You learned about DNA and proteins in your high school biology class, but you may not remember much about the cell’s membrane which is based on a dynamic, fluctuating sandwich structure. This cellular envelope controls what chemicals enter and exit the cell, partly due to molecular machines such as channels and pumps in the membrane, and partly due to the sandwich structure itself. This sandwich structure is a barrier to certain types of chemicals. But the membrane permeability and the operation of the molecular machines depend on the details of the sandwich structure. And as recent research has been finding, contra evolutionary expectations, organisms actively maintain and fine-tune the sandwich structure in response to environmental challenges. Read more