Prokaryotic cells are surrounded by a plasma membrane, but they have no internal membrane-bound organelles within their cytoplasm. The absence of a nucleus and other membrane-bound organelles ...

Thus, the hydrophilic heads of the glycerophospholipids in a cell's plasma membrane face both the water-based cytoplasm and the exterior of the cell. Altogether, lipids account for about half the ...

The plasma membrane has distinct regions called ... This helix is embedded in the membrane's cytoplasmic leaflet and stabilized by phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), a negatively ...