3B

• Plasma Membrane


  The phospholipid bilayer and embedded proteins which separate the intracellular environment from the extracellular environment. Also known as cell membrane
• Selective Permeability


  A property of cell membranes that ensures only specific substances pass across them. Also known as semipermeable
• 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 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
• Nonpolar


  Describes a molecule without a clearly positive or negative end. These tend to be hydrophobic
• Hydrophobic


  Having a tendency to repel and be insoluble in water
• Hydrophilic


  Having a tendency to be attracted to and dissolve in water
• Polar


  Describes a molecule with both a positive and negative end. These tend to be hydrophilic
• 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 phospholipid bilayer that selectively enable transport of large or polar molecules
• Carrier Protein

  A membrane protein that undergoes conformational changes 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 semi-permeable membrane, describes as hypertonic, hypotonic or isotonic
• Hypertonic


  Describes a solution with a higher solute concentration when compared to another solution
• Isotonic


  Describes a solution with the same solute concentration as another solution
• Hypotonic


  Describes a solution with a lower solute concentration when compared to another solution
• Turgid


  Describes plant cells that are swollen and firm from water uptake
• Plasmolyzed


  Describes plant cells with weak and sagging plasma membranes from water loss
• Lyse


  To cause a cell plasma membrane to burst or break