Biology Paper 3 Questions and Answers - Arise and Shine Pre Mock Exams 2023

Instructions to the Candidates.

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

For Examiner’s Use Only

QUESTIONS

1. You are provided with specimen K. Use it to answer the questions that follow.
   1. Cut a traverse section of specimen K and draw a well labeled diagram of the cut surface. (4 marks)
   2. State the type of placentation of specimen K (1 mark)
   3. Apart from the placentation named in (ii), name two other form of placentation. (2 marks)
   4. Squeeze out the juice from one of the halves of the specimen K and put it in a beaker. Using the reagents provided, carry out test to identify the food substances present in the juice. (7 marks)
      

      Food substance	Procedure	Observation	Conclusion

2. The diagram represents organisms in a certain habitat.
   
   
   1. State two observable characteristics of living things displayed by the organisms. (2 marks)
   2.                    
      1. Name the respiratory surface used by the organism. (1 mark)
      2. State three adaptations of the respiratory surface named in (b) (i) above. (3 marks)
   3. The organism is found in Kingdom Animalia. Giving two external features, identify the phylum to which it belong.
      Phylum (1 mark)
      External features (2 marks)
   4. By use of arrows, show the life cycle of this organism. (1 mark)
   5. Complete the table shown below on the hormones, site of production and the functions played by these hormones in metamorphosis. (3 marks)
      Name of Hormone                 Site of Production              Function of the Hormone
      .....................................          Corpus allatum                     Formation of larval cuticle
      Ecdysone                             .....................................          .....................................
3. You are provided with the following:
   • specimen Y
   • Hydrogen peroxide
   • 2 test tubes in a test tube rack.
   • 2 labels
   • 10ml measuring cylinder.
   • A scalpel.
   • 2 wooden splints.
   • 100ml beaker.
     Procedure
     1. Label two test tubes A and B.
     2. Measure 2cm₃ of hydrogen peroxide and put in test tube A. Repeat the same procedure for test tube B.
     3. Cut a small piece of specimen Y to two smaller pieces using a scalpel. Place one of the pieces in test tube A and retain the other piece for the subsequent procedure for test tube B.
     4. Immediately, introduce a glowing splint into the mouth of the test tube. Record your observations in the table below.
     5. Put the other piece of specimen Y in an empty 100ml beaker then add 50ml boiling water from a hot water bath maintained at 80ºC. Leave the set up for 5 minutes
     6. Remove specimen Y from the boiling water using a pair of forceps and place in test tube B. Immediately, introduce a glowing splint at the mouth of the test tube. Record your observations in the table below.
        1. Record your observations in this table (5 marks)
           

           Test tube	Observations
           	On placing specimen Y	On introducing a glowing splint
           A	(i)       (ii)
           B

        2. Explain your answers in (a) above.
           1. A (3 marks)
           2. B (1 mark)
        3. State the role of experimental set up in test tube B. (1 mark)
        4. Specimen Y is an organ in animals. Name the organ and state two other functions apart from detoxification.
           Name of organ (1 mark)
           Functions (2 marks)

MARKING SCHEME

1.                
   1.                
      1.               
         • Conditions for a biological drawing
           • • Continuous outline D1
             • No shading 1 mark
             • Transverse section – D2 1 mark
         • Labels
           • Labeling line must touch intended structure
           • Labeling line must be continuous
           • No arrowheads
           • No criss-crossing
           • Label must be singular if 1 labeling line touches 1 structure
           • Any 2 correct labels
      2. Axile (placentation); (1 mark)
         Parietal;
         Marginal;
         Basal;
         Free central; Mark 1st 2 correctly spelled placentation
      3. 
         

         Food substance	Procedure	Observation	Conclusion
         Protein(s)	To (2ml of) food substance, add (equal amount of) sodium hydroxide solution then add copper (II) sulphate solution dropwise;             (1 mark)	Blue colour (of copper (II) sulphate solution) retained;         (1 mark)	Protein(s) absent; (1 mark)
         Non-reducing sugar(s)	To (2ml of) food substance, add (2 drops of) hydrochloric acid, heat, cool; add sodium hydrogen carbonate solution dropwise until fizzing stop.  Add (equal amount of) Benedict’s solution then heat/boil/warm/place in hot waterbath; (2 marks)	Green colour observed; Yellow/orange/brown; (1 mark)	Non-reducing sugar(s) present; (1 mark)

         Distribution of marks:
         • Food substance column – see correct food substance but do not award marks.
         • Procedure – use correct chemical symbols of reagent if words are not used.
         • Observation – reject alternative colours.
         • Conclusion – correctly spelled food substance and traces of for green colour in non-reducing sugar.
   2. Growth and development;
      Reproduction;
      Nutrition; Mark 1st 2

b)

1. tracheole; Reject wrong spelling but underline plural to allow to mark (ii)
2. Ramify body tissues for direct supply to individual cells; thin to reduce diffusion distance; moist walls to dissolve gases (into solution form); lack chitin to permit gaseous exchance;
   • Tied to 2(b) (i)
   • Mark 1st 3

c). Phylum: Arthropoda; Reject wrong spelling
External feature:

• Segmented bodies;
• Jointed appendages;
• Exoskeleton;
  External features tied to phylum, marks 1st 2

(d) Egg(s) → Nymph(s)  → Adult(s);
Award correct arrows on the diagram.

(e)

 3.
(iii) (a) (5 marks)

(b) Tied to (a)

1. Catalase (enzyme); breakdown hydrogen peroxide; into water and oxygen; (3 marks)
2. Boiling denature catase enzyme; (therefore breakdown of hydrogen peroxide hence no oxygen formed) (1 mark)

(c) Control experiment; reject acts as a control experiment.

(d) Name of organ: Liver;
Functions:

• Blood sugar regulation;
• Deamination;
• Thermoregulation;
• Haemoglobin regulation;
• Regulation of plasma proteins;
• Manufacture of red blood cells during foetus stage;
• Formation and elimination of excess cholesterol;
• Storage of blood;
• Storage of vitamins B, C, E, K and mineral; Mark 1st 2

CONFIDENTIAL

Each Candidate Requires The Following:

1. About 5g(small)piece of specimen Y.
2. 4 test tubes in a test tube rack and 2 droppers.
3. 10ml of 20% hydrogen peroxide solution in a test tube.
4. 100ml empty beaker – 2.
5. 10ml measuring cylinder.
6. A pair of forceps.
7. Access to hot water maintained at 80°C from a hot water bath.
8. 2 wooden splints.
9. (1 ripe orange fruit labeled specimen K).
10. Scalpel.
11. Access to:
    1. Sodium hydroxide solution - 4ml per candidate.
    2. Copper (II) sulphate solution - 2ml per candidate.
    3. Dilute hydrochloric acid - 2ml per candidate.
    4. Sodium hydrogen carbonate solution - 2ml per candidate.
    5. Benedict's solution - 4ml per candidate.
    6. Source of heat.

Note:

• 5g (small) piece of fresh liver labeled as specimen Y.
• 1 ripe orange fruit labeled specimen K.