Jackson has a pcd (primary cilia dyskinesia) where his cilia have defects that affect their motility. how is this related to jackson's respiratory symptoms?

The PCD is an abbreviation used for the primary cilia diskinesia disease. This condition result in the reduced motility of the cilia.  

In respiratory tract, the cilia help the mucus to flow above the respiratory tract. In case, the cilia is damaged, or it is not able to move, then the mucus cannot move out of the respiratory tract  and cause many respiratory abnormalities, such as congestion, infection, bronchitis, cough, short of breath, ear infections etc.  

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.