What Does It Mean That Biological Membranes Are Selectively Permeable

It is the ability of something to be permeable.

Selectively permeable means a membrane allows the passage of some molecules or ions and inhibits the passage of others. All cells are enclosed with a cell membrane. The actual structure of the cell membrane allows free passage or restricts movement of substances across the membrane. Updated september 09 2019.

The capacity to filter molecular transport in this manner is called selective permeability. That is to allow substances to pass through indiscriminately. A selectively permeable cell membrane is one that allows certain molecules or ions to pass through it by means of active or passive transport. Selective permeability definition selective permeability is a property of cellular membranes that only allows certain molecules to enter or exit the cell.

The cell membrane is said to be selectively permeable because it lets certain substances pass through while restricting the passage of others.