Plasma Membrane Structure & Function

These flashcards cover key vocabulary terms related to the structure and function of the plasma membrane, essential for understanding cell biology.

Plasma Membrane

The thin, flexible outer boundary of a cell, primarily composed of a phospholipid bilayer.

Phospholipid Bilayer

A double layer of phospholipids that forms the basic structure of the plasma membrane.

Selectively Permeable

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

Glycocalyx

A carbohydrate-rich outer layer made of glycoproteins and glycolipids that aids in cell adhesion and recognition.

Integral Proteins

Proteins that are permanently embedded in the plasma membrane.

Peripheral Proteins

Proteins that are temporarily attached to the surface of the membrane.

Fluid Mosaic Model

The model describing the plasma membrane as a mosaic of components that move fluidly.

Cholesterol

A lipid that helps maintain the structural integrity and fluidity of the plasma membrane.

Cytoskeleton

A network of fibers that maintains cell shape and aids in movement.

Active Transport

The movement of substances against their concentration gradient requiring energy.

Facilitated Diffusion

The passive transport of molecules across the membrane via protein channels.

Uniport

Transport of a single type of molecule across a membrane.

Cotransport

Transport of two different molecules simultaneously across a membrane.

Symport

Cotransport of two different molecules in the same direction across a membrane.

Antiport

Cotransport of two different molecules in opposite directions across a membrane.

Endocytosis

The process of engulfing substances into the cell via the membrane.

Exocytosis

The process of exporting substances out of the cell.

Transmembrane Proteins

Integral proteins that span the entire membrane and can form channels.

Ion Channels

Protein channels that allow specific ions to pass through the membrane.

Aquaporins

Specialized protein channels that facilitate water transport across the membrane.

Caveolae

Small, flask-shaped invaginations in the membrane involved in signal transduction.

Lipid Rafts

Microdomains in the membrane rich in cholesterol and glycosphingolipids.

G Protein-Coupled Receptors (GPCRs)

A large family of receptors that mediate cellular responses to ligands.

Signal Transduction

The process by which a cell converts an external signal into a functional response.

Glycolipids

Lipids with carbohydrate groups attached, found on the extracellular surface.

Na+/K+ Pump

An active transport mechanism that moves sodium out and potassium into the cell.

Cell Junctions

Specialized structures that mediate cell-to-cell adhesion and communication.

Channel-Linked Receptors

Receptors that open or close in response to the binding of a signaling molecule.

Catalytic Receptors

Receptors that have an enzymatic function and can initiate a biological response.

Receptor Tyrosine Kinases (RTK)

A class of catalytic receptors involved in cell signaling and growth.

Antigen Presentation

The display of foreign molecules on cell surfaces for immune recognition.

Hydrophilic

Substances that are attracted to water and can interact with it.

Hydrophobic

Substances that repel water and do not mix with it.

Amphipathic

Molecules that have both hydrophilic and hydrophobic parts, like phospholipids.

Clinical Correlation

The relevance of a biological mechanism to specific diseases or conditions.