Biology Questions and Answers - Form 2 Term 2 Opener Exams 2022

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QUESTIONS
Answer all questions in the spaces provided

  1. Distinguish between the following terms: - 4marks
    1. Magnification and resolution of a microscope
    2. Mounting and staining of a specimen
  2. Name the organelle that performs each of the following functions in a cell. 3marks
    1. Transport of packaged glycoproteins
    2. Destruction of worn out cell organelles
    3. Synthesis of proteins
  3. Given that the diameter of the field of view of a light microscope is 2000um. Calculate the size of a cell in mm if 10 cells occupy the diameter of the field of view 2marks
  4. State three physiological processes that are involved in movement of substances a cross the cell membrane 3marks
  5. The diagram below illustrates the behaviour of red blood cells when placed into two different solutions X and Y.
    1
    1. Suggest the nature of solutions X and Y. 2marks
      X
      Y
    2. Name the process A and B.
      A
      B
      2marks
    3. What would happen to normal blood cell if it were placed in an isotonic solution? 2marks
  6. The diagram below represents a cell organelle
    2
    1. Name the part labeled Y 1mark
    2. State the function of the part labeled X 1mark
  7. Briefly explain the fate of the following products from the light stage of the process of
    Photosynthesis: 3 marks
    1. Oxygen atoms
    2. Hydrogen ions
    3. ATP
  8. Name the diseases caused by deficiency of: 2marks
    1. Iodine
    2. Vitamin C
  9.            
    1. What is peristalsis? 1 mark
    2. Explain how the process above is brought about.
      2marks
    3. What are the two functions of bile salts during the process of digestion. 2marks
  10. The table below shows three enzymes A, B and C and their respective optimum PH.
    Enzyme Optimum PA
    A 6.8
    B 2.0
    C 8.0
    1. Name the most likely region of the alimentary canal of a mammal where enzyme
      B would be found. 1 mark
    2. Give a reason for your answer in (a) (i) above 2marks
  11. Study the dental formula given below:
    0/4 C0/0 PM3/3 M2/3
    1. Identify with reasons the mode of feeding of the animals whose dental formula is given above
      Mode 1mark
      Reasons 2marks
    2. Calculate the total number of teeth in the mouth of the above animal. Show your working.
      2marks.
  12.        
    1. Define the term transpiration 2marks
    2. State three types of transpiration 3marks
    3. List three forces that facilitate the transport of water and mineral salts up the stem. 3marks
    4. Name the tissue that is removed when the bark of a dicotyledonous plant is ringed 1 mark
  13. The figure below represents a diagram of a photometer;
    3
    1. What is the potometer used for? 1 mark
    2. Give two precautions, which should be taken when setting up a potometer 2marks
  14. Name the blood vessel that nourishes the heart 1 mark
  15. In which form is oxygen transported in the blood. 1 mark
  16.            
    1. State three structural differences between arteries and veins in mammals. 3marks
    2. Name a disease that causes thickening and hardening of arteries 1 mark
  17. Explain two advantages of closed circulatory system over open circulatory system. (2marks)
  18. List the components of animal circulatory systems 3 marks
  19. Give two structural differences between a red blood cell and a white blood cell. 2 marks.
  20.        
    1. what is blood clotting? 1 mark
    2. Name a protein, vitamin, and an enzyme involved in blood clotting. 3marks
  21.      
    1. What is immunity? 1 mark
    2. Distinguish between natural and acquired immunity 2 marks
  22. What is the role of vaccination against certain diseases 1 mark?

