KCSE 2019 Biology Paper 3 Questions and Marking Scheme with Confidentials

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  1. You are provided with specimens F and G, obtained from different plant from different plant species. Observe them together with photographs E and H and answer the questions that follow
    Note: Do not destroy specimens F and G as you will need them for question 2
    q1 bio p3 2019
    1.  
      1. State how plants represented by specimen F and photographs E and H protect themselves.

        Specimen F (1 mark)
        ...........................
        ...........................

        Photograph E (1 mark)
        .........................
        .........................

        Photograph(1 mark)
        ......................... 
        .........................
      2. State the likely habitat of each of the plants in (a) (i), giving a reason in each case.

        Specimen F (2 marks)
        Habitat............
        Reason............

        Photograph E (2 marks)
        Habitat.............
        Reason.............

        Photograph H (2 marks)
        Habitat...............
        Reason...............

    2. Examine the leaves of specimen G.
      1. Describe two observable features of these leaves that help the plant conserve water. (2 marks) 
      2. Besides leaf structure, explain two mechanisms that help the plant in (b) (i) above not to dry up during the dry season. (2 marks)
  2. You are provided with specimens labelled J and K in addition to F and G and photograph E and H (used in question 1).
    1. Follow the dichotomous key below to identify E, F, G, H, J and K. I.
      1. (a) Leaf margin smooth............................  Go to 2 
        (b) Leaf margin serrated/rugged ................ Go to 3
      2. (a) Leal parallel-veined ..............................   K
        (b) Leaf net-veined or veins not showing...... Go to 4
      3. (a) Leaf with thorny edges .........................   H
        (b) Leaf edges not thorny ........................... Go to 5
      4. (a) Leaf large ............................................  G
        (b) Leaf tiny ............................................... E
      5. (a) Leaf on thorny stem ............................... F 
        (b) Leaf not on stem .................................... J

      Fill the table below, indicating the steps used to identify the leaves of each specimen or photograph. (6 marks)
       Leaf  Steps followed
       E  
       F  
       G  
       H  
       J  
       K  
    2.  
      1. Besides Ical features found in the dichotomous key above, state two other features that can be used to identify leaves. (2 marks)
      2. State the complementary characteristics that define the leaf features stated in (b) (i). (2 marks)
    3. The habit of a plant in its environment is referred to as being a tree, shrub or herb, depending on its height.
      Suggest the habits of the plants from which specimen F and photograph H were obtained (2 marks)
  3. You are provided with specimens L and M which are types of teeth from the same mammal. Observe these specimens together with photographs N and P and answer the questions that follow.
    1.  
      1. With a reason in each case, name the type of tooth represented by specimens L and M.

        Specimen L (2 marks)
        Name: ..............
        Reason ...........

        Specimen M (2 marks)
        Name: ...............................
        Reason .....
      2. Draw and label specimen L. (2 marks)
      3. State two functional differences between specimens L and M.
    2. State the diet of the mammals from which photographs N and P below were obtained, giving a reason in each case.
      q3 bio p3 2019
      1. Photograph N (2 marks)
        Diet .......
        Reason .......
      2. Photograph P (2 marks)
        Diet
        Reason ...........
    3.  
      1. Name the joint labelled K on photograph P. (1 mark)
      2. Explain two features of the joint named in (c) (i) above that makes it adapt to its function (2 marks)

Confidential

  1. Besides other laboratory fittings and equipment, cach candidate will require the following:
    1. A twig with at least three leaves from a thorny lemon tree, labelled F
    2. A twig with at least three leaves from a mango tree, labelled G
    3. A Kale (Sukuma wiki) leaf, labelled J
    4. A portion of creeping grass with at least three leaves/leaf sheaths, labelled K
    5. One incisor tooth, labelled L
    6. One molar or premolar tooth, labelled M
      Note: Collect all plant specimens a day before the examination
      Specimens L and M should be obtained from the same mammal.

Marking Scheme

  1. You are provided with specimens F and G, obtained from different plant from different plant species. Observe them together with photographs E and H and answer the questions that follow 
    Note: Do not destroy specimens F and G as you will need them for question 
    1.  
      1. State how plants represented by specimen F and photographs E and H protect themselves.

        Specimen F (1 mark)
        • Has thorns/spines/prickles/needle-like structure that prick/injure/inhibit/harm/orevent herbivores/mammals/animals
        • Shiny/glossy to reflect light to reduce water loss/transpiration
        • Leaves fold to reduce transpiration/water loss rej. folding alone

          Photograph E (1 mark)
        • Plant normally produce a (white) unpleasant/poisonous/unpalatable fluid(latex, substance, mucilage, sap)
        • Succulent(stem) to reduce water loss/transpiration/dehydration
        • Has tiny/small/absence of leaves to reduce transpiration

          Photograph H (1 mark)
        • Plant has thorny/prickles/pricks/spines on leaves that prick herbivores/mammals/animals
        • Produces unpleasant/poisonous/irritating/bitter/harmful/distasteful/unapalatable fluid
      2. State the likely habitat of each of the plants in (a) (i), giving a reason in each case.

