Some amphiphatic compounds cause red blood cells to form small bubbles on their surface. This process is called crenation and these compounds are referred to as crenators. Other amphiphatic compounds cause the formation of invaginations and pits on the red cell surface. These compounds are called cup formers. Give an explanation for the following observations made at pH 7.4 :

1. compounds of the type Ar(CH2)3N+(CH3)3 are crenators of intact red blood cells, but cup formers with unsealed red blood cells ghosts ("ghosts" are red blood cells which have been lysed to release hemoglobin). Ar is an aromatic moiety.

2. compounds of the type Ar(CH2)3N (CH3)2 are cup formers with both intact red blood cells and unsealed red blood cell ghosts