Biology P3 Questions and Answers with Confidential- Form 3 Term 3 Opener Exams 2022

Instruction to Candidates

• Write your Name, Adm. No., Class and Date in the spaces provided
• Answer all the questions
• You are required to spend the first 15 minutes of the 13/4Hrs around for this paper reading the whole paper carefully before commencing your work
• Answers must be written in the spaces provided in the question paper. Additional Pages must not be inserted.

QUESTIONS

1. You are provided with visking tubing a solution labelled E, Iodine solution labelled solution F. Benedict’s solution labelled solution L, and a piece of thread.
   Tie one end of the visking tubing tightly using the thread provided. With the help of a dropper put 10ml of the solution labelled E into the visking tubing. Tie the other end of the visking tubing tightly.
   Ensure that there is no leakage at both ends of the visking tubing. Wash the outside of the visking tubing with water. Place the visking tubing in a 100ml beaker. Add distilled water into the beaker to reach the level of the liquid in the visking tubing. Allow the setup to stand for 30 minutes or more.
   1. Using 2ml in a test tube in each case test for the food substance in the liquid outside the visking tube using. (3mks)
      

      TEST	PROCEDURE	OBSERVATION	CONCLUSION
      Iodine Solution(Solution F)
      Benedict’s solution (Solution L)

   2. Using 2ml in a test tube in each case test for the food substance in the contents of the visking tubing using. (3mks)
      

      TEST	PROCEDURE	OBSERVATION	CONCLUSION
      Iodine Solution(Solution E)
      Benedict’s solution (Solution L)

   3. Account for your results in a and b above. (4mks)
   4. Highlight the role of the physiological process demonstrated here (1mk)
2. The photograph below is of a mammalian heart. Study it and answer the questions that follows
   
   
   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. Name:
      1. Valve A (1mk)
      2. State it’s function. (1mk)
   5. Name the part marked C. (1mk)
   6.                    
      1. Name the blood vessel marked H. (1mk)
      2. State two fuctional differences between the arteries and the veins. (2mks)
   7. State 3 structural adaptations of the heart (3mks)
3. Study the following illustration of various mammalian teeth and answer the questions that follow.
   
   
   1. Identify the teeth. (4mks)
      A.................................
      B.................................
      C.................................
      D.................................
   2. Complete the table below. (8mks)
      

      Tooth	Function	Adaptation
      A
      B
      C
      D

   3. Write the dental formula of an adult human being. (1mk)
   4. Distinguish between heterodont and homodont animals. (1mk)

MARKING SCHEME

1. You are provided with visking tubing a solution labelled E, Iodine solution labelled solution F. Benedict’s solution labelled solution L, and a piece of thread.
   Tie one end of the visking tubing tightly using the thread provided. With the help of a dropper put 10ml of the solution labelled E into the visking tubing. Tie the other end of the visking tubing tightly.
   Ensure that there is no leakage at both ends of the visking tubing. Wash the outside of the visking tubing with water. Place the visking tubing in a 100ml beaker. Add distilled water into the beaker to reach the level of the liquid in the visking tubing. Allow the setup to stand for 30 minutes or more.
   1. Using 2ml in a test tube in each case test for the food substance in the liquid outside the visking tube using. (6mks)
      

      TEST	PROCEDURE	OBSERVATION	CONCLUSION
      Iodine solution (Solution  f)	To 1cm3of solution add 2 drops of iodine solution.	The colour of iodine remains	Starch absent
      Benedicts  solution (Solution L)	To 2cm3 of solution add an equal amounts of Benedicts solution and gently heat	Colour of Benedicts solution changes from blue – green- yellow – brown-red	Reducing Sugar present

   2. Using 2ml in a test tube in each case test for the food substance in the contents of the visking tubing using. (3mks)
      

      TEST	PROCEDURE	OBSERVATION	CONCLUSION
      Iodine solution solution (f)	To 1cm3 of solution add  2 drops of iodine solution	The colour of iodine changes to blue- black	Starch present.
      Benedict’s solution (Solution  L)	To 2cm3 of solution add an equal amounts of Benedict’s solution and gently heat	Colour of Benedicts solution changes from blue-yellow-orange	Reducing Sugar present.

      ½ mrk for each correct answer.
   3. Account for your results in a and b above. (4mks)
      • glucose diffused across the visking tubule since it is smaller in size; compared to the starch. Hence the test for reducing sugars was positive
   4. Highlight the role of the physiological process demonstrated here (1mk)
      • Absorption of mineral salts from the soil by the plants/digested food/gaseous exchange in plants and animals/removal of nitrogenous wastes/Translocation of food in the plants.
2. The photograph below is of mammalian heart. Study it and answer questions that follows
   1. Name the parts labelled D and E. (2mks)
      • D longitudinal septum; septum;
      • E Left ventricle
   2. State the role of part D. (1mk)
      • Separates the left side from the right side of the heart hence preventing mixing of oxygenated and deoxygenated blood.
   3. Account for the structural differences between the parts marked C and E. (3mks)
      • E is more muscular than C;E pumps blood to the rest of the body which is a longer distance while C pumps blood to the ventricle which is a shorter distance.
   4. State the function of
      1. Valve A-Tricuspid
      2. Prevent back flow of blood when the ventricles contract. (1mk)
   5. Name the part marked C. (1mk)
      • Left Auricle/atriaum
   6.                
      1. Name the blood vessel marked H. (1mk)
         • Aorta
      2. State two fuctional differences between the arteries and the veins (2mks)
         

         arteries	veins
         Carry blood away from the heart	Carry blood toward the heart
         Blood under high pressure	Blood under low pressure
         Carry oxygenated blood except pulmonary artery	Carry deoxygenated blood except pulmonary vein

   7. State 3 structural adaptations of the heart (3mks)
      

      Cardiac muscles which are myogenic

      Septum prevent mixing of oxygenated and deoxygenated blood

      Coronary artery which provide nutrients and oxygenated blood to heart muscles

      Coronary vein carry nitrogeneous waste and deoxygenated blood to heart muscles

      Left ventricle thicker than right ventricle as it pump blood to all body parts

3. Study the following illustration of various mammalian teeth and answer the questions that follow.
   1. Identify the teeth. (4mks)
      • A Premolar B Molar C Incisor D Canine
   2. Complete the table below. (8mks)
      

      Tooth	Function	Adaptation
      A	Crushing and grinding food	Has, ridges and cusps large surface area for grinding
      B	Crushing and grinding.	Has ridges and cusps Has three roots for firm anchorage Classified to provide hard grinding surface.
      C	Cutting and biting food/laterally flattened	Chisel shaped for cutting One root for firmly attachment into the jaw
      D	Seizing prey and reaping off fresh	Conical shaped/pointed tip for seizing prey and reaping off fresh one root for anchorage into the  jaw

   3. Write the dental formula of an adult human being. (1mk)
      • ²/₂ c ¹/₁ pm ²/₂ m ³/₃ = 32
   4. Distinguish between heterodont and homodont animals. (1mk)
      • Heteredont are animals with differentiated teeth (Incisor, Canines premolar and molars, while homodont are animals with teeth that are similar.

COFIDENTIAL

1. 10m/s of solution E ( a mixture of starch and glucose in ration 1:2.
2. Iodine solution labelled solution F.
3. Benedict’s solution labelled solution L.
4. Four test tubes in a test tube rack
5. Droppers (2)
6. Source of heat
7. 10ml measuring cylinder
8. Visking tubing (8cm)
9. Two pieces of thread (10cm)
10. 100ml beaker
11. Wash bottle with distilled water
12. Means of timing
13. Test tube holder.