Lipids and Biological Membranes (5D) Practice Test

A group examined leaflet asymmetry by selectively adding a charged amphipathic lipid to the outer leaflet of living cells without immediate flip-flop to the inner leaflet. Within minutes, cells showed increased membrane curvature and budding in regions enriched with the added lipid. Which physical explanation is most consistent with how lipid geometry can influence membrane shape?

A group compared two synthetic vesicle membranes at 25°C: Membrane 1 contained phosphatidylcholine with mostly saturated 16:0 acyl chains; Membrane 2 contained phosphatidylcholine with mostly monounsaturated 18:1 acyl chains. Both had identical headgroups and no cholesterol. Which change is most expected when moving from Membrane 1 to Membrane 2 under these conditions?