Biology Paper 3 Questions, Answers and Confidential - Kassu Jet Pre Mocks 2022

INSTRUCTIONS TO CANDIDATES

• Answer all the questions in the spaces provided
• You are required to spend the first 15 minutes of 1 ¾ hours allowed for this paper reading the whole paper carefully before commencing your work
• Candidates may be penalized for recording irrelevant information and for incorrect spelling especially of technical terms 

FOR EXAMINER’S USE ONLY

QUESTIONS 

1. You are provided with a nutritional supplement labelled S, distilled water and a boiling tube Put about 6ml of the distilled water in the boiling tube and add the nutritional tablet to dissolve it Use the reagents provided to find out the food substances present in the tablet (12 mks)
   

   Food substance	Procedure	Observation	Conclusion

2.                        
   1.                        
      1. You are provided with a pestle, mortar, scapel, specimen Q and R Cut from each a cube, each measuring 1cm by 1cm put them each in a different test tube having 10mls of solution X Record the observations in the table below? (2 marks)
         

         Specimen	Observation
         Specimen Q
         Specimen R

      2. Account for the observations in the experiment involving specimen Q and R? (2 marks)
   2.                          
      1. Using the remaining portion of specimen Q, Cut 2 other pieces measuring 1cm by 1cm ,Crush them separately to form a paste and put them in boiling tubes labelled A and B
         To the paste in boiling tube labelled A, add 5mls of solution X Record the observation in the table below
          To the paste in boiling tube labeled B add 10mls of distilled water and boil for 5 minutes then allow it cool then add 5mls of solution X Record the observation in the table below (2 marks)
         

         BOILING TUBE	OBSERVATION
         A
         B

      2. Account for the observations in the experiment involving boiling tube A and B (4 marks)
         Boiling tube A
         Boiling tube B
      3. Name the biological substance being investigated and its significance to the living tissues (2 marks)
         Biological substance
         Significance
      4. Name the factor being investigated in question 2(b) above (1mark)
3. The diagrams below show a method of reproduction
   
   
   1. Name the mode of reproduction above and give an example of organism where it occurs (2mks)
   2. Briefly explain how the process occurs (4mks)
   3. Study the following photograph and answer the questions that follow
   4. Describe the features of the above photograph with respect to the following (3mks)
      1. Androecium
      2. Gynoecium (3mks)
   5.                        
      1. Suggest the agent of pollination of the flower (1mk)
      2. Explain how it is adapted to pollination agent you have named in (b)(i)above (2mks)

MARKING SCHEME

1. You are provided with a tablet which is a nutritional supplement, distilled water and a boiling tube. Put about 6ml of the distilled water in the boiling tube and add the nutritional tablet to dissolve it to form solution T. Use the reagents provided to find out the food substances present in the tablet.
   

   Food substance	Procedure	Observation	Conclusion
   Ascorbic acid/Vitamin C	Put DCPIP into the test tube. Add solution T dropwise to the DCPIP	DCPIPis decolourised	Vitamin C/Ascorbic acid present
   Starch	To solution T in a test tube, add iodine solution	Brown colour of iodine persists;	Starch absent
   Reducing sugars	To solution T in a test tube, add an equal amount of Benedict’s solution, shake the mixture and boil/ heat to boil in a water bath.	Colour changed from blue,green,yellow,orange	Reducing sugars present
   Proteins	To solution T in a test tube, add an equal amount of sodium hydroxide. Add copper(II) sulphate dropwise and shake mixture	Blue colour of copper (II) Sulphate persists	Proteins absents

2.                                        
   1.                              
      1. You are provided with a pestle, mortar, scapel specimen Q and R,. Cut from each a cube, each measuring 1cm by 1cm. put them each in a different test tube having 10mls of solution X. Record the observations in the table below? (2marks)
         

         Specimen	Observation
         Specimen Q	A lot of bubbling / Effervescence / Fizzling
         Specimen R	Little bubbling / less effervescence / little fizzling

      2. Account for the observations in the experiment involving specimen Q and R? (3marks)
         • There is more bubbling / more gas produced in Q (liver) than in R banana; since there is more metabolic activities in Q than in R; Animals are more active than plants;
   2.                            
      1. Using the remaining portion of specimen Q. Cut 2 other pieces measuring 1cm by 1cm ,Crush them separately to form a paste and put them in boiling tubes labeled A and B.
         To the paste in boiling tube labeled A, add 5mls of solution X .Record the observation in the table below.
         To the paste in boiling tube labeled B add 10mls of distilled water and boil for 5minutes then allow it cool then add 5mls of solution X. Record the observation in the table below? (2marks)
         

         BOILING TUBE	Observation
         A	fast/rapid/More effervescence/fizzing /bubbling
         B	Fewer/no/very little effervescence/fizzing /bubbling

      2. Account for the observations in the experiment involving boiling tube A and B? (4marks)
         • Boiling tube A
           Crushing increases surface area for enzyme catalase; rapid / faster metabolism / breakdown of hydrogen peroxide occurs
         • Boiling tube B
           Boiling denatures the cells / enzyme catalase; reduces enzyme activity / metabolism / substrate breakdown.
      3. Name the biological substance being investigated and its significance to the living tissue? (2marks)
         • Biological substance
           Catalase/enzyme
         • Significance
           Detoxification/breakdown harmful substance/hydrogen peroxide
      4. Name the factor being investigated in question 2(b) above (1mark)
         • Effect of temperature on enzyme action
3.                                    
   1. Study the following photograph and answer the questions that follow
      1. Name the mode of reproduction above and give an example of organism where it occurs.2mks
         • Budding; in yeast,
      2. Briefly explain how the process occurs? 4mks
         • cytoplasm bulges out forming bud;which enlarges until almost equal in size to mother cell;nuclear division occurs and a cross wall is formed between the two cells;which then separate;
      3. Describe the features of the above photograph with respect to the following (3mks)
         1. Androecium
            • Has five stamens
            • Has short slender filaments each arising from the base of the ovary
            • Anthers are large and yellow
            • Anthers are below the stigma and surrounding the style
         2. Gynoecium (3mks)
            • style longer than the filament/stigma above anthers
            • Single superior ovary
            • Has one long hairy style
      4.                                
         1. Suggest the agent of pollination of the flower (1mk)
            • Insect (rej animal )
         2. Explain how it is adapted to pollination agent you have named in (b)(i)above (2mks)
            • Has coloured petals to attract insects
            • Large/conspicuous petals to attract insects

Confidential

All candidates to be supplied with:

1. Pestle and mortar
2. Specimen Q: LIVER
3. Specimen R : Banana/ raw :3 students can share 1
4. Measuring cylinder
5. Ruler
6. 20ml Hydrogen peroxide (solution X)
7. Source of heat
8. 2 Boiling tubes
9. 4 test tubes
10. Distilled water
11. Labels
12. Stop watch