Membrane Structure and Function

Vocabulary flashcards based on key concepts from the lecture notes on membrane structure and function.

Plasma Membrane

A biological membrane that separates and protects the interior of a cell from the external environment, regulating what enters and leaves the cell.

Lipid Bilayer

A double layer of lipids that forms the foundation of cell membranes, with hydrophilic heads facing outward and hydrophobic tails facing inward.

Selective Permeability

A property of the plasma membrane that allows certain molecules to pass through while blocking others.

Facilitated Diffusion

The process by which molecules pass through the plasma membrane with the help of transport proteins, without the use of energy.

Active Transport

The movement of molecules against their concentration gradient, requiring energy, typically in the form of ATP.

Osmosis

The diffusion of water across a selectively permeable membrane from a region of lower solute concentration to a region of higher solute concentration.

Aquaporins

Channel proteins in the plasma membrane that facilitate the rapid transport of water.

Tonicity

The ability of a surrounding solution to cause a cell to gain or lose water, which can be isotonic, hypertonic, or hypotonic.

Endocytosis

The process by which cells take in large molecules by engulfing them within vesicles formed from the plasma membrane.

Exocytosis

The process by which cells expel materials in vesicles that fuse with the plasma membrane.

Cotransport

A mechanism where active transport of one substance indirectly drives the transport of another substance.

Glycoproteins

Proteins that have carbohydrate chains attached to them and are important for cell-cell recognition and signaling.

Cholesterol

A type of lipid that stabilizes cell membranes at varying temperatures, affecting membrane fluidity.

Membrane Fluidity

The ability of the phospholipid bilayer to remain flexible, which is crucial for proper cell function.

Transport Proteins

Proteins that assist in moving substances across the plasma membrane, either passively or actively.