Plasma Membrane Structure and Functions

A set of vocabulary flashcards summarizing key concepts related to the plasma membrane, its structure, and functions.

Plasma Membrane

A thin, fragile structure that separates the cell from the external environment; 5–10 nm wide.

Lipid Bilayer

The fundamental structure of all membranes, consisting of two layers of phospholipids.

Compartmentalization

The division of cellular processes by enclosing different compartments within membranes.

Signal Transduction

The process by which a cell responds to external stimuli through membrane receptors.

Selective Permeability

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

Phosphoglycerides

Membrane lipids with a glycerol backbone and two fatty acid chains that form the bilayer.

Glycolipids

Lipids with carbohydrate attachments that are involved in cell recognition and signaling.

Integral Proteins

Proteins that span the entire membrane and have domains on both the extracellular and cytoplasmic sides.

Peripheral Proteins

Proteins that are associated with the membrane surface but do not penetrate the lipid bilayer.

Transport Proteins

Proteins that facilitate the movement of substances across the plasma membrane.

Oligosaccharides

Short sugar chains attached to proteins and lipids that contribute to cell recognition.

Cholesterol

A type of steroid that modulates membrane fluidity and stability.

Fluid Mosaic Model

A model that describes the structure of membranes as a mosaic of diverse proteins embedded in a flexible lipid bilayer.

Aquaporins

Channel proteins that facilitate the rapid transport of water across cell membranes.

Endocytosis

The process by which cells engulf substances from their external environment.

Exocytosis

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

Active Transport

The movement of substances against their concentration gradient, requiring energy.

Passive Transport

The movement of substances across the membrane without the use of energy.

Diffusion

The passive movement of molecules from an area of higher concentration to an area of lower concentration.

Facilitated Diffusion

The process by which specific molecules move across the membrane through protein channels.

Sodium-Potassium Pump

A primary active transport mechanism that moves Na+ out of and K+ into the cell.