Abstract: Compounds capable of functioning as membrane mobility agents in plant and animal cells are described. These compounds have a structure represented by the formula ##STR1## in which A represents a hydrophilic chain; Z represents either an ester linkage ##STR2## an amide linkage ##STR3## or an ether linkage (--O--); R.sub.1 represents either a straight-chain alkyl group or a straight-chain alkyl group interrupted by one or more cyclopropyl groups; R.sub.2 and R.sub.3 each represent either hydrogen, lower alkyl, or a halogen group; and x represents an integer from 2 to 10.The membrane mobility agents of the invention promote the lateral mobility through cell membranes of molecules ranging in size from phospholipids to surface antigens. They represent a new class of biologically active molecules which may be used to alter the mobility of membrane components in animal and plant cells to alter such cells in their response to external stimuli.