cell transport

• Active transport 


  Movement of a substance from a region where it is in a low concentration to a region where it is in a high

  concentration. The process requires the expenditure of metabolic energy in the form of ATP.
• Bilayer  


  A membrane consisting of two layers of phospholipids.
• Carrier Protein 


  A protein completely spanning the phospholipid bilayer which bind to ions or molecules then change shape

  in order to move these molecules across the membrane.
• Cell membrane 


  A selectively permeable membrane surrounding the cell and controlling the entry and exit of materials
• Cholesterol


   

  Lipid that is an important component of cell-surface membranes because it adds strength. Excess in the

  blood can lead to atheroma.
• Fluid mosaic model 


  The arrangement of the various molecules of the cell-surface membrane. Fluid because the individual

  phospholipid molecules can move relative to one another and mosaic because the proteins vary in shape,

  size and pattern.
• Glycolipid 


  A carbohydrate covalently bonded with a lipid. They act as recognition sites, help maintain stability of the

  membrane and help cells attach to one another.
• Glycoprotein 


  Carbohydrate chains attached to a protein (often extrinsic) which are part of the cell surface membrane.

  They act as recognition sites, help cells to attach to one another and allows cells to recognise one another.
• Partially permeable


  Also called semi-permeable. A partially permeable membrane allows water and other small molecules to

  pass through, but not larger molecules such as starch.
• Permeability 


  How permeable a substance is depends on the size, polarity and charge of the molecule. If it is small, non-

  polar and fat soluble it is very permeable and can pass through the cell membrane.
• Phospholipid 


  Triglyceride in which one of the three fatty acid molecules is replaced by a phosphate molecule.

  Phospholipids are important in the structure an functioning of plasma membranes.
• Plasma Membrane 


  Membranes consisting of a phospholipid bilayer found around and within all cells. The cell-surface

  membrane is the plasma membrane that surrounds cells.
• Protein Channel 

  A protein completely spanning the phospholipid bilayer which form water-filled tubes to allow water-soluble

  ions to diffuse across the membrane.
• Bilayer 


  A membrane consisting of two layers of phospholipids.  
• Carrier Protein 


  A protein completely spanning the phospholipid bilayer which bind to ions or molecules then change shape in order to move these molecules across the membrane. 
• Cell membrane


  A selectively permeable membrane surrounding the cell and controlling the entry and exit of materials
• Cholesterol


   

  Lipid that is an important component of cell-surface membranes because it adds strength. Excess in the blood can lead to atheroma. 
• Concentration


  The concentration of a solution tells us how much of a substance is dissolved in water. The higher the concentration, the more particles of the substance are present.
• Diffusion 

  The net movement of molecules (or ions) from a region of high concentration to a region of low concentration. It is passive.  
• Partially permeable


  Also called semi-permeable. A partially permeable membrane allows water and other small molecules to pass through, but not larger molecules such as starch.
• Permeability 


  How permeable a substance is depends on the size, polarity and charge of the molecule. If it is small, non-polar and fat soluble it is very permeable and can pass through the cell membrane. 
• Phospholipid 


  Triglyceride in which one of the three fatty acid molecules is replaced by a phosphate molecule. Phospholipids are important in the structure an functioning of plasma membranes. 
• Plasma Membrane 


  Membranes consisting of a phospholipid bilayer found around and within all cells. The cell-surface membrane is the plasma membrane that surrounds cells.  
• Protein Channel 

  A protein completely spanning the phospholipid bilayer which form water-filled tubes to allow water-soluble ions to diffuse across the membrane. 
• Solvent


  The liquid in which the solute dissolves to form a solution.
• Carrier Protein 


  A protein completely spanning the phospholipid bilayer which bind to ions or molecules then change shape in order to move these molecules across the membrane. 
• Cell membrane


  A selectively permeable membrane surrounding the cell and controlling the entry and exit of materials
• Channel Protein

  A protein completely spanning the phospholipid bilayer which form water-filled tubes to allow water-soluble ions to diffuse across the membrane. 
• Concentration


  The concentration of a solution tells us how much of a substance is dissolved in water. The higher the concentration, the more particles of the substance are present.
• Co-transport 


  The transport of one substance coupled with the transport of another substance across a plasma membrane in the same direction through the same protein carrier. 
• Diffusion 

  The net movement of molecules (or ions) from a region of high concentration to a region of low concentration. It is passive.  
• Facilitated diffusion 


  
  

  Diffusion involving the presence of protein carrier molecules to allow the passive movement of substances (normally large, polar or charged molecules) across plasma membrane. 
• Net

  Overall.
• Partially permeable


  Also called semi-permeable. A partially permeable membrane allows water and other small molecules to pass through, but not larger molecules such as starch.
• Passive transport


  Transport of molecules that occurs as a result of the random movement of particles, so that there is a net movement from a higher to a lower concentration. Passive transport does not require energy.
• Cell sap


  The liquid found in the vacuole of plant cells, consisting of water with dissolved sugars, salts and amino acids
• Cell wall


  Outer structure which provides support and prevents the cell from bursting from the uptake of water by osmosis. Plant, fungal and bacterial cell walls have different structures and chemical compositions.
• Cellulose


  A carbohydrate. It forms the cell wall in plant cells.
• Concentration


  The concentration of a solution tells us how much of a substance is dissolved in water. The higher the concentration, the more particles of the substance are present.
• Cytoplasm


  The living substance inside a cell (not including the nucleus).