Biology Paper 3 Questions and Answers - Maranda Post Mocks 2020/2021

1.  
   1. You are provided with solutions labeled Q and S and a powder labeled P together with a filter paper. Using the reagents provided, test fot the presence of food substance in powder P. Record your work in the table below. (12 marks)
      
      

      Food Tested	Procedure	Observation	Conclusion

   2. State two enzymes required to digest powder P in the alimentary canal in human beings. (2 marks)
2. Photographs S1, S2 and S3 represent specimens obtained from the same animal while photograph S4 represents structure on a part of a plant. Examine them and use them to answer the following questions.
   
   
   1.  
      1. Identify specimen S1 (1 mark)
      2. Name the structures labeled T and R on the photograph. (2 marks)
         
   2.  
      1. Identify bones labeled X, Y and S3. (3 marks)
      2. Identify the part labeled I. (1 mark)
      3. What is the significance of the structure labeled L on the photograph S2. (2 marks)
      4. With reasons, name the type of joint formed at the proximal and distal ends of the speciment S3.
   3. 
       
      1. Name the type of response shown by plant S4. (1 mark)
      2. Explain how the response occured. (2 marks)
      3. Identify strengthening tissues in woody plants. (2 marks)
3. Below is a photomicrograph of a cell. Observe it and use it to answer the questions that follow.
   
   
   1.  
      1. Identify the type of cell. (1 mark)
      2. give reasons for your answer in a) i) above. (1 mark)
      3. Identify the organelle labeled N and Q and state the functions of each in the table. (4 marks)
         

         Organelle	Name	Function
         N
         Q

   2. Account for the number of organelle Q that would be found in sperm cells. (2 marks)

Marking Scheme

1.  
   1.  
      

      Food Tested	Procedure	Observation	Conclusion
      Starch	put 2ml of solution P in a test tube. Add 3 drops of Iodine/ Q solution	brown color of Iodine turns to blue black	Starch present
      Reducing sugars	Put 2ml of solution P in a test tube and add equal amounts of benedict's solution, heat to boil	Blue colour of benedict's solution changes to green-yellow-orange	Reducing sugars present
      Lipids (accept fats/oils)	Rub P on the filter paper or place a drop of solution P on a filter paper, dry over a flame; observe the filter paper against light	No transluscent mark/spot seen	Lipids absent.

   2. Salivary amylase/ptyalin; lactase; maltase
2.  
   1.  
      1. S1 - Scapula
      2. Coracoid process
         Glenoid cavity
   2.  
      1. X - Radius
         Y - Ulna
         S3 - Humerus
      2. I - trochlea
      3.  
         • Prevents overstretching of the forearm (at the elbow)
         • attachment to muscles
      4. Proximal end - Ball & socket; Reason - rounded end / head shaped like a ball (1 mark)
         Distal end - Hinge joint; Reason - presence of a trochlea groove
   3.  
      1. Thigmotropism / Haptotropism
      2. the tendrils came into contact with the hard object, (the contact caused them to coil around the hard object. The part in contact has a lower auxin conc. that the outer part causing auxins to migrate to the side away from contact hence faster elongation)
      3.  
         • Sclerenchyma
         • Collenchyma
         • Xylem tissue
3.  
   1.  
      1. Animal cell
      2. Presence of numerous secretory vesicles
         Prominent nucleus
      3. 
         

         Organelle	Name	Function
         N	Nucleus/Nucleolus	-Contains genetic material/chromatin -Control all cell activities -Secretion of ribososomes
         Q	Mitochondrion

   2. Numerous to provide more energy for propulsion of the sperm towards the ovum/egg.