Biology P3 Questions, Answers and Confidential - Mangu High School Trial Mock Exams 2021/2022

QUESTIONS

1. You are provided with specimen labeled E, examine specimen E
   1. Giving reasons, identify the type of the fruit? (2mks)
   2. Cut a transverse section through specimen E, make a well labeled diagram (5mks)
   3. State the type of placentation of E (1mk)
   4.                  
      1. Name the agent of dispersal for E (1mk)
      2. State how E is adapted to its mode of dispersal (2mks)
   5. Squeeze out the juice from specimen E into test tubes and using the regents provided carry out food test and fill in the table below (6mks)
      

      Food test	Procedure	Observation

2. Study the photographs and answer the following questions.
   
   
   1. The photograph in Plate 5 shows the germination process in a species of legume.
      1.                            
         1. Name the type of germination shown in the photograph. (1 mark)
         2. Give a reason for your answer. (1 mark)
      2. Other than germination the seedling has shown some responses.
         1. Name two responses shown in the photograph. (2 marks)
         2. State one survival value of each of the response named above. (1 mark)
   2. Examine the photograph in Plate 6 and Plate 7 which show different essential parts of a flower of a species on two different plants.
      1. Name the flower parts shown in Plate 6 and Plate 7. (2 marks)
      2.                
         1. Name the phenomenon described in the statement above. (1 mark)
         2. Explain the significance of the phenomena stated in (a)(i) above. (1 mark)
      3.                        
         1. State the mode of pollination of the flower shown in the photograph. (1 mark)
         2. Give a reason for your answer. (1 mark)
3. The diagrams below represent body parts of some organisms (animals). Study them and answer the question that follow.
   
   
   1.                      
      1. Suggest the type of food eaten by organisms with the parts labeled A, B, C and F (4 mrks)
      2. With reasons, suggest the likely habitat of the organism from which the parts labeled D and E were obtained. (4 mrks)
   2.                
      1. Suggest the type of evolution that is exemplified by the organisms labeled D, E and F. Give reason for your answer. The type of evolution (2mks)
      2. Suggest the significance of the above named type of evolution for the organism (2mks)

MARKING SCHEME

1.                      
   1.                                                
      
      Drawing – 1mk
      Accuracy – 1mk
      Labelling – 6/2 = 3mks
      Magnification = 1mk
      Total = 6mks
   2. A berry / Hesperidium;
   3.            
      1. Animal Dispersal
      2. – Succulent endocarp / juicy endocarp;
         - Seeds resistant to digestions ;
         - Scented ;
         - Bright coloured exocarp;
   4.              
      1. Animal
      2. -Fleshy/ juicy pericarp to attract the animal
         - Brightly coloured epicarp to attract the animal
         - Indigestible seed coats to avoid digestion by enzymes
   5.                               
      

      Food substance	Procedure	Observation	Conclusion
      Vit . C (Ascorbic Acid)	- Put 2cm3 given vol. of   DCPIP in test –tube. - Add juice / test substance	DCPIP decolourised	- Vit C present
      Reducing sugar	- Put test substance in t.tube - Add Benedict soln; - Boil;	Colour changes to yellow / orange / red.	Reducing sugar present
      Proteins	To the juice add sodium Hydroxide Solution then copper (II) sulphate Solution	Blue colour is retained	Proteins absent

2.                                                  
   1.  
      1.                          
         1. epigeal
         2. - cotyledons are above the ground
      2.                  
         1. - positive hydrotropism in roots
            - positive phototropism in shoot.
         2. Positive phototropism
            Light causes lateral migration of auxins away from the light side, towards the darker side; high auxin concentration stimulates growth in the shoot; thus the cells on darker side grew and elongated faster than the cells on the illuminated side; causing the curvature towards light;
         3. Provides yield energy required by the cell for various functions;
            Positive hydrotropism.
            Water causes auxins to migrate towards the side with water / moisture, auxin, are positively hydrotropic; low auxin concentration stimulates growth in roots, auxin high concentration inhibit growth in roots; the cells on the side away from the water grow and elongated faster; leading to curvature towards water.
         4. Phototropism enables plants (shoot) to obtain optimum light for photosynthesis.
            Hydrotropism by roots enables plants to absorb water and mineral salts for metabolic processes.
   2.                  
      1. plate 6 - stamen plate 7 - pistil
      2.                  
         1. dioecium
         2. facilitates pollination leading to variation within the species and increase in hybrid vigour.
      3.                        
         1. wind pollination
         2. Small incospicuous bracts; that are dull coloured
      4.                    
         1. cross pollination.
         2. - male and female parts occur in different plants.
            - the plant pollen grains are sterile to the stigma of the same plant
3.              
   1.                            
      1.                                           
         

         Specimen	Food	Reason
         A	Aquatic matter and small invertebrates	Wide shovel shaped beak
         B	Nectar	Long, thin beak
         C	Nuts	Short, thick strong beak
         F	Flesh	Strong sharp curved talons /claws

      2.                                
         

         Part	Habitat	Reason
         D	Aquatic	Webbed feet for swimming/wadding
         E	Tree branches	Long feet/toes for grasping/perching

   2.                       
      1. Divergent evolution; (4mks)
         Reason: Similar basic structure and embryonic origin but modified into different forms / appearance;
      2. Enable the organisms / animals to utilize different ecological niches; to avoid competition for food; (2mks)

CONFIDENTIAL

BIOLOGY REQUIREMENTS PRACTICALS
INSTRUCTIONS TO SCHOOLS
(Care must be taken to ensure that the information herein doesn’t reach the candidates)
Candidates require the following in the working Bench

• Ripe orange fruit- labeled E (Each candidate)
• Scalpel
• 1%Cuso4
• 10%NaoH
• Distilled water/tap water
• Test tube rack
• Test tube holder
• 0.01% Dichlorophenol Indophenol (DCPIP) Solution
• Three clean test tubes
• Means of labeling
• Source of heat
• Benedict’s solution
• Tripod stand
• Wire gauze
• 50ml glass beaker
• Water bath