6.5 Biological Membranes and Their Functions

These flashcards cover key vocabulary and concepts related to biological membranes, their structures, and functions.

Amphipathic

Molecules that have both hydrophilic (water-attracting) and hydrophobic (water-repelling) parts.

Phospholipid Bilayer

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

Selective Permeability

The property of biological membranes that allows them to regulate the passage of substances in and out of the cell.

Endomembrane System

A collection of membranes inside a eukaryotic cell that includes the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, and transport vesicles.

Flippases

ATP-dependent proteins that move phospholipids from the outer layer to the inner layer of the membrane.

Fluidity Buffer

A role of cholesterol in membranes to regulate fluidity by preventing tight packing at low temperatures and restricting movement at high temperatures.

Liposomes

Vesicles formed from lipid bilayers that can encapsulate aqueous solutions and deliver drugs to cells.

Transverse Movement

The movement of phospholipids from one side of the bilayer to the other, facilitated by specific membrane proteins.

Saturated Fatty Acids

Fatty acids with no double bonds, which pack tightly together, resulting in a more rigid membrane.

Unsaturated Fatty Acids

Fatty acids that contain one or more double bonds, introducing kinks that prevent tight packing and increase membrane fluidity.