To study surface changes in transformed cells using radioactive cell surfaces labelled metabolically (carbohydrate precursors) or chemically (reaction with pyridoxal phosphate and NaB3H4); to develop methods to isolate cell surface membranes; to compare membranes isolated from cloned transformed mouse embryo cells with those from cloned untransformed sister cell lines; to test for membrane differences which may depend upon the growth state of the cell, time after plating, or cell density.