction.
The GUTS theories go a step beyond the quark model by matching up the six leptons of the weak interaction with the six quark flavors of the strong interaction. The assertion of GUTS is that leptons and quarks are the same kind of objects, obeying similar general rules and which under some circumstances can be converted into one another. The leptons are cousins of the quarks, but there are differences. There are no leptons with fractional charge but only charge one or zero. Figure 1 shows the family album of the quark clan and their lepton cousins.