Glycogen, cellulose, polypeptides and phospholipids all have large molecules.  
(a)   Which of these molecules is  
  (i) not found in a plant cell;  
    Glycogen (1)
  (ii) used primarily as a structural molecule?  
    Cellulose (1)
(b)   Give one element found in polypeptides that is not present in those of glycogen, cellulose or phospholipids.  
    Nitrogen (1)
The diagram represents a phospholipid molecule  
     
(c)   Name the following parts of the molecule  
  (i) A  
    Phosphate/Phosphate group (1)
  (ii) B  
    Glycerol (1)
  (iii) C  
    Fatty Acid (1)
(d)   Phospholipids are found in cell membranes. Proteins are also found in cell membranes, give two functions of proteins in cell membranes  
   
  • Carrier Molecules/Transport/Active Transport/Facilitated Diffusion;
  • Receptor molecules/Hormone receptors;
  • Membrane bound enzymes
(any 2)

 

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