1.1.4 - Plasma membrane

Phospholipid Bilayer

A double layer of phospholipids that makes up the plasma membrane, with hydrophilic heads facing outward and hydrophobic tails facing inward.

Fluid Mosaic Model

Describes the plasma membrane structure, where lipids and proteins move fluidly within the bilayer, resembling a mosaic.

Selective Permeability

The property of the plasma membrane that allows certain molecules to pass while restricting others.

Osmosis

The passive movement of water across a semipermeable membrane from an area of high water concentration to an area of low water concentration.

Glycolipid

A lipid molecule with carbohydrate chains attached that functions as receptors for messenger molecules and stabilizes the plasma membrane.

Glycoprotein

A protein molecule with carbohydrate chains attached that functions as receptors for messenger molecules and stabilizes the plasma membrane.

Active Transport

The movement of substances across the plasma membrane against the concentration gradient, requiring energy in the form of ATP.

Facilitated Diffusion

The passive movement of molecules across the plasma membrane with the help of membrane proteins.

Endocytosis

The active transport of macromolecules into the cell via vesicle formation.

Exocytosis

The active transport of macromolecules out of the cell by a vesicle fusing with the plasma membrane.

Equilibrium

The state when equal numbers of a specific molecule are present on either side of the plasma membrane.

Concentration Gradient

The unequal distribution of a substance across the plasma membrane, driving diffusion.

Passive Transport

The movement of substances across the plasma membrane without the input of energy.

Cholesterol

A steroid molecule embedded in the plasma membrane that regulates its fluidity.

Integral Protein

A protein that spans across the plasma membrane, involved in transporting molecules.

Peripheral Protein

A protein that is attached to one side of the plasma membrane, usually involved in signaling.