The pump module has a pump channel that is connected to a valve chamber (12) for allowing the pumping of a fluid. A wall portion (13) of the valve chamber is flexible, and a movable valve portion (14) set in a rest position of the valve chamber is sealed against the passage of fluid. The flow of fluid through the valve chamber is released corresponding to an opening position of the valve portion. The flow of fluid through the valve chamber is allowed by the deformation of the wall portion corresponding to an actuating position of the valve portion. An independent claim is included for pump base module.