Biology Paper 3 Questions and Answers - Baringo North Joint Evaluation Mock Exams 2022

Questions

INSTRUCTIONS TO CANDIDATES

• Answer all the questions in the spaces provided.
• You are required to spend the first 15 minutes of the 1 ¾ hours allowed for this paper reading the whole paper carefully before commencing your work.

1. You are provided with specimen P and Q. Examine them carefully and answer the questions that follow.
   1. State three observable differences between P and Q. (3mks)
      

      Specimen P	Specimen Q

   2. Identify the parts of the flower from which specimen P and Q developed. (2mks)
      P 
      Q 
   3.      
      1. Make a longitudinal section of specimen P. Draw a well-labelled diagram of one half with all its Contents intact. (4mks)
      2. State the functions of any two structures in (c) (i) above. (2mks)
   4. Using a mortar and pestle crush specimen Q, add 5ml distilled water to make a solution Q and carry out appropriate tests using the reagents provided. (6mks)
      

      Test	Procedure	Observation	Conclusion

2.  Study the photos below.
   
   
   1. Name:-
      1. The stimulus operating in Plant K1. (1mk)
      2. The type of response being investigated in Plant K2. (1mk)
      3. Suggest a control set up for Plant K2 investigation. (1mk)
   2. Describe the role of auxins in the response exhibited by Plant K1. (4mks)
   3. What is the biological value of the tropisms evident in: -
      1. Plant K1 (1mk)
      2. Plant K2 (1mk)
3. Below are photos of of a certain arthropod at different stages of its life cycle.
   
   
   1. Identify the stage of the life cycle represented by organism S. (1mk)
   2.     
      1. Name the stage that immediately preceed and succeed organism S in the life cycle. (2mks)
         Preceeding stage
         Succeeding stage.
      2. What name is given to the complete life cycle of the arthropod? (1mk)
   3. Name the gaseous exchange system of orgaism S. Give a visible featuret that supports your answer. (2mks)
   4.  
      1. What type of food does organisms S feed on? Give a reason to support your answer. (2mks)
      2. State the significance of stage U in the life cycle of the beetle. (2mks)
      3. How is specimen T adapted to locomotion in its habitat ? (2mks)
   5. State the role of the following in the life cycle of the arthropods. (2mks)
      1. Juvinile hormone.
      2. Moulting stimulating hormone.

Marking Scheme

1.       
   1.    
      

      Specimen P	Specimen Q
      -Has two scars	-Has one scar
      -Has one cotyledon	-Has two cotyledons
      -Has Food stored in endosperm	-Stores food in cotyledons.

   2. P- Ovary;
      Q- Ovule;
   3.          
        
      1. D-1mk
         L- 1X3= 3mks N/B Mark first 3 labels clockwise.
      2. -Endosperm- Storage of food;
         -Embryo (plumule and radicle)- Develops into shoot and roots;
         -Testa – Protects inner delicate parts/embryo;
         - Coleoptile – Protects plumule from mechanical damage during germination;
   4.       
      

      Test	Procedure	Observation	Conclusion
      Starch	To 2ml solution Q, Add 3drps of Iodine solution;	Blue black colour ;	Starch present;
      Protein	To 2ml solution Q, Add equal amount of sodium hydroxide. Add Copper(II) sulphate drop by drop;	Colour changes to purple/violet/mauve;	Proteins present;

2.          
   1.        
      1. Touch;
      2. Positive phototropism;
      3. Place the potted plant on a revolving klinostat in a similar set up.
   2. When the tendril comes into contact with the upright firm support; auxins migrate to the opposite side/side away from touch;
      This causes faster cell growth/ cell elongation on the side away from the contact/OR causes
      Slower growth on the side in contact with the firm support; and the tendril coils round the support;
   3.      
      1. K1- It offers support to the non-woody stem/plant;
         K2- The plant shoot grows towards the source of light in order to photosynthesize;
3.  
   1. S- Larva;
   2.      
      1. Preceding stage -Larva;
         Succeeding stage- Pupa;
      2. Complete metamorphosis;
   3. – Tracheal system;
      - Presence of spiracles;
   4.      
      1. - Vegetation/ plant material;
         - Has biting mouth parts;
      2. It undergoes re-organization of body tissues to form the adult form (ie metamorphosis);
      3. – Has wings for flight;
         Has jointed legs for walking/crawling;
   5.   
      1. - Stimulates shedding of the larval cuticle while retaining the youthful characteristics/ prevents metamorphosis;
      2. Stimulates shedding of the adult cuticle/moulting in adult;