2.1.2 Cell Membranes

• Organelle

  Sub-cellular bodies found in the cytoplasm of cells
• Eukaryotes

  Group of organisms with cells that have the genetic material contained in a membrane-bound nucleus and also contain a number of membrane-bound organelles such as mitochondria and chloroplasts
• Prokaryotes

  Group of organisms including bacteria and blue-green algae (cyanobacteria) that have few organelles and do not have the genetic material contained in a membrane-bound nucleus
• Cell Surface Membrane

  membrane that forms the outer boundary of the cytoplasm of a cell and controls the movement of substances into and out of the cell
• Vesicle

  Membrane bound sac that hold chemical secretions made by the cell
• Polar Lipids

  Lipids with one end attached to a polar group, e.g a phosphate group that makes one end of the molecule hydrophilic and one end hydrophobic
• Gate channels

  Protein channels through the lipid bilayer of a membrane that are opened or closed, depending on conditions in the cell
• Fluid Mosaic Model

  Current model of the structure of the cell membrane including floating proteins forming pores, channels and carrier systems in a lipid bilayer