Plasma Membrane Structure and Function

A set of vocabulary flashcards covering the structure, components, and major functions of the plasma membrane based on the lecture material.

Plasma Membrane

The flexible outer limiting membrane of a cell that separates the intracellular fluid within the cell from the extracellular fluid outside.

Intracellular Fluid

The fluid compartment located inside or within cells.

Extracellular Fluid

The fluid compartment located outside of cells.

Fluid Mosaic Model

A depiction of membrane structure as a double layer of lipid molecules with floating protein molecules dispersed throughout in a constantly changing pattern.

Phospholipid

The primary lipid constituent forming the basic fabric of the plasma membrane, composed of a polar hydrophilic head and two nonpolar hydrophobic tails.

Polar Hydrophilic Head

The region of a phospholipid containing a phosphate group that is attracted to water and lies on both the inner and outer surfaces of the membrane.

Nonpolar Hydrophobic Tail

The fatty acid region of a phospholipid that avoids water and lines up in the center of the lipid bilayer.

Cholesterol

A lipid with a typical 4-ring steroid structure that stiffens the membrane, decreases water solubility of the membrane, and can flip easily between lipid layers.

Integral Proteins

Membrane proteins that are directly embedded in the lipid bilayer.

Peripheral Proteins

Membrane proteins that are anchored to the membrane surface or attached to other proteins.

Glycocalyx

The cell-surface sugar coating formed by carbohydrates on the outside of the cell, acting as identity molecules for cell recognition.

Glycoproteins

Membrane proteins that have attached carbohydrate chains consisting of short chains of linked monosaccharides.

Glycolipids

Membrane lipids that have attached carbohydrate sugar chains on the outer membrane surface.

Selective Permeability

A plasma membrane function that determines which specific substances can enter or exit the cell.

Cytoplasm

The watery environment inside the cell enclosed by the plasma membrane.

Focus Figure 3.1: Building a Membrane

An illustrative guide detailing how phospholipids, cholesterol, integral/peripheral proteins, and carbohydrates assemble into the plasma membrane.

Functions of the Plasma Membrane

The primary roles of the membrane, including serving as a physical barrier, maintaining selective permeability, facilitating communication, and enabling cell recognition.