Chapter Three

Created by

Georgia Brooks

Cards (59)

Plasma membrane 
The phospholipid bilayer and embedded proteins which separate the intracellular environment from the extracellular environment. Also known as cell membrane
Intracellular 
Inside a cell
Extracellular 
Outside a cell
Selective permeability 
A property of cell membranes that ensures only specific substances pass across them. Also known as semipermeable
Phospholipid 
The main molecule of which membranes are composed. They have a phosphate head and two fatty acid tails
Phospholipid bilayer 
A double layer of amphiphilic molecules that forms the primary component of cell membranes
Phosphate head 
The hydrophilic subunit of a phospholipid
Fatty acid tail 
The hydrophobic lipid subunit of a phospholipid
Hydrophilic 
Having a tendency to be attracted to and dissolve in water
Polar 
Describes a molecule with both a positive end and negative end. These tend to be hydrophilic
Hydrophobic 
Having a tendency to repel and be insoluble in water
Nonpolar 
Describes a molecule without a clearly positive or negative end. These tend to be hydrophobic
Amphipathic 
Describes molecules with both hydrophilic and hydrophobic components. Also known as amphiphilic
Protein 
A class of biomacromolecule made of amino acid monomers folded into a 3D shape, consisting of carbon, hydrogen, oxygen, nitrogen, and sometimes sulphur
Carbohydrate 
A class of biomacromolecule made from monosaccharide monomers consisting of carbon, hydrogen, and oxygen. Also known as saccharides or sugars
Cholesterol 
A steroid-alcohol that regulates fluidity in plasma membranes
Integral protein 
A protein that is permanently secured to the plasma membrane
Transmembrane protein 
An integral protein that spans the entire plasma membrane
Peripheral protein 
A protein that is temporarily attached to the plasma membrane
Cytoskeleton 
The microscopic web of protein filaments in the cytoplasm. It provides structure and support, and transports products around the cell
Glycolipid 
A phospholipid bound to a carbohydrate
Glycoprotein 
A protein bound to a carbohydrate
Fluid mosaic model 
The theory of how the plasma membrane is structured
Saturated 
A fatty acid chain with only single bonds between carbon atoms
Unsaturated 
A fatty acid chain with at least one double or triple bond between carbon atoms
Cytosol 
The aqueous fluid that surrounds the organelles inside a cell
Passive transport 
The movement of molecules through a semipermeable membrane and down the concentration gradient, without an input of energy
Active transport 
Movement of molecules across a semipermeable membrane that requires energy
Diffusion 
The passive movement of molecules from areas of high concentration to areas of low concentration (down the concentration gradient)
Concentration gradient 
The difference in solute concentration between two adjacent areas
Kinetic energy 
The energy a particle or body possesses due to motion
Solute 
A substance dissolved in the solvent
Solvent 
A liquid in which a solute is dissolved, forming a solution
Facilitated diffusion 
A type of passive transport where molecules move through a phospholipid bilayer with the aid of a membrane protein
Protein channel 
A transmembrane protein pore in a phospholipid bilayer that selectively enables transport of large or polar molecules
Carrier protein 
A membrane protein that undergoes conformational change to transport molecules across a membrane
Conformational change 
A change in the three-dimensional shape of macromolecules such as proteins
Osmosis 
The passive transport of a solvent (typically water) through a semipermeable membrane from a region of low solute (high solvent) to a region of high solute (low solvent)
Tonicity 
A measure of the relative concentration of solutes on either side of a semipermeable membrane, described as hypertonic, hypotonic, or isotonic
Hypertonic 
Describes a solution with a higher solute concentration when compared to another solution