Cell Membrane Flashcards

Vocabulary flashcards based on the lecture notes about the cell membrane.

Cell Membrane

A biological membrane that separates the interior of cells from the outside environment.

Plasma Membrane

Another name for the cell membrane.

Extracellular Space

The environment outside of the cell.

Lipid Bilayer

The main component of the cell membrane, consisting of two layers of lipid molecules.

Cholesterol

A lipid that sits between phospholipids to maintain membrane fluidity.

Integral Proteins

Membrane proteins that go across the membrane, often serving as membrane transporters.

Peripheral Proteins

Membrane proteins that loosely attach to the outer side of the lipid bilayer.

Selectively Permeable

The property of the cell membrane that allows it to control the movement of substances in and out of cells.

Hydrophilic Heads

The phosphate group heads of phospholipids that orient themselves to face outwards in an aqueous solution.

Hydrophobic Tails

The fatty acid tails of phospholipids that are on the inside of the bilayer.

Cell Adhesion

The process by which cells attach to other cells or surfaces.

Ion Conductivity

The ability of the cell membrane to conduct ions.

Cell Signaling

The process by which cells communicate with each other.

Glycocalyx

The carbohydrate layer on the outer surface of the cell membrane.

Cytoskeleton

The intracellular network of protein fibers that attaches to the cell membrane.

Phospholipids

Lipid molecules made up of a phosphate group head and two fatty acid tails.

Glycolipids

Lipids with a carbohydrate attached.

Glycoproteins

Proteins with a carbohydrate attached.

Oligosaccharides

A small percentage of carbohydrates that may be attached to lipids or proteins in the cell membrane.

Amphiphilic

Having both hydrophobic and hydrophilic regions.

Transmembrane Proteins

Integral proteins that extend through the lipid bilayer.

Fluid Mosaic Model

A model of the cell membrane as a two-dimensional liquid where lipids and proteins diffuse more or less freely.

Membrane Asymmetry

The unequal distribution of molecules between the two monolayers of the cell membrane.

Monolayers

Each individual layer of the lipid bilayer.

Membrane Fluidity

The ability of the cell membrane to change shape and not be fixed in position.

Lipid Saturation

Saturation of fatty acid tails affecting membrane fluidity.

Enzymatic Proteins

Proteins in the plasma membrane that act as enzymes.

Receptor Molecules

Molecules in the plasma membrane that can bind to cell signaling molecules.

Sandwich Model

An outdated model of the cell membrane that proposed two layers of lipid molecules.

Unit Membrane Model

An outdated model suggesting a lipid bilayer sandwiched by proteins.

Cell-recognition processes

Function of Glycolipids protruding outwards.

Hydrophobic Regions

Region of proteins interacting with the hydrophobic tails of the lipid molecules.

Hydrophilic Regions

Region of proteins exposed to water on either side of the membrane.

Cell receptors

Proteins that are permanent parts of the membrane.

integral proteins

play a role in Cell receptors.

enzymes

Peripheral proteins act as _ shaping the cell

Prokaryotic Cells

Cells that contain a plasma membrane.

Eukaryotic Cells

Cells that contain a plasma membrane.

Lipids

40-45% of the plasma membrane.

Proteins

50-55% of the plasma membrane.

Carbohydrates

1-5% of the plasma membrane.

S.J.Singer

Person who studied phospholipid bilayers and found that they can form a flattened surface on water, with no requirement for a protein coat.

Integral Proteins

Proteins that are responsible for cell adhesion (attach a cell to another cell or surface).

Peripheral Proteins

Proteins that are temporarily associated with the membrane.

Membrane

Fairly rigid and can burst if penetrated

Fluid

Individual phospholipids and some proteins can move sideways in the layer so creates fluid structure

Mosaic

Range of different proteins resting on the surface or through phospholipid layer, therefore creating mosaic appearance

Carbohydrates

Mostly present in the outer monolayer of the plasma membrane, forming the so-called glycocalyx (contributing to the asymmetry)

Outer Monolayer

Carbohydrates are mostly present in the _ of the plasma membrane.

Fatty Acid Tails

Phospholipids may vary in the length and relative saturation of the .