  We determine nuclear structure functions and quark distributions for $^7$Li,
$^{11}$B, $^{15}$N and $^{27}$Al. For the nucleon bound state we solve the
covariant quark-diquark equations in a confining Nambu--Jona-Lasinio model,
which yields excellent results for the free nucleon structure functions. The
nucleus is described using a relativistic shell model, including mean scalar
and vector fields that couple to the quarks in the nucleon. The nuclear
structure functions are then obtained as a convolution of the structure
function of the bound nucleon with the light-cone nucleon distributions. We
find that we are readily able to reproduce the EMC effect in finite nuclei and
confirm earlier nuclear matter studies that found a large polarized EMC effect.
