Topic outline

  • practical requqirements

    BIOLOGY PAPER 3( PRACTICAL) REQUIREMENTS

     

    Each candidate will require the following:

    Ø Twig of Hibiscus with a flower- Specimen A

    Ø Twig of grass – Specimen B

    Ø 1 ml Olive oil

    Ø K1 (Concentrated sodium hydrogen carbonate solution)

    Ø K2 (1% starch solution)

    Ø Irish potato

    Ø Four Test tubes

    Ø 2 droppers

    Ø Access to iodine solution

    Ø Four labels

    Ø Iodine solution

     

    NB:

    -         1% starch solution is prepared by mixing 1 gram of pure starch to 100cm3 of distilled water.

    -         For better results ensure your school buys Olive oil.

     


    • the practical questions

      BIOLOGY PAPER THREE SAMPLE QUESTIONS

      1. You are provided with specimen A and B

      a)   Name the sub-division to which the specimen belong                                 (1mk)

      …………………………………………………………………………………………………...

      b)   Name the class to which the specimens belong                                          (2mks)

      A…………………………………………..

      B…………………………………………..

      c)   State three observable differences between the leaves of specimen A and B            (3mks)

      Leaves A

      Leaves B

       

       

       

       

       

       

      d)  The diagram below show the cross-sections of stems obtained from specimens A and B

       

       

       

       

       

       

       

       

       

      (i)        Match the stem cross-sections with the specimens                            (2mks)

      ……………………………………………………………………………………………………………………………………………………………………………………………….

       

       

       

       

      (ii)       Outline three differences between the two stems                               (3mks)

      Specimen A1

      Specimen B1

       

       

       

       

       

       

       

      e)   Suggest the agent of pollination of the flowers of specimen A                      (1mk)

      ………………………………………………………………………………………………..

      Give reason for your answer                                                              (1mk)

      …………………………………………………………………………………………………

       

      1. You are provided with photographs of specimens labeled K (gills) and L (lungs). Examine them and answer the questions that follow.

       

       

       

       

       

       

       

       

      (a) Name the class of organisms from where the specimens were obtained                  (2mks)

      Specimen

      Class

      K

       

      L

       

       

      (b) Label all the parts of specimen K on the photograph                                          (3mks)

      I…………………………

      II………………………..

      III………………………

      (c) State the functions of each of the parts you have labeled in (b) above                    (3mks)

      ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

      (d) State three ways in which the part labeled L is adapted to its functions                       (6mks)

      ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

      (e) State the functional relationship between specimens K and L                              (1mk)

      ………………………………………………………………………………………………………………………………………………………………………………………………………………

      1. You are provided with:

      ·         1ml Olive oil

      ·         K1 (Concentrated sodium hydrogen carbonate solution)

      ·         K2

      ·         Irish potato

      ·         Test tube

      ·         Iodine solution

      Label two test tubes X and Y. Into each test tube; put 2cm3 of water and 8 drops of Olive oil. To the test tube labeled X, add 8 drops of Liquid K1.  Shake both test tubes and allow the contents to stand for 2 minutes

                        a)(i) Record your observation in:                                                               (2mks)

      Test tube X

      ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

      Test tube Y

      ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

      (ii) Name the process that has taken place in test tube X                                    (1mk)

                    …………………………………………………………………………………………………

                 (iii) Stage the significance of the process named in (a) (i) above in digestion                (1mk)

                    ………………………………………………………………………………………………….

                 (iv) Name the:

                             I.      Digestive juice in human beings that has the same effect on oil as liquid K1   (1mk)

      ………………………………………………………………………………………

                            II.      Region of alimentary canal where the juice is secreted                      (1mk)

      …………………………………………………………………………………………

               b)          Label two test tubes E and F. place 2cm3 of liquid K2 into each. Add a drop of iodine solution into each test tube

      (i)        Record your observations                                                          (1mk)

      ………………………………………………………………………………………….

      (ii)       Suggest the identity of liquid K2                                                     (1mks)

      …………………………………………………………………………………………

      (iii)      Cut out a cube whose sides are 1cm from the irish potato provided. Crush the cube to   obtain a paste and place the paste in the test tube labeled E. Leave the set up for at least 30minutes

                      Record your observations                                                              (2mks)

                      ……………………………………………………………………………………………….

                      ………………………………………………………………………………………………

                      ……………………………………………………………………………………………….

      (iv)      Account for the results in (b) (iii) above                                           (2mks)

      ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….