MARKING SCHEME

  1. Distinguish between the following terms: - 4marks
    1. Magnification and resolution of a microscope
      Magnification. Ability of a microscope to enlarge tiny objects
      Resolution. Ability of a microscope to separate between two tiny structures under magnification to appear distinct
    2. Mounting and staining of a specimen
      Mounting. The placing of prepared slide on stage of a microscope;
      Staining. Use of chemical stain on specimen for clear observation
  2. Name the organelle that performs each of the following functions in a cell. 3marks
    1. Transport of packaged glycoproteins
      Golgi bodies
    2. Destruction of worn out cell organelles
      lysosome
    3. Synthesis of proteins
      Ribosomes
  3. Given that the diameter of the field of view of a light microscope is 2000um. Calculate the size of a cell in mm if 10 cells occupy the diameter of the field of view 2marks
    Size of one cell =                 diameter of field view              
                               No. of cells arranged across the diameter
    = 2000μm;
        10cells
    200μm = 0.2mm
    N/B = 1μm = 0.001mms;
  4. State three physiological processes that are involved in movement of substances a cross the cell membrane 3marks
    Osmosis
    Diffusion
    Active transport
  5. The diagram below illustrates the behaviour of red blood cells when placed into two different  solutions X and Y.
    1. Suggest the nature of solutions X and Y. 2marks
      X – hypotonic solution;
      Y – hypertonic solution;
    2. Name the process A and B. 2marks
      A Haemolysis;
      B – crenation
    3. What would happen to normal blood cell if it were placed in an isotonic solution? 2marks
      The cell will maintain/retain its normal shape.
  6. The diagram below represents a cell organelle
    1. Name the part labeled Y 1mark
      Inter grana
    2. State the function of the part labeled X 1mark
      Accept site 4 photolysis; contains chlorophyll pigment that traps light;
  7. Briefly explain the fate of the following products from the light stage of the process of Photosynthesis: 3 marks
    1. Oxygen atoms combines to form oxygen gas used for respiration. The rest is diffused out during gaseous exchange
    2. Hydrogen ions enters the dark stage.
    3. ATP provides energy for carbon(IV) oxide fixation
  8. Name the diseases caused by deficiency of: 2marks
    1. Iodine
      Goiter;
    2. Vitamin C
      Scurvy
  9.        
    1. What is peristalsis? 1 mark
      Involuntary movement of food along the alimentary canal
    2. Explain how the process above is brought about. 2marks
      Occurs when the Circular and longitudinal muscles on the wall of oesophagus and intestines contract and relax alternately;
    3. What are the two functions of bile salts during the process of digestion. 2marks
      Emulsification
      Neutralization of acidic chyme
  10. The table below shows three enzymes A, B and C and their respective optimum pH.
    1. Name the most likely region of the alimentary canal of a mammal where enzyme
      B would be found. 1 mark
      Stomach
    2. Give a reason for your answer in (a) (i) above 2marks
      Presence of hydrochloric acid in the stomach to provide acid conditions
  11. Study the dental formula given below:
    0/4 C0/0 PM3/3 M2/3
    1. Identify with reasons the mode of feeding of the animals whose dental formula is given above
      Mode 1mark
      Herbivorous
      Reasons 2marks
      Lack upper canine and upper incisors
    2. Calculate the total number of teeth in the mouth of the above animal . Show your working.
      2marks.
      15x 2 -= 30 teeth       
  12.      
    1. Define the term transpiration 2marks
      Loss of water inform of water vapour from the plants mainly through the stomata.
    2. State three types of transpiration 3marks
      Stomatal
      Cuticular
      lenticular
    3. List three forces that facilitate the transport of water and mineral salts up the stem. 3marks
      Cohesion and adhesion
      Capillarity
      Root pressure
      Transpiration pull.
    4. Name the tissue that is removed when the bark of a dicotyledonous plant is ringed
      phloem 1 mark
  13. The figure below represents a diagram of a photometer;
    1. What is the photometer used for? 1 mark
      To measure the rate of transpiration in leafy shoot.
    2. give two precautions which should be taken when setting up a photometer 2marks
      Assemble apparatus under water;
      Apply Vaseline between cork shoot contacts;
      Open the reservoir tap;
  14. Name the blood vessel that nourishes the heart 1 mark
    Coronary Artery;
  15. In which form is oxygen transported in the blood. 1 mark
    Oxyhaemoglobin;
  16.        
    1. State three structural differences between arteries and veins in mammals 3 marks
      Arteries Veins
      Thick muscular
      No valves (except at the base of pulmonary artery and aorta)
      Narrow (small) lumen 
      Thin muscular walls
      valves present;
      Wide (large) lumen; 
    2. Name a disease that causes thickening and hardening of arteries 1 mark
      Arteriosclerosis
  17. Explain two advantages of closed circulatory system over open circulatory system. (2marks)
    oxygenated and deoxygenated blood are completely separated / do not mix;
    Blood flow to organs is well regulated based on demand;
    Animals tend to be more active due to efficient transport of gases and nutrients
    Blood circulates over longer distances at faster rate due to high blood presence;
    (mark any 2 correct)
  18. List the components of animal circulatory systems 3 marks
    system of blood vessels in which materials are circulated round the body
    Blood, a fluid medium which contains dissolved substances and cells
    The heart, a pumping mechanism which keeps blood in circulation
  19. Give two structural differences between a red blood cell and a white blood cell. 2 marks.
    Red blood cells • has haemoglobin • smaller size • lacks nucleus
    White blood cells • not pigmented • larger size • nucleated
  20.        
    1. what is blood clotting? 1 mark
      process in which blood components clump together to prevent loss of blood from an injured/cut vessel
    2. Name a protein, vitamin, and an enzyme involved in blood clotting. 3marks
      Protein – fibrinogen/prothrombin
      Vitamin - k/quinine
      Enzyme – thrombokinase/thromboplatin/thrombin
  21.              
    1. What is immunity? 1 mark
      Resistance to disease by organisms
    2. Distinguish between natural and acquired immunity 2 marks
      Natural immunity is inherited/transmitted from parent to offspring/inborn/innate
      Acquired immunity is developed after suffering from a disease or through vaccination
  22. What is the role of vaccination against certain diseases 1 mark?
    protect body against infectious diseases
    prevent spread/transmission of certain diseases

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