Laser light is used to manipulate Bose Einstein Condensates (BEC) as well as degenerate Fermi gases. Static and dynamic properties are studied when a periodic 1D potential is created. Nonlinear interactions break the stability of the BEC while for the Fermi gas Bloch oscillations are observed for long time intervals. Results are discussed also in connection with the possible measurement of forces at short distances using trapped atoms "Bloch oscillators". Recent observations on the properties of a BEC in optical lattices with large spacing and in disordered potentials produced by optical speckle patterns are also addressed. Quantum interference after expansion and measured modifications of the collective dynamics are discussed also in connection with the phenomenology of BEC in microtraps.