The electronic spectrum of sheets of graphite (plane honeycomb lattice) folded into regular polyhedra is studied. A continuum limit valid for sufficiently large molecules and based on the tight-binding approximation is derived. It is found that a Dirac equation describes the flat graphite lattice. Curving the lattice by insertion of odd-numbered rings can be mimicked by coupling effective gauge fields. In particular the C60 and related molecules are well described by the Dirac equation on the surface of a sphere coupled to a color monopole sitting at its center.M.A.H.V. thanks the department of Física Teórica of the Universidad Autónoma of Madrid for financial support during the course of this work. This work has been partially supported by the CICyT (Spain).Peer reviewed