Lipid-bilayer

Definition

A lipid bilayer is a double-layered structure of phospholipids that forms the fundamental architecture of all cell membranes. It acts as a barrier to protect cellular contents and regulates the movement of substances in and out of the cell.

5 Must Know Facts For Your Next Test

1. The lipid bilayer is composed primarily of phospholipids with hydrophilic heads and hydrophobic tails.
2. It provides fluidity and flexibility to the cell membrane, allowing for membrane protein movement and cell signaling.
3. Cholesterol molecules within the bilayer contribute to membrane stability by modulating its fluidity.
4. Embedded proteins within the lipid bilayer perform various functions including transport, signal transduction, and structural support.
5. The asymmetrical distribution of lipids between the inner and outer leaflets is crucial for cellular processes like apoptosis and vesicle formation.

Review Questions

• What are the primary components of a lipid bilayer?
• How does cholesterol affect the properties of the lipid bilayer?
• Why is the asymmetry of lipid distribution important in cellular processes?

Related terms

Phospholipid: A type of lipid molecule that forms the basic structural component of all cell membranes.

Cholesterol:

A type of lipid molecule that modulates membrane fluidity and stability in eukaryotic cells.

Integral Protein: Proteins embedded within or spanning across the lipid bilayer, involved in various cellular functions.