Biology Paper 3 Questions and Answers - Alliance Mock Examinations 2022

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QUESTIONS

  1. You are provided with specimen labeled M. Crush it using pestle and mortar, add some distilled water to get fine solution. Label four clean test tubes: A, B, C, and D. Put about 4ml of the solution into each of the four test tubes.
    1. To solution in test tube A, add some few drops of iodine. Shake the solution to mix well. Pour some little solution onto a white tile.
      1. Record your observation.
      2. Account for your observations in a) (i) above
    2. Into solution in test tube B, add about 2ml of Benedict's solution. Place it in a boiling water bath.
      1. After about 3 minutes, record your observation
      2. What is your conclusion from observation in b) i) above?
    3. For the remaining test tubes: -
      To test tube C, add about 3ml of solution labeled K. To test tube D, add about 3ml of solution K and about 2ml of solution labeled L. Place both test tubes C and D in a water bath. Maintain the water bath at 37°C. Allow it to stand in the water bath for 30 minutes. After 30 minutes, remove the test tubes. Add about 2ml of Benedicts solution to each test tube and shake well. Place the two test tubes in a boiling water bath. After about 5 minutes record your observations in the table below.
      Test tube
      Observation
      Conclsion
      C    
      D    
    4. Account for your observations in the test tubes C and D.
    5.    
      1. Why was set up placed at 37°C?
      2. Suggest identity of solutions K and L
  2. The photographs below are of the same mammalian vertebra showing two views of the same bone. Examine them carefully.
    1
    1.       
      1. Identify the vertebrae in photograph
      2. Name part X
      3. State the function of part X
    2. State the functional difference between a tendon and a ligament
    3. Name the views of the vertebrae above?
    4. State a common role of the parts labeled Y and Z.
    5. What are the differences between bones A and B?
    6. The photographs below illustrate a response in plants. Study it carefully and answer the questions that follow.
      2
      1. Identify the type of response illustrated above.
      2. Explain how the structure above is formed.
      3. Besides the structure above, name other two support structures in plants.
  3. You are provided with specimen D. (a)
    1.      
      1. Cut off the petiole, about 1.5 cm from the end where the leaf attaches to the stem.
      2. Carefully make several thin cross sections through the piece obtained in (a)) above, using a sharp razor blade or scalpel.
      3. Put the sections obtained in water on a Petri dish. (iv) Mount the thinnest section(s) on a glass slide, add a drop of iodine solution provided.
      4. Observe the section(s) using a hand lens, then draw a labelled diagram of the section observed.
    2. Account for the following features of specimen D.
      1. Extensive network of veins
      2. Tough leaf blade
      3. Strong and extended petiole
    3. State with reason, the class of plants from which the specimen was obtained.
      Class: (1mark)
      Reasons: (1mark)
  4. Explain why the following procedures were necessary during the preparation of the sections for observation.
    1. Putting the sections in water on a Petri dish.
    2. Using a sharp scapel/razor blade.
    3. Adding iodine solution to the section.
    4. Cutting very thin sections.


MARKING SCHEME

  1.      
    1.    
      1. Solution turns blue-black in colur
      2. this indicates presence of starch in the solution
    2.      
      1. blue colour persists
      2. reducing sugars absent
    3.   
      Test tube Observation Conclsion
      C colour changes to form blue to yellow to orange and then brown reducing sugars present
      D blue colour persists reducing sugars absent
      the starch solution was not hydralised, hence absence of reducing sugars after 30 minutes; solution prevented the hydrolysis by K since it determined it
    4. starch solution was converted/ hydralized to reducing sugars; the 30 minutes allowed hydrolysis of starch by solution K
    5.    
      1. It is the optimum temperature for enzymes action
      2. K - Analyse enzyme/lactase
        L - Hydrochloric acid; acc. enzyme inhabitat
  2.     
    1.    
      1.  atlas
      2. lumbox
    2.     
      1. articulating facet
      2. for articulation with the axis
    3. ligament - holds bones together at a joint
      tendon - attaches skeletal muscles to bones
    4. A - Postenor/dorsal
      B - Attenor
    5. forms surface for muscle attachment

    6. A B
      has vertebrial canals
      small neural spine
      lacks metapophy
      lacks vertebraterial canals
      large neural spine
      has metapophyses and amapophyses
      1. Thigmotropism
      2. contact causes lacteral migration of auxins to accumulate on the outer part which is not in cataclistis
        causes faster elongation of cells in the inner part then the outer part. this makes the short to keep coiling around the support object
      3. xylem tissues
        turgid paradym
        coltendymes
  3.    
    1.    
      3
    2.      
      1.  enhance transportation of water/ nutrients/ organic food substances and mineral salts
      2. enhance support
        prevent leaf from folding
        thick water cuticles to minimize water loss
        keep leaf open to allow maximum reception of liquid for photosynthesis
      3. to provide support/attach firmly/attach strongly
    3. class - dicotyledon
      reasons - presence of pitch
      broad leaf/leaf blade
      presence of solid leaf /stalk
    4.       
      1. maintains shape of cells/sections/tissues
        keep cells turgid/ cells not to dry/ cells not to die
        prevents dehydration
      2. avoiding damaging cells during coating/ distort of cells/ tissues
      3. enhance clarity/ proper visibility
      4. allow light to pass through
        for every diffusion of iodine solution/to stain

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