        Specimen F (2 marks)
        Habitat........Terrestial habitat with adequate/moderate/average rain/water availability/well-watered soils
        Reason............Leaves fold to conserve water during drought/dry season; has medium/average sized leaves; glossy/shiny leaves to reflect away light hence reducing water loss

        Photograph E (2 marks)
        Habitat.............Arid/Semi-arid/dry land/desert/semi-desert habitat with inadequate water supply rej.dessert
        Reason.............Thick/succulent/fleshy stem(that stores water/fluid/mucilage); leaves reduced in size/number/absence of leaves/tiny leaves rej. needle-like leaves

        Photograph H (2 marks)
        Habitat...............Arid/Semi-arid/dry land/desert/semi-desert 
        Reason...............Plant leaves are thick/succulent/fleshy (that stores water/fluid/mucilage); plant leaves with thick cuticle

    2. Examine the leaves of specimen G.
      1. Describe two observable features of these leaves that help the plant conserve water. (2 marks) 
        • Shiny/glossy leaf surface that reflect light reducing water loss/dehydration/dessication
        • Thick/waxy cuticle  to reduce (the rate of cuticular) transpired/water loss/dehydration/drying
      2. Besides leaf structure, explain two mechanisms that help the plant in (b) (i) above not to dry up during the dry season. (2 marks)
        • Has long tap rots/deep rooted/deep roots to reach more water down the surface.
        • Plant Shed leaves during drought I dry season (to recluce the surface area exposed for) transpiration
          Accept - Leaf fall rej. Shedding of all the leaves.

  2. You are provided with specimens labelled J and K in addition to F and G and photograph E and H (used in question 1).
    1. Follow the dichotomous key below to identify E, F, G, H, J and K. I.
      1. (a) Leaf margin smooth............................  Go to 2 
        (b) Leaf margin serrated/rugged ................ Go to 3
      2. (a) Leal parallel-veined ..............................   K
        (b) Leaf net-veined or veins not showing...... Go to 4
      3. (a) Leaf with thorny edges .........................   H
        (b) Leaf edges not thorny ........................... Go to 5
      4. (a) Leaf large ............................................  G
        (b) Leaf tiny ............................................... E
      5. (a) Leaf on thorny stem ............................... F 
        (b) Leaf not on stem .................................... J

      Fill the table below, indicating the steps used to identify the leaves of each specimen or photograph. (6 marks)
       Leaf  Steps followed
       E  1a, 2b, 4b;
       F  1b, 3b,5a;
       G  1a, 2b, 4a;
       H  1b, 3a;
       J  1b, 3b, 5b
       K  1a, 2a
    2.  
      1. Besides leaf features found in the dichotomous key above, state two other features that can be used to identify leaves. (2 marks)
        • Leaf apex(tip)
        • Leaf base
        • leaf texture
        • leaf colour
        • leaf attachment
        • leaf type
        • leaf lamina
        • leaf thickness
        • Nature of leaflets
        • Arrangement of leaflets
        • Nature of leaf surface
          rej leaf arrangement; leaf structure
      2. State the complementary characteristics that define the leaf features stated in (b) (i). (2 marks)
        • Leaf apex(tip) - pointed or rounded/lobed/absence of tip
        • Leaf base - absence of petiole/petiole/sheath
        • Leaf texture- smooth/rough/hairy/not hairy
        • Leaf colour - Green or any other color of leaves
        • Leaf thickness - Thin/thin flehy/succulent/not flossy
        • leaf type - simple or compound
    3. The habit of a plant in its environment is referred to as being a tree, shrub or herb, depending on its height.
      Suggest the habits of the plants from which specimen F and photograph H were obtained (2 marks)
      • F - A tree
      • H - A herb
  3. You are provided with specimens L and M which are types of teeth from the same mammal. Observe these specimens together with photographs N and P and answer the questions that follow.
    1.  
      1. With a reason in each case, name the type of tooth represented by specimens L and M.

        Specimen L (2 marks)
        Name: ..............Incisor (tooth) rej wrong spelling by underlining
        Reason ...........chisel- shaped/chisel-like/wedge-shaped/sharp edged rej. sharp alone

        Specimen M (2 marks)
        Name: ....................Molar (tooth)
        Reason ...................Have three/four roots; Broad/ridged surface/with cusps/with ridges 
        OR 
        M - premolar(tooth)
        • Has two roots
        • Broad/ridged surface/surface with cusps/with ridges
      2. Draw and label specimen L. (2 marks)
        specimen L bio p3
      3. State two functional differences between specimens L and M.

         L(Incisor)  M(Molar/premolar)
         Is used for cutting/gripping/biting food/vegetation(against the horny pad on the upper jaw)  is for crushing/chewing/grinding food/vegetation into smaller pieces before swallowing
         For holding prey/shearing meat from the bones  for chewijng/grinding/crushing bones/flesh
    2. State the diet of the mammals from which photographs N and P below were obtained, giving a reason in each case.
      1. Photograph N (2 marks)
        Diet .......Vegetation/grass/plant materials/vegetables OWTTE
        Reason .......has (rough/horny/hard) pad in the upper jaw/ no incisor in the upper jaw(upon which vegetation is cut); Has diastema/absence of canines for the tongue to easiy manipulate grass/food/plant materials; Absence of canines to (facilitate sideways movement)
      2. Photograph P (2 marks)
        Diet .....flesh/meat
        Reason ...........(large/long/curved) sharp/sharp-pointed/pointed canine; presence of carnassial teeth
    3.  
      1. Name the joint labelled K on photograph P. (1 mark)
        • Suture(S) reject wrong spelling underlining then mark (ii)
      2. Explain two features of the joint named in (c) (i) above that makes it adapt to its function (2 marks)
        • Bones interlock forming strong joints that form a hard cranium/skull that protect the delicate brain
        • Bones interlock/fits into each pther forming/making strong joints to protect the delicate brain
        • Immovable/fixed joints/tightly holding bones in place to protect the brain

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