My husband and I *love* to walk ...for hours and hours, and if we decide to go ahead with this potential trip - I'm going to need good shoes. These days, I have some reasonably good shoes for the most part - but they are 2-3 hour walking shoes, not necessarily good for 6+ hours of tromping around.
In cell biology, selective permeability is the property of a living cell membrane that allows the cell to control which molecules can pass through the membrane, moving into or out of the cell.
Characteristic of a membrane which allows it to be permeable to some substances, and impermeable to others. See also: permeability. SELECTIVE PERMEABILITY: Membranes exhibiting selective permeability are employed in a variety of structures within the body..