Semipermeable

Definition

Semipermeable describes a membrane that allows certain molecules or ions to pass through it by diffusion and occasionally specialized processes. This selective permeability is crucial in biological and medical applications.

5 Must Know Facts For Your Next Test

1. Semipermeable membranes are essential for osmosis, enabling the movement of water across the membrane while restricting other substances.
2. In nerve conduction, semipermeable membranes help maintain ion gradients, which are critical for action potential propagation.
3. Dialysis machines use semipermeable membranes to filter waste products from the blood while retaining necessary molecules.
4. The lipid bilayer of cell membranes is naturally semipermeable due to its hydrophobic and hydrophilic regions.
5. Electrochemical gradients across semipermeable membranes drive ATP synthesis in mitochondria.

Review Questions

Related terms

Osmosis:

The process by which water molecules move across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Diffusion:

The net movement of particles from an area of higher concentration to an area of lower concentration until equilibrium is reached.

Action Potential:

$$A rapid change in electric potential that occurs when a nerve cell membrane is stimulated, allowing ions to flow across the semipermeable membrane.$$