Biology Questions and Answers - Form 3 Opener Term 1 Exams 2022

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BIOLOGY

INSTRUCTIONS.
Answer all the questions in the spaces provided.



Questions

  1.          
    1. Name two external features found in class mammalia only. (2mks)
    2. Name the taxonomic unit that comes immediately after a phylum in classification. (1mk)
  2. The diagram below represents a plant in the division Bryophyta.
    BioF3ot1q2
    1. Name the parts labeled B and D. (2mks)
    2. State one function of the parts labeled A and C. (2mks)
  3. A student collected an organism and observed the following features.
    1. Simple eyes, four pairs of legs and two body parts.
      1. State the class to which the organism belongs. (1mk)
      2. Give an example of an organism in this class. (1mk)
      3. Name the kingdom to which plasmodium belongs. (1mk)
  4. List the three branches of biology. (3mks)
  5.       
    1. Give the formula used to calculate magnification in a light microscope. (1mk)
    2. Give the reasons for each of the following steps when preparing a cross-section of a stem or leaf for examination under the microscope. (3mks)
      1. Cutting very thin sections
      2. Using sharp razor blade during the cutting.
      3. Placing sections in water
  6. The diagrams below show a red blood cell that was subjected to a certain treatment.
    BioF3ot1q6
    1. Account for shape of the cell at the end of the experiment. (2mks)
    2. Draw a diagram to illustrate how a plant cell would appear if subjected to the same treatment. (1mk)
  7. The diagram below represents a transverse section through a plant organ.
    BioF3ot1q7
    1. From which plant organ was the section obtained. (1mk)
    2. Give two reasons for your answer in (a) above. (2mks)
    3. Name the parts labeled J, K and L. (3mks)
  8.        
    1. Give two advantages of being a homoeotherm. (2mks)
    2. If a person’s pancreas is not functional:
      1. What hormones may be deficient in the person? (2mks)
      2. Name the disease the person is likely to suffer. (1mk)
  9. Study the word equation below.
    Glucose → Ethanol + carbon (IV) oxide + ATP
    1. Name the process shown in the equation above. (1mk)
    2. Suggest the organism(s) in which it takes place. (1mk)
    3. Give two application of the process in industry. (2mks)
  10. Study the diagram below and answer the questions that follow.
    BioF3ot1q10
    1. Name the parts labeled A and B. (2mks)
    2. How are the parts labeled A adapted to their functions. (3mks)
  11. State one function of each of the following cell organelles.
    1. Golgi bodies (1mk)
    2. Lysosomes (1mk)
    3. Ribosomes (1mk)
  12. The following is the dental formula of a certain mammal.
    i        0               c0              Pm3            m3
             3                 1               3                 3
    1. State the likely mode of feeding for the mammal. (1mk)
    2. Give a reason for your answer in (a) above. (1mk)
    3. Name two dental diseases. (2mks)
  13. A person whose blood group is AB requires a transfusion. Name the blood groups of possible donors. (2mks)
  14. Name a vitamin, an enzyme and a mineral element that are involved in blood clotting. (3mks)
    Vitamin
    Enzyme
    Mineral element
  15. Name the process by which each of the following occurs.
    1. Molecules such as amino acids and glucose enter the body cell. (1mk)
    2. Glucose and mineral salts are re-absorbed into the blood in the kidney. (1mk)
    3. Water is absorbed from soil by root hairs. (1mk)
    4. Carbon (IV) oxide moves from the body cells to the blood capillaries. (1mk)
  16. The diagram below shows part of the respiratory system of a certain animal.
    1. Name the structure labeled A and state its functions. (2mks)
      Structure
      Function
    2. What is the advantage of the ringed structured labeled B. (1mk)
  17. The equation below shows the oxidation reaction of food substances.
    5C(s)H98O6 + 145O2 → 102CO2 + 98 H2O + energy
    1. What do you understand by the term respiratory quotient? (1mk)
    2. Determine respiratory quotient of the oxidation of food substance. (2mks)
    3. Identify the food substances. (1mk)
  18.      
    1. Explain why pepsin in stomach of man is secreted in inactive form. (1mk)
    2. Which gland secrets pepsinogen? (1mk)
    3. The diagram below illustrated a physiological process that occurs in the alimentary canal of man.
      BioF3ot1q18c
      1. Name the process Q above. (1mk)
      2. Explain the biological significance of the above process. (1mk)
      3. Name the substance that helps the process named in (i) above. (1mk)
  19. Besides venation, state two other external characteristics of leaves that can be used to classify plants. (2mks)


Marking Scheme

  1.        
    1. Name two external features found in class mammalia only. (3mks)
      • Have mammary glands
      • Have external ears, two pinnae
      • Body covered by hair or fur

    2. Name the taxonomic unit that comes immediately after a phylum in classification. (1mk)
      • Class

  2. The diagram below represents a plant in the division Bryophyta.
    1. Name the parts labeled B and D. (2mks)
      • B - Seta
      • D - Rhizoid

    2. State one function of the parts labeled A and C. (2mks)
      • A - Production of spores
      • C - Photosynthesis

  3. A student collected an organism and observed the following features.
    1. Simple eyes, four pairs of legs and two body parts.
      1. State the class to which the organism belongs. (1mk)
        • Arachnida

      2. Give an example of an organism in this class. (1mk)
        • Spider, scorpion, tick, mite

    2. Name the kingdom to which plasmodium belongs. (1mk)
      • Protoctista / Protista rej Wrong sp p should be capital

  4. List the three branches of biology. (3mks)
    • Zoology
    • Betany
    • Microbiology
  5.              
    1. Give the formula used to calculate magnification in a light microscope. (1mk)
      • Eye piece lens magnification x objective lens magnification

    2. Give the reasons for each of the following steps when preparing a cross-section of a stem or leaf for examination under the microscope. (3mks)
      1. Cutting very thin sections
        • Thin sections allow light to pass through making it easy to observe the tissue.

