In tissue P systems several cells (elementary membranes) commu-
nicate through symport/antiport rules, thus carrying out a computation. We
add to such systems the basic feature of (cell) P systems with active membranes
{ the possibility to divide cells. As expected (as it is the case for P systems
with active membranes), in this way we get the possibility to solve computa-
tionally hard problems in polynomial time; we illustrate this possibility with
SAT problem.Ministerio de Ciencia y Tecnología TIC2002-04220-C03-0