Biology Paper 3 Questions, Answers and Confidential - Form 4 Term 2 Opener Exams 2023

QUESTIONS

1. You are provided with specimen S. study the specimen carefully then answer questions that follow.
   1. Make a drawing of specimen S and label midrib, leaf lamina. Leaf margin, and leaf petiole.  (3mks)
   2. Name the class to which the specimen belongs.  (1mk)
   3. Identify two features of the specimen S that may have been used to place it in the class named in (b) above.  (2mks)
   4. Using observable features only, explain how the specimen S is adapted to its photosynthetic function.  (6mks)
2.                          
   1.                      
      1. Identify the type of cell division represented in the photographs A and B.  (2mks)
      2. With a reason, name the stage of cell division represented in each case.  (4mks)
      3. Name the part of human body where the process B represented above occurs.  (2mks)
   2.                      
      1. What type of fruit is represented by photograph I? Give two reasons.  (3mks)
      2. Name the agent of dispersal for fruits II and III.  (2mks)
      3. How are the fruits adapted for the mode of dispersal state in (b) (ii) above?  (2mks)
      4. Identify the types of placentation shown by photograph I.  (1mk)
3. You are provided with a sample of food labeled X. Solution Y (Benedict’s solution, solution J (DCPIP), solution L (1%copperII sulphate) Solution N (sodium hydroxide.
   Carry out tests on food sample to indentify the type of food substances present. Record your work in the table below 
   

   Food Test	Procedure	Observation	Conclusion

MARKING SCHEME

1. You are provided with specimen S. Study the specimen carefully then answer questions that follow.
   1. Make a drawing of specimen S and label midrib, leaf lamina, leaf margin, and leaf petiole. (3mk)
      
      D = 1mk
      L=4=2mks
   2.  Name the class to which the specimen belongs. (1mk)
      • Dicotyledonae;
   3. Identify two features of the specimen S that may have been used to place it in the class named in (b) above.
      • Broad lamina; Network/reticulate venation; Presence of a petiole;
   4. Using observable features only, explain how the specimen S is adapted to its photosynthetic function.
      • Numerous leaf veins; to transport water and mineral salts to the photosynthetic cells/remove products of photosynthesis;
      • Green in colour due to the presence of chlorophyll; to absorb light energy for photolysis/ splitting water molecule into hydrogen atom/ion and oxygen atom;
      • Broad lamina; to provide large surface area for absorption of light energy and carbon IV oxide; -Thin leaf to reduce distance for light and gases to/from photosynthetic cells;

CONFIDENTIAL