Cell membranes

Definition

Cell membranes are biological structures that separate the interior of cells from the external environment. They function similarly to capacitors by maintaining potential differences across their bilayer, essential for cellular processes.

5 Must Know Facts For Your Next Test

1. Cell membranes can be modeled as parallel plate capacitors, with the lipid bilayer acting as an insulator.
2. The membrane potential is a result of ionic distributions across the cell membrane, similar to charge separation in a capacitor.
3. Capacitance per unit area of a typical cell membrane is around 1 $\mu$F/cm².
4. The dielectric constant of the lipid bilayer affects the capacitance value of the cell membrane.
5. Changes in membrane potential can influence ion channel activity, akin to how voltage changes affect capacitor behavior.

Review Questions

• How does the structure of a cell membrane resemble that of a parallel plate capacitor?
• What role does the dielectric constant play in determining the capacitance of a cell membrane?
• Explain how changes in membrane potential relate to capacitor voltage changes.

Related terms

Dielectric Constant: A measure of a material's ability to store electrical energy in an electric field; it affects capacitance.

Membrane Potential: The voltage difference across a cell's plasma membrane due to differential distribution of ions.

Ion Channels: Protein structures that allow specific ions to pass through the cell membrane and contribute to changes in membrane potential.