$\bullet$ Cyclic photophosphorylation involves only PS I. Cyclic photophosphorylation is a process in which an electron expelled by the excited photocentre is returned to it after passing through a series of electron carriers. The excited electron does not pass on to NADP⁺ but is cycled back to the PS I complex through the electron transport chain.
Non-cyclic photophosphorylation involves both photosystems I and II. The electron follows a non-cyclic pathway in it. The representation of it is also called Z scheme.

$\bullet$ Both PS I and PS II are found on grana lamellae whereas stroma lamellae have PS I only and lack NADP reductase.