Biology Paper 3 Questions and Answers - Kakamega Evaluation Mock Exams 2022

QUESTIONS

1.        
   1. You are provided with solutions labelled Q and R, a substance labelled D and a delivery tube fitted with a rubber bung/cork.
      1. Label solution Q as lime water.
      2. Label solution R as 10% sugar solution.
      3. Add substance D to the 10% sugar solution.
      4. Tightly close/plug the boiling tube with the rubber bung/cork fitted with a delivery tube.
      5. Dip the other end of the delivery tube in the test tube containing lime water.
      6. Put the boiling tube in the warm water bath at 40ºC and allow the set up to stand as shown in the diagram below.
      7. Observe the set up for about 15 minutes.
         
         
         1. State the observations made in the lime water. (2mks)
         2. Explain the observations made in the lime water. (2mks)
         3. Name the physiological process that was being investigated. (1mk)
         4. Write a word equation for the physiological process investigated. (1mk)
         5. Why was the warm water bath used in the experiment? (2mks)
   2. Put a drop of the contents in the boiling tube on a microscope slide. Stain with a drop of methylene blue and cover with a cover slip. Observe it under a light microscope using low, medium and high power objective lences.
      1. Draw and label one of the structures observed under the high power objective lens. (3mks)
      2. State the magnification of your drawing. (1mk)
      3. State the identity of substance D. (1mk)
2. The photograph below is of a mammalian heart that has been cut open to expose the inner parts. Study it and answer the questions that follow.
   
   
   1. Name the parts labelled D and E. (2mks)
   2. State the role of part D. (1mk)
   3. Account for the structural differences between the parts marked C and E. (3mks)
   4. State the function of;
      1. Valve A (1mk)
      2. Part B (1mk)
   5.    
      1. Name the part marked G. (1mk)
      2. Account for the structural differences between the parts marked G and E. (3mks)
   6.      
      1. Name the blood vessel marked M. (1mk)
      2. State two defects of the circulatory system. (2mks)
3. You are provided with specimens labelled E and F.
   1.      
      1. Name the sub-division to which the specimens belong. (1mk)
      2. Using observable features on the specimens, give two reasons for your answer in in (a) (i) above. (2mks)
   2. State the differences between the;
      1. Leaves of specimens E and F. (5mks)
      2. Stems of specimens E and F (2mks)
   3. Using observable features on the specimen, state the adaptation of the stem of specimen E to its habitat. (2mks)

CONFIDENTIAL
Each student will require 

1. Lime water-20ml ( solution Q)
2. 10%sugar solution -20ml (solution R)
3. substance D-(Active dry yeast)
4. Boiling tube with the rubber bung /cork fitted with a delivery tube
5. Water bath maintained  at 40°C 
6. Means of timing 
7. A twig of lantana Camara (freshly picked)
8. A twig of wandering Jew (purple/freshly picked) Tradescantia can also do; The twigs should have at least a flower/ fruit.
9. Microscope 
10. Microscope slide 
11. Cover slips 
12. Droppers
13. Methylene blue solution,          

MARKING SCHEME

1.    
   1.      
      1. Bubbles;/Gas formed/Effervescence/seen rej foam or froth line water turns white/milky/cloudy/turbid/white precipitate/white suspension acc.ppt for precipitate.acc white solution/suspension/ppt.tied white ppt alone here can score 2marks in part (ii):Bubbles can only score 1mark in (ii) CO₂ must be mentioned if the reaction made is to be given at(ii)
      2. Gas produced is carbon IV oxide/CO₂;  which forms a (white precipitate)/insoluble salt/insoluble compound/insoluble solid);
      3. N/Proceed to mark at ii) if the observation made is bubbles of gas formed goes ahead to identify the gas; If the observation on lime water is correct i.e insoluble salt/solid/cpd/white ppt,the candidate must mention reacting/dissolving in lime water at(ii)
      4. Respiration/Aerobic respiration/Anaerobic respiration/Fermentation
      5. Anaerobic respiration: Glucose (sugar) +Oxygen D/Yeast/Enzyme/zymese enzyme carbon IV oxide/carbon dioxide + water + energy (ATP)
         Anaerobic respiration: Glucose (sugar) D/Yeast/Enzyme/zymase Ethamol/Alcohol/Ethyl alcohol + carbondioxide + Energy/ATP
      6. To provide optimum temperature/most suitable/favourable/best for enzyme activity/action/working/functioning/reaction e.g to activate the enzymes
   2.    
      1. 
         
         rej if what is drawn is a plant cell, field of view..WD if WD no mark for L
         Reject D if more than I cell drawn
         Reject D if no nucleus drawn
         D mark:
         Double continuous line: No compass /coin/wavy/dotted
         Ignore cytoplasmic inclusions
         Nucleus can/cannot be shaded
         Award if drawn with a bud
         Label mark
         Label must touch the structure
         Spellings must be
         No arrows/crossing of label lines
      2. If formula is given, it must be correct i.e eye piece x objective
         Consider working x 200   ____ 675
          (x5, x10x15)      (x40,x45      5x40 -200    5x45 -225
         X3x4x7                  x50,x60x65  15x40-600  15x45-675  
      3. yeast/Yeast cell/Yeast cell/ganules/bud/budding/substance
         yeast parent cell/powder fungus
         x3x40 =120         x4x40 =160
         x3x45 =135         x4x45 =180
         x3x50 =150         x4x50 =200
         x3x60 =180         x4x60 =240
         x3x65 = 195        x4x65 =260
2.      
   1. D: Septum (ventricular ) ;
      E: Ventricle (ventricular wall) ;
   2. To prevent mixing of oxygenated blood (on the left side of the heart) with the deoxygenated blood (on the right side)
   3. C has thinner walls to pump blood to the lungs (alone/only).
      E has thicker more muscular walls to pump blood to all parts of the body.
   4.        
      1. To prevent back flow of blood from the ventricles to the auricles
      2. To prevent the valves from turning inside out
   5.         
      1. a trium/auricle
      2. G-auricle is smaller in volume; to temporarily hold the blood and pass it to the ventricles (E) which have a larger volume to pass the blood to the lungs and all other body parts
   6.      
      1. Aorta (rej wrong spelling)
      2. Thrombosis; Varicose veins;Arteriosclerosis
         Hypertension/High blood pressure  (mark the first 2)
3.      
   1.      
      1. Angiospermaphyta/Angiospermae/Angiospermatophyta
      2. Presence of fruits/presence of flowers; seeds enclosed in fruit; Ovules in flowers; presence of veins (in leaves);
   2.      
      1.    
         

         LEAF E	LEAF F
         1. Broad  2. Opposite  3. Net veined  4. Serrated margin/saw like margin  5. Not/Non succulent  6. Rough surface  7. Has (compact) petiole/leaf stalk  8. Green  9. Thin  10. Ovate	Narrow Alternate Paralled veined Smooth/entire margin Succulent/fleshy Smooth surface Has sheath/sheath-like petiole Purple Thick Lanceolate

      2.  
         

         STEM E	STEM F
         1. Angular/Rectangular/Four sided/square cuboid 2. Pricky/Thony/spiny/prickly/spiky  3. Woody/Hard  4. Green/Grey  5. No succulent  6. Leaves opposite	Round/Cylindrical/circular Smooth/Hairy Herbaceous/soft Purple Succulent/fleshy/juicy Leaves alternate

   3. Spiny/thorny/pricky/prickly for protection against browsers/Herbivores/Animals woody/Hard for mechanical support