waecE-LEARNING
Biology Paper 3,Nov/Dec 2011  
Questions:   1 2 4   Main
General Comments
Weakness/Remedies
Strength

















































Question 2


 

 


(   (a)    (i)    Identify the structure in the diagram
                   ------------------------------------------------------------------------------------------------------------------
                                                                                                                                                  [ 1 mark ]

 

          (ii)    Name the parts labeled I to X
                   I.  …………………………………………………………    VI. ……………………………………………………………..
                 II.  ………………………………………………………….    VII. …………………………………………………………….
                III.  …………………………………………………………     VIII. ……………………………………………………………
                 IV. ………………………………………………………..       IX. ……………………………………………………………
                  V.  ……………………………………………………….        X. …………………………………………………………….
                                                                                                                                                [ 5 marks ]
(iii)          State the function of the parts labeled II, III, V, VII and IX
                II.    ……………………………………………………..        VII. …………………………………………………………..
               III.    …………………………………………………….          IX. ……………………………………………………………
                V.    …………………………………………………….                                                         [ 5 marks ]
     (b)      What happens to the part labeled VIII in:
                 (i)    Bright light:……………………………………………………………………………………………………………..
                          ………………………………………………………………………………………………………………………………
                (ii)     Dim light:……………………………………………………………………………………………………………….
                          ………………………………………………………………………………………………………………………………
  (c)         (i)      List four defects associated with the structure in the diagram.
                         ………………………………………………………………………………………………………………………………..
                         ……………………………………………………………………………………………………………………………….
                        ………………………………………………………………………………………………………………………………..
                        ………………………………………………………………………………………………………………………………..
                                                                                                                                              [ 4 marks ]

 

              (ii)     State ways in which each of the defects in 2(c)(i) above can be corrected
                        ……………………………………………………………………………………………………………………………...
                         ……………………………………………………………………………………………………………………………..
                         …………………………………………………………………………………………………………………………….
                         ……………………………………………………………………………………………………………………………
                                                                                                                                     [ 4 marks]
             (d)       Outline four ways by which the structure in the diagram can be taken care of.
                         ……………………………………………………………………………………………………………………………..
                         …………………………………………………………………………………………………………………………….
                         …………………………………………………………………………………………………………………………….
                         …………………………………………………………………………………………………………………………….

                                                                                                                                    

                                                             [ 4 marks ]

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COMMENT

           This was the most popular question in this paper and the performance of the candidates was good.   Most candidates could correctly identify the structure as the eye and correctly name the labeled parts.  A few candidates however lost marks due to spelling errors.  Most candidates could not correctly spell “conjunctiva “ right.
           Again most candidates could correctly state the functions of the labeled parts however in stating the functions of the optic nerve some candidates stated that it carried images rather than impulses to the brain and so lost the score.
          Most candidates were stating the reaction of the pupil rather than the iris to light changes and many candidates made mistakes in outlining correction of eye defects.

      Effect of light changes on the iris .
           Dilates/elongates in bright light
           Contracts/shortens in  dim light.
            Defect                                                      (ii)      Correction
                  Short sightedness/Myopia                               Concave/diverging lens
                  Long sightedness/Hypermetropia                  Convex/converging lens
                  Astigmatism                                                        Cylindrical lens
                  Presbyobia                                                           Bifocal lenses
                  Cataract                                                                Surgery             
            Pterigium                                                             Medical

            Most candidates could however state how the eyes should be cared for and scored
            high marks.

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