Biology Paper 3 Questions and Answers with Confidential - Lainaku II Joint Mock Examination 2023

INSTRUCTIONS TO CANDIDATES:

• Answer all the questions 
• You are required to spend the first 15 minutes of the 1 ¾ hours allowed for this paper, reading the whole paper carefully before starting to do this paper.

1. You are provided with two test-tubes. Label them as A and B. You are required to prepare the contents of test tube A and B as follows. To test tube A, add 2cm³ of solution R provided and test using the provided reagent. To test tube B, add 2cm³ of solution T provided and test using the provided reagent.  (5 Marks)
   1.  
      

      Test tube	Procedure	Observation	Conclusion
      A
      B

   2. To the provided visking tubing tie one end with the provided string and add solution R. Tie the remaining end and immerse it in a solution of iodine solution in a beaker (50ml). After 5-10 minutes remove it from the beaker and observe.
      1. What was your observation of the contents of the visking tubing at the end of experiment? (1 Mark)
      2. Account for your results in (i) above. (4 Marks)
   3. Explain two roles of physiological process under investigation in (c) above in living organisms.  (2 Marks)
   4. You are provided with specimen Q. Cut a longitudinal section specimen of specimen Q to make two parts. Add one drop of iodine solution on the surface of one of the exposed surfaces.
      1. State the observation (1 Mark)
      2. Explain the observations made in d(i) above. (3 Marks)
2. The photographs below shows different types of flowers. Photograph V is a flower obtained from a Hibiscus plant while photograph W is a flower obtained from Bougainvillea plant.
   
   1. On the photograph, name the part labelled J and K (2 Mark)
   2.  
      1. Name the agent of pollination for the flowers in the photograph (1 Mark)
      2. State three observations on the photographs that support the answer you have given in (b)(i) above  (3 Marks)
   3.  
      1. Name the class of plant from which the photograph V was taken (1 Mark)
      2. Using observable features on the photograph, give the three reasons for your answer in c (i) above (3 Marks)
      3. Name part labelled E on the photograph W (1 Marks)
3. The photographs below were taken from specimens obtained from mammalian skeleton. Evaluate them and use them for answering questions.
                  
   1. Identify the bone labelled X, Y, and T (3 Marks)
      X
      Y
      T
   2. State the function of part labelled M in bone P (1 Mark)
   3.    
      1. Name the type of joint formed in the proximal end of bone T (1 Mark)
      2. State two characteristics of the joint named in c(i) above (2 Marks)
      3. On the image U, label two parts. (2 Marks)
   4. Discuss various adaptations of bone W to its functions (4 Marks)

CONFIDENTIAL

INSTRUCTIONS TO SCHOOLS

Each student should be provided with the following:

Question 1

1. 4 test tubes per rack
2. Solution R – 1% starch solution
3. Solution T – Distilled water
4. Two labels
5. 15 cm string (2 strings)
6. 10 cm long visking tubing
7. Iodine solution
8. 50 ml beaker
9. Specimen Q-Dry maize seed/fruit/grain.
10. Scalpel
11. Pair of forceps (or access to)
    NOTE; ALL PHOTOGRAPHS IN PP1 AND PP3 MUST BE COLOURED

MARKING SCHEME

1.  
   1.  
      

      Test tube	Procedure	Observation	Conclusion
      A	Put 2cm3 of R in a test tube and 2   drops   of   iodine solution/Put R in   a test tube   and   add   iodine   solution;	Blue-black;	Starch   present;
      B	Put 2cm3of Rin a test tube and 2   drops   of   iodine solution/Put R in   a test tube and  add iodine solution	Yellow/brown;	Starch   absent;

                                                                                                                                    (5 Marks)
      (In B only observation and conclusion attract 1 mark each). No marks for procedure but must be correct if the student is to earn marks for observation and conclusion
   2.  
      1. Liquid R/ Contents inside the visking tubing turns blue-black; (1 Mark)
      2. Iodine molecules are (relatively) small; they diffused; into the visking tubing reacting with R/the contents to give blue-black colouration; shows presence of starch in R; (4 Marks)
   3.  
      • Absorption/taking up of mineral salts by root hair from the soil solution into the plant;
      • Absorption of digested food across the wall of the ileum into the blood stream;
      • Carbon IV oxide and oxygen move by diffusion/this process across respiratory services in living organisms;
      • Waste substances like nitrogenous waste are removed from organisms like unicellular organisms by diffusion;
        (2 Marks) (Any 2 correct)
   4.  
      1. Endosperm turns blue-black in colour/changes colour to blue black; (reject if endosperm is not mentioned) (1 Mark)
      2. Endosperm contains starch; that has been stored. Starch in the endosperm reacted/mixed with iodine solution to form a blue black substance; Embryo and scutellum do not contain starch; (3 Marks)
2.  
   1. J-Staminal tube; K- Stigma;(2 Mark) must be labelled on the photograph
   2.  
      1. Insect; (accept when specific insect is named) reject-insect pollination (1 marks)
      2.  
         • Brightly coloured/conspicuous bracts/petals/sepals/flower;
         • Landing stage/platform;
         • Tabular Corolla/stamen (filament and anther) and pistil enclosed; (3 marks)
   3.  
      1. Dicotyledonae; reject dicot/dicotyledon/wrong spelling/if D is small letter (1 Mark)
      2.  
         • Five petals/five petals/floral parts occur in 5’s;
         • Broad lamina/leaf lamina;
         • Network veins/venation/reticulate venation; (3 Marks)
      3. Bract; (1mk)
3.  
   1. X-Lumbar vertebra; Y-Thoracic vertebra; Z-Humerus; (3 Marks)
   2. Passage of vertebral artery; (1 Mark)
   3.  
      1. Ball and socket joint; (1 Mark)
      2.  
         • Movement is possible in all directions/planes;
         • Enable rotation through 360 degrees/rotate through 360 degrees; (2 Marks)
      3. Spine; Glenoid cavity; supra scapula; (2 Marks)
   4.  
      • Prominent head of femur fits into the acetabulum forming the hip joint; that enable movement
      • Greater and lesser trochanter form large/long extension for attachment of thigh muscle
      • Expanded and rounded knobs called condyles/ lateral and medial condyles that articulate with patella (knee cap) and tibia with a hinge joint;
      • Hard/ossified shaft to support/bear the weight of the body;
      • Long/large shaft to increase surface area for attachment of thigh muscle; (any correct 4) (4 Marks)