       

       

       

       

       

       


      • practical results and analysis

        BIOLOGY SAMPLE PAPER THREE – MARKING SCHEME

        1. You are provided with specimen A and B

        a)   Name the sub-division to which the specimens belong                                (1mk)

        Angiospermae/Angiospermaphyta

        b)   Name the class to which the specimens belong                                          (2mks)

        A- Dicotyledonae

        B - Monocotyledonae

        c)   State three observable differences between the leaves of specimen A and B            (3mks)

        Leaves A

        Leaves B

        Network veined

        Parallel veined

        Has a petiole

        Has a sheath

        Broad lamina/leaf blade

        Narrow lamina / leaf blade

        d)  The diagram below show the cross-sections of stems obtained from specimens A and B

         

         

         

         

         

         

         

         

         

        (i)        Match the stem cross-section with the specimen                               (2mks)

        A-A1

        B-B1

         

         

         

         

        (ii)       Outline three differences between the two stems                               (3mks)

        Specimen A1

        Specimen B1

        Vascular bundles arranged in a ring

        Vascular bundles scattered in the stem

        Has a distinct cortex and pith

        Pith and cortex absent

        Vascular cambium present

        Vascular cambium absent

         

        e)   Suggest the agent of pollination of the flowers of specimen A                      (1mk)

        Insect

        Give reason for your answer                                                              (1mk)

        Brightly coloured petals to attract insects

         

        1. You are provided with photographs of specimens labeled K (gills) and L (lungs). Examine them and answer the questions that follow.

         

         

         

         

         

         

         

         

        (a) Name the class of organisms from where the specimens were obtained                  (2mks)

        Specimen

        Class

        K

        Pisces

        L

        Mammalia

         

        (b) Label all the parts of specimen K on the photograph                                          (3mks)

        I.          Gill bar

        II.         Gill rakers

        III.        Gill filaments

        (c) State the functions of each of the parts you have labeled in (b) above                    (3mks)

        Gill bar      -      Supports the gill filament

        Gill filaments      -      Form the site of gaseous exchange

        Gill rankers -      Protect the delicate gill filaments from damage by solid particles

         

         

        (d) State three ways in which the part labeled L is adapted to its functions                       (6mks)

        -          Made of spongy elastic tissue that expands to accommodate a large volume of air

        -          Made up of numerous alveoli to provide a large surface area for gaseous exchange

        -          Supplied with numerous blood capillaries to maintain a high concentrated gradient for quick transportation of gases

        (e) State the functional relationship between specimens K and L                              (1mk)

        Both are gaseous exchange organs in the organisms where they are found

        1. You are provided with:

        ·         1ml Olive oil

        ·         K1 (Concentrated sodium hydrogen carbonate solution)

        ·         K2 (1% starch solution)

        ·         Irish potato

        ·         Test tube

        ·         Iodine solution

        Label two test tube s X and Y. Into each test tube; put 2cm3 of water and 8 drops of Olive oil. To the test tube labeled X, add 8 drops of Liquid K1.  Shake both test tubes and allow the contents to stand for 2 minutes

                          a)(i) Record your observation in:                                                               (2mks)

        Test tube X

        Liquid becomes cloudy/turbid, suspension formed/oil broken up into small droplets which are dispersed throughout the liquid. The oil becomes emulsified.

        Test tube Y

        Oil floats on the water/two separate /immiscible layers are formed

        (ii) Name the process that has taken place in test tube X                                    (1mk)

                Emulsification

                   (iii) Stage the significance of the process named in (a) (i) above in digestion                (1mk)

                Increases surface area for action of lipase enzyme

                   (iv) Name the:

                               I.      Digestive juice in human beings that has the same effect on oil as liquid K1   (1mk)

                              II.       

        Bile

                             III.      Region of alimentary canal where the juice is secreted                      (1mk)

        Duodenum.rej small intestines

         

         

         

         

         

                 b)          Label two test tubes E and F. place 2cm3 of liquid K2 into each. Add a drop of iodine solution into each test tube

        (i)        Record your observations                                                          (1mk)

            Iodine solution changes from brown to blue-black

        (ii)       Suggest the identity of liquid K2                                                     (1mks)

            Starch solution

        (iii)      Cut out a cube whose sides are 1cm from the irish potato provided. Crush the cube to   obtain a paste and place the paste in the test tube labeled E. Leave the set up for at least 30minutes

                        Record your observations                                                              (2mks)

        Content of F remain unchanged/blue black colour in E disappears/fades/change to pale/light yellow/light/light brown/orange

                        Account for the results in (b) (iii) above                                           (2mks)

        Enzyme /amylase in potato breaks down starch/converts/hydrolyse/changes/digest starch into maltose/reducing sugars/simple sugars that do not give a blue black colour with iodine.