'Shocking' Secret of Cell Wall Growth (video) Stanford School of Engineering Loading video... Caption Cells are porous. They shrink or swell in response to osmosis -- the migration of water across a membrane to equalize pressure inside and out. This video uses advanced microscopy to teach biologists something new. They had thought cell walls did not grow as fast under high external osmotic pressure. But this time-lapse movie shows E. coli cells suddenly growing engorged when put under low osmotic pressures, like raisins turning back into grapes, as water rushed back into the cells to reveal wall growth that had occurred, but remained hidden. Credit: Enrique Rojas Credit Enrique Rojas Usage Restrictions With attribution and in association with the story about this research 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.