Biology Chapters 2 and 3: Cell Structure and Membrane Dynamics

Vocabulary flashcards covering cell structure, membrane components, eukaryotic vs. prokaryotic features, and lipid dynamic behavior from Bio Chapter 2 and Chapter 3 lecture notes.

Cholesterol

A major amphipathic component of animal cell membranes (making up $30\%$ by mass of membrane lipids) that decreases membrane fluidity at high temperatures for stability and increases fluidity at low temperatures by preventing tight phospholipid packing.

Lipid Rafts

Regions within the lipid bilayer that contain discrete components rather than maintaining a uniform composition.

Lipid Flip

The movement of a hydrophilic head through the hydrophobic region of the lipid bilayer, altering the membrane's composition.

Red Blood Cell Membrane Proteins

Proteins that account for $50\%$ of the membrane mass of a red blood cell, functioning as transporters, receptors, enzymes, or anchors.

Integral Membrane Proteins

Proteins that are permanently associated with cell membranes.

Peripheral Membrane Proteins

Proteins that are temporarily associated with the lipid bilayer or internal membrane proteins, interacting with polar heads or integral membrane proteins through weak noncovalent bonds.

Transmembrane Proteins

The most common type of integral membrane proteins that span across the entire lipid bilayer.

Cell Theory

The fundamental principle that all organisms, from single-celled algae to complex multicellular organisms like humans, are made up of cells, which are 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, typically measure $1\text{--}2\,\mu\text{m}$ in diameter, have a high surface area to volume ratio, and possess a cell wall surrounding their membrane.

Eukaryotes

Organisms including animals, plants, fungi, and protists whose cells contain a nucleus and an extensive array of membrane-bound organelles.

Nucleoid

The discrete location in a prokaryotic cell where its genetic material, organized in one circular chromosome with many loops, is contained.

Organelles

Membrane-bound compartments in eukaryotic cells that divide cell contents into smaller spaces specialized for specific functions.

Eukaryotic Transcription and Translation

The process where transcription takes place inside the nucleus after mRNA is transcribed, followed by translation in the cytoplasm.

Phospholipids

The major lipids found in cell membranes, consisting of a glycerol backbone attached to a hydrophilic phosphate head and $2$ hydrophobic fatty acid tails.

Amphipathic

Refers to molecules that contain both hydrophilic (water-loving) and hydrophobic (water-fearing) regions.

Micelles

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

Liposomes

Spherical bilayer structures that form spontaneously when phospholipids are added to a test tube of water, capable of forming, breaking, re-forming, growing, and capturing nucleic acids and other macromolecules.