  A formalism is proposed to study the electronic and transport properties of
graphene sheets with corrugations as the one recently synthesized. The
formalism is based on coupling the Dirac equation that models the low energy
electronic excitations of clean flat graphene samples to a curved space. A
cosmic string analogy allows to treat an arbitrary number of topological
defects located at arbitrary positions on the graphene plane. The usual defects
that will always be present in any graphene sample as pentagon-heptagon pairs
and Stone-Wales defects are studied as an example. The local density of states
around the defects acquires characteristic modulations that could be observed
in scanning tunnel and transmission electron microscopy.
