Biology Paper 3 Questions and Answers With Confidential - Kapsabet Mocks 2020/2021

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Apart from the usual laboratory apparatus and fittings each candidate will require the following;

  • Germinating bean seed R1 (About six days required to prepare this)
  • Dry bean seed R2
  • Bean/pea (legume) pod R3
  • 2 fresh dicot leaves (medium size) U*
  • 2 fresh eucalyptus leaves W*
  • Photos of two different cervical vertebrae
    • P1, P2 and S (in the question paper)
  • (To be provided to each student)*
    • Scalpel
    • Means of timing (wall clock)
    • Pair of forceps
    • 2* Boiling tubes
    • 100ml beaker
    • Hot water bath/source of hot water
    • Graph paper



Topic objective Content Expectation Marks
germination Drawing
Conditions for germination -Physiological process
support Characteristics of vertebrae 2 Cervical vertebrae Distinguishing features
Identify views
ecology Adaptation of leaves Gaseous exchange (counting bubbles), Calculate surface area  


  1. You are provided with specimens R1, R2 and R3 representing different stages of plant development. Study the specimen carefully and answer questions relating to them.
    1. The chart below shows relationship between the specimens.


      1. Identify the process labeled I (1 Mark)
      2. State one internal and one external conditions necessary for the process identified in i) above. (2Marks)
      3. Name the
        Stage of development R2 (1Mark)
        Process immediately before R3 in process III (1 Mark)
    2. Dissect specimen R3 longitudinally and open it out.
      1. Make a drawing of the section and label it (5Marks)
      2. Describe two adaptations of the specimen to is functions (4Marks)
  2. Specimens U and W have been obtained from different plants.
      1. Observe the leaves and differentiate them in reference to the following characteristics; (2 Marks)

        i) Shape    
        ii) Texture    

      2. Using apparatus and materials provided, determine the average surface area of each leaf. (4Marks)
      1. Draw two 1cm2 squares across the midribs of each the four leaves, two of each U and W.
      2. Add some warm water to fill two thirds of a boiling tube.
      3. Insert one of leaves U, rolled, with the lower surface facing outward.
      4. Immediately begin counting the bubbles released on lower surface, within the two squares for 1 minute.
      5. Repeat the procedures i) – iii) for the second leaf U
      6. Repeat the procedure for the two leaves W
      7. Record your results in the table below (4Marks)

        Leaf Number of bubbles on Lower surface Average for the marked area.
        W   1   

      8. Comment on the observation made on the upper surfaces of the two types of leaves (1 Mark)
    3. Calculate the average number of bubbles per cm2 for each leaf type. (4Marks)
      1. Leaf type U
      2. Leaf type W
      1. Deduce a suitable habitat for plant type W (1Mark)
      2. Give a reason for your answer (1Mark)
  3. The photos provided for this question are of bones P and S from the same mammal. P1 and P2 are photos of the same bone from different views. Study the photographs and answer the questions that follow.



    1. Identify the bones in the photos. Give a reason for each your answers. (4 Marks)
    2. Name the parts labeled A, B and C (3 Marks)
    3. What view of the bone is presented in photo P2? (1 Mark)
    4. Identify one similarity and one difference between bones P and S (2 Marks)
      1. Similarity
      2. Difference

Marking Scheme

      1. germination
        • Internally: embryo maturity/sufficient hormones and enzymes/ adequate food store/ viability;
        • Externally: optimum temperature/water/oxygen;
      3. Seedling
        Double Fertilization
      1.  bio3m1b
        • Seeds: dispersed for propagation of the plant
        • Pericarp: protection of immature seeds, lines of weakness/sutures open up when R3 matures and dries

      1.   U W
        Shape Trifoliate/ovate  Lanceolate 
        Texture Coarse/rough
      Leaf Number of bubbles on Lower surface Average for the marked area.
      1) 2+3 = 5

      Accept values below 10
      e.g. 5.5=6

      2) 3+3 = 6
      W   1) 10+12 = 22  Accept values above those for U
      2) 9 + 14 = 23

      vii) No bubbles observed for both types of leaves due lack of stomata on the upper surface
      1. Number of bubbles per cm2 = 6/2 = 3;
        Hence average number of bubbles produced by U in 1 minute
        = 11x ½ x total surface area of leaf U;

      2. Number of bubbles per cm2 = 22/2 = 11;
        Hence average number of bubbles produced by U in 1 minute
        = 11x ½ x total surface area of leaf W;

      1. Marshland/ soil with a lot of water/ water logged area/ river side
      2. High rate of water lose can be supported in this habitat;
      1. P. Atlas vertebra
        Presence of facets of articulation with condyles of the skull on anterior end
      2. S Typical Cervical vertebra
        Presence of branched transverse processes or cervical ribs
      1. A ….Transverse process
      2. B….Vertebraterial canal/ Atlantal foramen
      3. C …Lamina;
    3. Dorsal view
      1. Similarity
        -large neural canal
        -transverse process present
      2. Difference

        Cervical Absent Present
        Transverse processes: Wide/ wing like Branched;
        Neural spine: Reduced/ non-existent Prominent;
        Centrum: None Large;


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