      2. Using sharp razor blade during the cutting.
        • Sharp blade doesn’t damage, deform or distort surface of cell.

      3. Placing sections in water
        • To maintain turgidity hence maintain shape of cell.
        • It prevents drying of the section.

  6. The diagrams below show a red blood cell that was subjected to a certain treatment.
    1. Account for shape of the cell at the end of the experiment. (2mks)
      • The RBC was place in a hypertonic solution. It lost water by osmosis and become crenated.

    2. Draw a diagram to illustrate how a plant cell would appear if subjected to the same treatment. (1mk)

  7. The diagram below represents a transverse section through a plant organ.
    1. From which plant organ was the section obtained. (1mk)
      • Root

    2. Give two reasons for your answer in (a) above. (2mks)
      • Presence of root hairs, xylem star shaped at centre, phloem in arms.
      • Presences of endodermis of xylem.

    3. Name the parts labeled J, K and L. (3mks)
      • J – Epidermis
      • K – Phloem
      • L- Xylem
  8.                  
    1. Give two advantages of being a homeotherm. (5mks)
      • They can survive extreme climatic conditions or changes.
      • They are active always.

    2. If a person’s pancreas is not functional:
      1. What hormones may be deficient in the person? (2mks)
        • Insulin
        • Glucagon

      2. Name the disease the person is likely to suffer. (1mk)
        • Diabetes mellitus

  9. Study the word equation below.
    Glucose → Ethanol + carbon (IV) oxide + ATP
    1. Name the process shown in the equation above. (1mk)
      • Anaerobic respiration

    2. Suggest the organism(s) in which it takes place. (1mk)
      • Plants

    3. Give two application of the process in industry. (2mks)
      • Baking of bread
      • Brewing
      • Production of biogas and gasohol
      • Formation of fossil fuel
      • Manufacture of dairy products
      • Treatment of sewage
      • Production of silage

  10. Study the diagram below and answer the questions that follow.
    1. Name the parts labeled A and B. (2mks)
      • A – Gill filaments
      • B – Gill rakers

    2. How are the parts labeled A adapted to their functions. (3mks)
      • They are moist to dissolve respiratory gases.
      • They have a thin membrane to reduce distance across which gases diffuse.
      • They are many to increase Surface area for gaseous exchange
      • They have many blood capillaries to increase the surface area for diffusion and transport of gases.

  11. State one function of each of the following cell organelles.
    1. Golgi bodies (1mk)
      • Form lysosomes, packing of synthesized materials.

    2. Lysosomes (1mk)
      • Contains lytic enzymes and destroy worn out cells/organelles.

    3. Ribosomes (1mk)
      • Site for protein synthesis.

  12. The following is the dental formula of a certain mammal.
    1. State the likely mode of feeding for the mammal. (1mk)
      •  Herbivorous

    2. Give a reason for your answer in (a) above. (1mk)
      • Lack canines/ incisors on upper jaw.

    3. Name two dental diseases. (2mks)
      • Dental carries
      • Periodontal disease/ periodontis i.e. gingivitis or pyorrhoea

  13. A person whose blood group is AB requires a transfusion. Name the blood groups of possible donors. (2mks)
    • Blood group AB, A, B and O (mention all)

  14. Name a vitamin, an enzyme and a mineral element that are involved in blood clotting. (3mks)
    • Vitamin – k
    • Enzyme – thromboplastin, thrombin
    • Mineral element - calcium

  15. Name the process by which each of the following occurs.
    1. Molecules such as amino acids and glucose enter the body cell. (1mk)
      • Diffusion

    2. Glucose and mineral salts are re-absorbed into the blood in the kidney. (1mk)
      • Active transport and diffusion

    3. Water is absorbed from soil by root hairs. (1mk)
      • Osmosis

    4. Carbon (IV) oxide moves from the body cells to the blood capillaries. (1mk)
      • Diffusion

  16. The diagram below shows part of the respiratory system of a certain animal.
    1. Name the structure labeled A and state its functions. (2mks)
      • Structure – spiracle
      • Function – It lets air in and out of the trachea

    2. What is the advantage of the ringed structured labeled B. (1mk)
      • For support: it prevents the trachea from collapsing.

  17. The equation below shows the oxidation reaction of food substances.
    1. What do you understand by the term respiratory quotient? (1mk)
      • Ratio showing the amount of carbon (IV) oxide produced against the volume of oxygen consumed.

    2. Determine respiratory quotient of the oxidation of food substance. (2mks)
      • RQ=     CO2 Produced         RQ=    102   =0.7
             Oxygen Consumed                     145

    3. Identify the food substances. (1mk)
      • Fats

  18.                
    1. Explain why pepsin in stomach of man is secreted in inactive form. (1mk)
      • To avoid digestion of stomach wall.

    2. Which gland secrets pepsinogen? (1mk)
      • Gastric gland

    3. The diagram below illustrated a physiological process that occurs in the alimentary canal of man.
      1. Name the process Q above. (1mk)
        • Emulsification

      2. Explain the biological significance of the above process. (1mk)
        • Increase surface area for fat digestion.

      3. Name the substance that helps the process named in (i) above. (1mk)
        • Bile salts

  19. Besides venation, state two other external characteristics of leaves that can be used to classify plants. (2mks)
    • Leaf margin
    • Leaf tip
    • Leaf pestiole
    • Leaf form
    • Leaf shape

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