Biology Paper 3 Questions and Answers - Sukellemo Joint Mock 2020/2021

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SUKELLEMO JOINT MOCK
Kenya Certificate of Secondary Education
BIOLOGY PAPER 3
(Practical)
1¾  HOURS

Instructions to Candidates

  • Answer all the questions in the spaces provided.
  • Spend the first 15 minutes of the 1¾  hours to read through the paper carefully before commencing your work.
  • One may be penalized for recording irrelevant information and for incorrect spelling, particularly of technical terms.
  1. You are provided with two pieces of plant material labelled specimen D. using a scalpel cut a longitudinal section half way through the middle of each piece as shown in the diagram below.
    BioSukPP3Q1
    1. Place one piece in solution labelled ?1 and the other piece in the solution labelled ?2. Allow the set up to stand for 30 minutes.
      1. Record your observation (2 marks)
        L1
        L2
    2. Examine the pieces.
      1. Record other observations besides those made in (a) (i) above. (3marks)
      2. Account for the observation in (a) (i) above. (5 marks)
      3. Account for the observation in (b) (i) above. (3marks)
  2. You are provided with photographs of specimen M and N. Examine them.
    BioSukPP3Q2
    1. Identify the bones. (2marks)
      M
      N
    2. Name the parts labeled X and Y. (2marks)
      X
      Y
    3. State three significance of the part labelled Y. (3 marks)
      Y
      1. .
      2. .
      3. .
    4. Calculate the actual size of specimen labelled M. (Show your working). (3marks)
    5. Name the part of the mammalian body from where the specimens were obtained. (1mark)
    6. State with reasons the type of joint formed at the proximal and distal end of M (4marks)
      Proximal end
      Reason
      Distal end
      Reason
  3.  
    1. The photographs below are for specimen labelled P,Q and R.
      BioSukPP3Q3A
      1. State with a reason the class to which specimens P belongs. (3 marks)
        P
        Reason
      2. What type of germination is exhibited by Q? (2marks)
        Q
        Give a reason for your answer.
      3. Name the parts labelled U and V on the photographs above. (2marks)
        U
        V
    2. The diagrams below shows the photographs of specimens A and B
      BioSukPP3Q3B
      1. Using observable features only, state the class to which the specimen in photographs A belongs. (1mark)
      2. Give a reason for your answer. (1mark)
      3. State the habitat in which the specimen in photograph B is found. (1mark)
      4. Identify the stage of development of the specimen in photograph B. (1mark)
      5. Give a reason for your answer in (b) (iv) above. (1mark)

CONFIDENTIAL

  1. 2 Pieces of Tradescantia zebrina stem (4 cm each) – labelled D
  2. 20 ml of Solution labelled L_1 – distilled water in 50 ml beaker
  3. 20 ml of Solution labelled L_2 - 2 % salt solution in 50 ml beaker.
  4. Scalpel blade.

MARKING SCHEME

  1. You are provided with two pieces of plant material labelled specimen D. using a scalpel cut a longitudinal section half way through the middle of each piece as shown in the diagram below.
    BioSukPP3Q1
    1. Place one piece in solution labelled ?1 and the other piece in the solution labelled ?2. Allow the set up to stand for 30 minutes.
      1. Record your observation (2 marks)
        L1 - The stem is hard/firm/stiff;
        L2 - The stem is soft;
    2. Examine the pieces.
      1. Record other observations besides those made in (a) (i) above. (3marks)
        • L1 The slit opens wider; and bends outwards towards the epidermis/cuticle;
        • L2 The slits remain close together;
      2. Account for the observation in (a) (i) above. (5 marks)
        • Solution Lis hypotonic to the cell sap; water moved into the stem cells by osmosis; the cells of the stem became turgid;
        • Solution L2 is hypertonic to the cell sap; water moved out of the cells by osmosis making the cells of the stem become plasmolysed and the tissue soft;

      3. Account for the observation in (b) (i) above. (3marks)
        • L1 The cells in the inner surface/cut surface enlarge more because they took in more water by osmosis; than the outer cells which have cuticle; in ?? the cells in the cut surface lost more water by osmosis than the outer cells with cuticle;

  2. You are provided with photographs of specimen M and N. Examine them.
    BioSukPP3Q2
    1. Identify the bones. (2marks)
      • M Humerus;
      • N Ulna & radius;

    2. Name the parts labeled X and Y. (2marks)
      • X Olecranon process;
      • Y Sigmoid notch;

    3. State three significance of the part labelled Y. (3 marks)
      Y
      1. Attachment of muscles/tendons;
      2. Formation of hinge joint ;( with adjacent bone)
      3. prevents overstretching of the forearm backwards

    4. Calculate the actual size of specimen labelled M. (Show your working). (3marks)
      • Actual length = 22.6 ± 0.1cm
      • Drawing length = 11.3 ± 0.1cm
      • Magnification=Drawing length/actual length=11.3/22.6;=11cm/actual =22cm;

    5. Name the part of the mammalian body from where the specimens were obtained. (1mark)
      • Forelimb/arm/legs; acc humerus –upper arm; Ulna and radius lower arm;

    6. State with reasons the type of joint formed at the proximal and distal end of M (4marks)
      Proximal end - Ball and socket;
      Reason - Head shaped like a ball/rounded head/round head/Allows movement in all planes/360°;
      Distal end - Hinge joint;
      Reason - Allows movement in only one plane/presence of a groove/presence of condyles/troches which articulates with the sigmoid notch;
  3.    
    1. The photographs below are for specimen labelled P,Q and R.
      BioSukPP3Q3A
      1. State with a reason the class to which specimens P belongs. (3 marks)
        P Monocotyledonae;
        Reasons Leaves with parallel veins; presence of leaf sheath;

      2. What type of germination is exhibited by Q? (2marks)
        Q Epigeal;
        Give a reason for your answer.
        The cotyledons carried above the soil surface;
      3. Name the parts labelled U and V on the photographs above. (2marks)
        U Hypocotyl;
        V cotyledon;
    2. The diagrams below shows the photographs of specimens A and B
      BioSukPP3Q3B

      1. Using observable features only, state the class to which the specimen in photographs A belongs. (1mark)
        • Insecta;
      2. Give a reason for your answer. (1mark)
        • Presence of six legs/ three body parts/ one pair of antenna;
      3. State the habitat in which the specimen in photograph B is found. (1mark)
        • Dead decaying organic matter;

      4. Identify the stage of development of the specimen in photograph B. (1mark)
        • Larva;

      5. Give a reason for your answer in (b) (iv) above. (1mark)
        • Absence of legs/wings/presence of fleshy protuberances/presence of a hook-like tooth


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