BIOLOGY PAPER 3 - 2019 LAINAKU JOINT MOCK EVALUATION EXAMINATION

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  1. You are provided with:
    -Solution Q
    -Distilled water in 100 ml beaker
    -Visking tubing and two threads
    -Glass rod
    -2 test tubes and two labels
    -Benedict’s solution 10% sodium hydroxide solution and 1% copper sulphate solution.

    PROCEDURE:
    -Tie the visking tubing tightly at one end using the thread and put about 5ml of solution Q. Tie tightly the other end ensuring that there is no leakage.
    -Place the visking tubing in the distilled water in 100ml beaker and support it by tying the thread on a glass rod over the beaker.
    - Allow the set up to stand for 30mins. Observe any changes in the visking tubing.
    -Remove the visking tubing from the distilled water.
    -Using a syringe draw about 5ml of the contents in the beaker labeled distilled water. Put it in the test tube and label it G. Repeat the same procedure to obtain 5ml of solution in the visking tubing, put in another test tube and label it H.
    1. Using the reagents provided, carry out food tests to determine the components in substance G and H and fill the table below.

      Substance

      Food Test

      Procedure

      Observation

      Conclusion

           G

             
             

           H

             
       8marks
    2. Substance Q is a urine sample obtained from a patient in a hospital laboratory. Name two conditions that the patient was suffering from. (2marks)
      1. What physiological activities that took place in the experiment you undertook above.
      2. Account for your answer in C (i) above.                                                                    (2marks)
  2. Study the photomicrographs below and use them to answer questions that follow.
    biology3 q2.sggsh
    1. Identify the type of cell division above.
    2. Give a reason for your answer (i) above.         (1mark)
    3. With a reason identify each stage.                (4marks)

      Diagram

      Stage

      Reason

      D1

      D2

      D3

      D4

         
      The photographs below show two fruits and their half-sections
      biology2 q4.qsns
      1. Through which plane has the sections been cut?                                            (1mark)
      2. State two differences between specimens S and T.                                       (2marks)
      3. With reasons, in each case state the type of fruit and method of dispersals for specimen S and T.           (2marks)

        Specimen S
        Type of fruit:
        Reason
        Method of dispersal
        Reason
                             
        Specimen T                                                                                                                (2mks)
        Type of fruit:………………………………………………………………………..
        Reason:……………………………………………………………………………..
        Method of dispersal:……………………………………………………………….
        Reason…………..………………………………………………………………….
      4. Draw and label a diagram ofcut specimens S.                                      (4marks)
  3. Study the diagrams below and answer the questions that follow.
    biology3 q3ghagshh.qsns
      1. Name the parts labeled A, B, C and D.                                                     (4marks)
      2. State the adaptation of the part labeled A to its function.                      (2marks)
      3. State one function of the part labeled C.                                                            (1mark)
    1. State three adaptations of the part labeled D.                                                     (3marks)


MARKING SCHEME

  1. Substance

    FoodTest

    Procedure

    Observation

    Conclusion

           G

    Reducing

    sugars

    -To 2cm3 Sol. G in a test tube, add equal amount of benedicts solution, heat to boil.

    Colour changes from blue to green to yellow to orange.

    Acc-final colour

    Reducing sugars present

    proteins

    -To 2cm3 of Sol. G add 10% NaOH(aq) followed by 1% of CuSO4 drop by drop

    Blue colour persists/colour of CuSO4r remains

    Proteins absent

          H

    Reducing sugars

    -To 2cm3 of Sol. H in a test tube, add equal amount of Benedict’s solution, heat to boil.

    Colour change from blue to green- yellow-orange

    Reducing sugars present

    proteins

    -To 2cm3 of Sol. H in a test tube, add 10% NaOH(aq )followed by 1%CuSO4 drop by drop

    Purple colour formed/blue colour changes to purple

    Proteins present

    Note:                                                                                                                                                                                  8mks
    Award half a mark for each correct response.
    -Type of test must be correct to score for procedure, observation and conclusion.
    -Spelling of the reagents must be correct, otherwise underline and proceed.
    -If chemical symbols are used, they must be correctly written.
    -Colour sequence must be followed whereby all the colours of the mixture have been stated.
    1. -Diabetes mellitus
      -Albuminuria/proteinuria
      1. -Diffusion and osmosis
      2. -Reducing sugars have tiny molecules which diffuses through the pores in the membrane of the visking tubing; along a concentration gradient; The molecules of the proteins/proteins in solution H are larger and cannot pass through the pores of the visking tubing.
        -Change in size of visking tubing explains movement of water molecules by osmosis.
    1. Mitosis
    2. Chromatids separating and the division ending wiyh two daughter cells
    3. D1  METAPHASE……Chromatids align at the equator of the spindle fibres
      D2..INTERPHASE…..Dense chromatin
      D3  PROPHASE…..Chromosomes visible
      D4….TELOPHASE…..Cell membrane constricting.
      1. Longitudinal
      2. Specimen S has several/many seeds while T has one seed
        S has a fleshy endocarp while T has hard /woody endocarp.
        S has axile placentation while T has basal placentation.

        Specimen S
        Type of fruit; Berry
        Reason: Has numerous seeds which are embedded in a succulent endocarp.
        Method of dispersal: Animals
        Reason: Fleshy/Juicy/ succulent/scented.

        Specimen T
        Type of fruit: Drupe
        Reason: Has one seed which is enclosed with a hard endorcarp.
        Method of dispersal; Animals
        Reason: Fleshy /Juicy /succulent/scented
      3. NOTE:
        The three parts be well labeled; Epicarp,Mesocarp;& Endocarp.
        -To award for labeling consider the following:
        Spellings
        Label lines should touch the part being labeled
        Label lines should be continuous with no arrows at the end
        Label lines should not criss cross
      1. A –Trachea.     B-Bronchus.C-Pleural membrane.               D-Alveoli
      2. –Has rings of cartilage that keep it open
        -has cilia that move mucus and dust particles to the top of the trachea
        -lining secretes mucus, which traps dust particles and micro-organism
        Secretes pleural fluid that lubricates the lungs.
    1. –moist to dissolve gases
      –Thin membrane for rapid diffusion
      –Highly vascularised to maintain a steep concentration gradient for diffusion of gases.
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