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Biology Paper 2, Nov/Dec 2009  
Questions:   1 2 3 4 5 6 7 8   Main
General Comments

Question 3

  1.    (i)    Name the two stages of photosynthesis.      (2 marks)

  (ii)    Write chemical equations to represent each stage named in 3(a)(i) above. (6 marks)

  1.     In a tabular form state:
  2. three vitamins;
  3. one function;
  4. one deficiency symptom of each vitamin named.                                        (9 marks)


  1.     (i)    What is roughage?   (2 marks)

               (ii)    State one function of roughage.     (1 mark)



This was the most popular question in this section and candidates who attempted it did quite well.  Most candidates correctly named the two stages of photosynthesis but a good number
Of candidates however could not write chemical equations to represent each stage.  Some candidates who could correctly state the reactants and products could not list the correct conditions for the reactions. 
Expected answers are:
Light Stage
4 H2O                        Light/Energy   4H⁺  + 4(OH)
Dark stage                                    
4H + CO2                    Enzyme                                CH2O  +  H2O
                              Reduction process.
Most candidates performed well in stating the vitamins, their functions and deficiency symptoms and scored high marks.  A good number of candidates however did not separate Vit B into B1,2,3,or 12, they just stated vitamin B and so they lost some marks.    Most candidates who attempted the question could define roughage but nearly all of them could not state the functions of roughage.
 Expected answers include:
Functions of Roughage
For easy digestion of food; stimulates bowel movement/prevention of constipation; prevention of colon cancer.

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