Cortical Polarity in a Yeast Cell (IMAGE) Max-Planck-Gesellschaft Caption A) Cortical polarity in a yeast cell: Fluorescent Cdc42 molecules form a cap in the membrane of a yeast cell (arrow). A fluid-filled vacuole inside the cell appears as a white circle. The white bar indicates two micrometres. B) Schematic model of cortical polarity and its molecular mechanisms: diffusion (double sided arrows), active transport (arrows towards the plasma membrane) and endocytosis (arrows away from the plasma membrane). Taken together they allow the accumulation of Cdc42 molecules (blue circles) and the creation of a cap. Credit Max Planck Institute of Biochemistry Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.