Comprehensive Study Notes on Cell Biology, Membrane Structure, and Dynamics

Vocabulary flashcards covering cell membrane composition, lipid behavior, membrane proteins, and cellular structures from Biology Chapters 2 and 3.

Cholesterol

A major amphipathic component of animal cell membranes, accounting for $30\%$ by mass of membrane lipids, which decreases fluidity at high temperatures and increases fluidity at low temperatures.

Amphipathic

Describing molecules, such as phospholipids and cholesterol, that contain both hydrophilic and hydrophobic regions.

Lipid Rafts

Discrete regions within the lipid bilayer that contain specific individual components.

Lipid Flip

The movement of a hydrophilic head through the hydrophobic core of the membrane, altering its composition.

Integral Membrane Proteins

Proteins that are permanently associated with cell membranes.

Peripheral Membrane Proteins

Proteins temporarily associated with the lipid bilayer or integral membrane proteins through weak noncovalent interactions.

Transmembrane Proteins

The majority of integral membrane proteins that span across the entire lipid bilayer.

Cell Theory

The foundational concept stating that all organisms are made up of cells and that the cell is the fundamental unit of life.

Anton

The Dutch microbiologist who discovered unicellular organisms, including bacteria, protists, and algae.

Prokaryotes

Organisms such as bacteria and archaea that lack a nucleus and typically measure $1\text{--}2\,\mu\text{m}$ in diameter.

Eukaryotes

Organisms including animals, plants, fungi, and protists whose cells contain a nucleus and specialized internal compartments.

Nucleoid

The discrete region in a prokaryotic cell containing its genetic material organized into one circular chromosome with many loops.

Organelles

Specialized membrane-bound compartments in eukaryotic cells that divide cellular contents into distinct functional spaces.

Nucleus

An organelle in eukaryotic cells where transcription takes place prior to mRNA translation in the cytoplasm.

Phospholipids

The primary lipid component of cell membranes, composed of a glycerol backbone, a hydrophilic phosphate group head, and two hydrophobic fatty acid tails.

Micelles

Spherical structures formed by wedge-shaped lipids that have a bulky hydrophilic head and a single hydrophobic tail.

Liposomes

Spherical bilayer structures that form spontaneously when phospholipids are added to a test tube of water.