BIOLOGY PAPER 3 - 2019 LANJET JOINT MOCK EXAMINATION

1. You are provided with the following materials and reagents.
   A straight portion of raw pawpaw, labelled D
   Two petri dishes, a scalpel/sharp razor blade, two beakers containing liquids A and B
   A measuring cylinder, A stop watch/access to a wall clock, Means of labeling
   1. Label the two petri dishes, A and B
   2. Place 30cm³ of liquid A into petri dish A and 30cm³ of liquid B into petri dish B
   3. Using the scalpel, prepare four thin, straight flat strips from the raw pawpaw peel
   4. Each strip should measure about 4cm by 2mm as illustrated below
   5. Immerse two strips in petri dish A and the other two in petri dish B and leave the set ups undisturbed for 10 minutes.
      1.  
         1. State your observations in petri dish A and B after 10 minutes
            Petri dish A                                                                                                                               (1mk)
            Petri dish B                                                                                                                              (1mk)
         2. Account for the observations made in (a) (i) above
            Petri dish A                                                                                                                            (2mks)
            Petri dish B                                                                                                                             (2mks)
      2. Describe the nature of liquids A and B in relation to the sap in the pawpaw peel used in the experiment
         Petri dish A                                                                                                                               (1mk)
         Petri dish B                                                                                                                               (1mk)
      3. With reference to the observations made, compare the nature of the outer and inner surfaces of the pawpaw peel                                                                                                                 (2mks)
      4.  
         1. Name the cell structure responsible for the observations made in this experiment       (1mk)
         2. Explain how the cell structure named in (d) (i) above works to bring about the observations made                                                                                                                                        (1mk)

2. Study the specimens provided then answer the questions below.   
              
   1. Name the parts labeled U1, W1, W2 and V3                                                            (4mks)
   2.  
      1. Suggest the mode of dispersal of the specimen labeled U                                      (1mk)
      2. Give a reason for your answer in b (i) above.                                                         (1mk)
   3.  
      1. suggest the mode of dispersal of the specimen labeled X.   (1mk)         
      2. Give a reason for your answer in C (i) above                                                       (1mk)
   4. The Photograph shown below was taken from a damp tree bark. It has organism Q on the surface. Study it then answer the questions.
      
      
      1. Name organism labeled Q…………………………………..……………………….....(1mark)
      2. Name two organisms that make up Q…………………………..…………………....(2marks)
      3. Suggest the feeding relationship between the identified organisms in d (i) above explaining the role of each in the relationship.             (1mark)
      4. Identify the two possible Kingdoms represented by organism Q.                              (2marks)

3. Study photographs shown below then answer the questions
   
   
   1. State the type of evolution represented by structures Q1, R1 and S1.                                        (1mark)
   2. Explain the type of evolution identified in (a) above.                                                             (1mark)
   3. Give the evolution term used to describe structures;
      1. Q1, R1 and S1.                                                                                                          (1mark)
      2. A1, B1 and C1.                                                                                                           (1mark)
   4. what type of evolution is illustrated by the limbs (A1, B1 and C1)?                                        (1mark)
   5.  
      1. Name classes for organisms labeled Q, R and S.                                                                                 
      2. Give two observable reasons for your answer for class S.                                            (2marks)
   6.  
      1. suggest the diet of animals B and R.                                                                                   
      2. How is beak of animal B adapted to its function?                                                                (2marks)

MARKING SCHEME

1.  
   1.  
      1. Petri dish  A; Bends to form a ring like strip
         Petri dish  B; flattens feels flabby
      2. petri dish A;  strips placed in hypotonic solution  through cortical cells takes water by osmosis , cells become turgid create a bend on strip
         Petri dish B;strips placed in hypertonic solution  through cortical cells loses water by osmosis cells become flaccid
   2. petri dish A ; Hypotonic solution
      Petri dish  B; Hypertonic solution
   3. outer surface, epidermis impermeable to water
      Inner surface; cortex permeable to water
   4.  
      1. cellulose
      2. cellulose material do not stretch  
2. U1-funicle
   W1-mesocarp
   W2-Axile placenta
   V3-Parietal placenta
   1.  
      1. self explosive mechanism
      2. has lines of weakness on pod, sutures
   2.  
      1. animal
      2. has hooks for attachment to animal’s fur or hair
   3.  
      1. Lichen
      2. symbiosis; algae provides photosynthetic tissues; fungi provides rhizoids for absorption of water and mineral salts
      3. –Fungi and Protoctista/ protista
3.  
   1. convergent evolution
   2. Different structures with different embryonic origins are modified to perform similar functions
   3.  
      1. analogous structures
      2. Homologous structures
   4. divergent evolution/ adaptive radiation
   5.  
      1. Q…..…Insecta;         R……Aves;          S……Mammalia
      2. has pinnae;      has fur covering body
   6.  
      1. B………flesh;      R……nectar from flowers
      2. Strong, curved and sharp; to rip flesh from bones.