The plasma membrane of e. coli is approximately 75% protein and 25% phospholipid by weight. it is known that the average membrane protein molecular weight is 50,000 da and an average membrane phospholipid molecular weight is 750 da. calculate the number of membrane phospholipid molecules present per molecule of membrane protein. number phospholipid molecules per protein molecule select the additional information that one would need to calculate the fraction of membrane surface covered by phospholipids. the surface area of the e. coli cell the average cross-sectional areas of a 50,000 da protein and a 750 da phospholipid in a bilayer the average densities of a 50,000 da protein and a 750 da phospholipid the number of moles of protein and phospholipid 。in the membrane