A module, a base module and a system which comprises a module and a base module includes a pump channel and a valve unit which is connected with the pump channel wherein a fluid can be pumped through the pump channel and the valve unit, wherein a first wall section of the valve unit is flexible. The pump module has a movable valve body arranged in the valve unit, wherein the valve body can occupy an idle position in which the valve body closes the valve unit to prevent fluid from passing through. The valve body can occupy an operating position in which the valve body allows the fluid to flow through the valve unit and in which the valve body can be put in operating position through a deformation of the first wall section of the valve bodies so that the fluid can flow through the valve unit.