Which of the Following Most Accurately Describes Selective Permeability

Question

Which of the following most accurately describes selective permeability?
A)An input of energy is required for transport.
B)Lipid-soluble molecules pass through a membrane.
C)There must be a concentration gradient for molecules to pass through a membrane.
D)Only certain molecules can cross a cell membrane.
E)Water-soluble molecules pass through a membrane.

Accepted Answer

Selective permeability refers to the ability of a membrane to selectively allow certain substances to pass through while restricting the passage of others. This means that only certain molecules, such as small nonpolar molecules or molecules that can pass through specific ion channels or transporters, can cross a cell membrane. Therefore, option D, "Only certain molecules can cross a cell membrane," is the most accurate choice. The other options are not necessarily true for all instances of selective permeability, as not all forms of transport require input of energy, and both lipid-soluble and water-soluble molecules can cross membranes depending on their size, charge, and other characteristics.