Unit membranes

Definition

Unit membranes are the basic structural component of cellular membranes, consisting of a bilayer of phospholipids with embedded proteins. They form a barrier that separates and protects the interior of the cell from the external environment.

5 Must Know Facts For Your Next Test

1. Unit membranes exhibit a fluid mosaic model, where lipids and proteins can move laterally within the layer.
2. Phospholipids in unit membranes have hydrophilic heads and hydrophobic tails, creating a bilayer structure.
3. Cholesterol molecules within unit membranes help to modulate fluidity and stability.
4. Unit membranes are selectively permeable, allowing certain molecules to pass through while blocking others.
5. Integral proteins in unit membranes function as channels, carriers, or receptors for various substances.

Review Questions

• What is the primary structural component of unit membranes?
• Describe how cholesterol affects the properties of unit membranes.
• How do integral proteins contribute to the function of unit membranes?

Related terms

Phospholipid Bilayer: A double layer of phospholipids that forms the fundamental structure of all cell membranes.

Fluid Mosaic Model: A model describing the dynamic nature and composition of cell membranes, with lipids and proteins moving freely.

Selective Permeability: The ability of a membrane to allow certain molecules to pass through while blocking others.