mass transport

• The rate of diffusion is directly proportional to the surface area, so increasing the surface area increases the rate.
• The active movement of substances from a low concentration to a higher concentration (up their concentration gradient) with the use of energy in the form of ATP.


  Active Transport
• The energy currency of cells which is composed of a

  molecule of adenosine bound to three consecutive phosphate groups.


  Adenosine triphosphate (ATP)
• The passive net movement of molecules from an area of high concentration to an area of low concentration.

  Diffusion
• The bulk uptake of substances into a cell by invagination of the membrane to form a vesicle trapping the substances inside the cell with the use of energy in the form of ATP.

  Endocytosis
• The bulk transport of substances out of a cell using a vesicle that fuses with the plasma membrane using energy in the form of ATP.

  Exocytosis
• The net movement of substances from a high concentration to a

  lower concentration (down their concentration gradient) through transport proteins without the use of energy.

  Facilitated diffusion
• A model that describes membrane structure as a sea of mobile

  phospholipids studded with various proteins.

  Fluid mosaic model
• A molecule which is attracted to water

  hydrophilic
• A molecule which repels water

  hydrophobic
• The diffusion of water molecules from an area of high water potential to an area of lower water potential through a partially permeable membrane

  Osmosis
• The ingestion of solid material (particularly pathogens and foreign material) by phagocytic cells

  Phagocytosis
• A type of lipid formed by the condensation of one molecule of glycerol, two molecules of fatty acid and a phosphate group.

  Phospholipid
• The force that the water within a plant cell exerts on the cell membrane which pushes it against the cell wall.

  Turgor pressure