Biology Paper 1 Questions and Answers - Sukellemo Joint Mock 2020/2021

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SUKELLEMO JOINT MOCK
Kenya Certificate of Secondary Education
BIOLOGY PAPER 1
(Theory)
2  HOURS

Instructions to Candidates

  • Answer all the questions in the spaces provided.
  1. Name the branch of biology that deals with the of the following
    1. Study of cockroaches, housefly and locusts. (1 mark)
    2. Study of yeast, mushroom, penicillium and toadstools. (1 mark)
  2. Use the diagram below to answer the questions that follow.
    BioSukPP1Q2
    With reasons name the class to which the organism belongs to. (1 mark)
    Class
    Reasons (2 marks)
  3. Some sorghum seeds were soaked in water for two days. They were then broken into small pieces and placed on the surface of agar containing starch. After two days, it was found that the agar no longer contained starch.
    1. How was the test for starch in the agar carried out? (1 mark)
    2. Explain why there was no starch in the agar after two days. (2 marks)
    3. Why were the sorghum seeds broken into smaller pieces? (1 mark)
    4. State the observation made when the seeds were soaked in boiling water. (1 mark)
  4. Under certain conditions, the carbon(IV) oxide concentration in the blood of a mammal rises
    above normal level. State two physiological changes that occur in the body to lower the
    carbon(IV) oxide back to normal. (2 marks)
  5. The diagram below shows a phenomenon which occurs during cell division.
    BioSukPP1Q5
    1. What is the biological importance of the part labelled Z. (2 marks)
    2. Which cell division does the above phenomenon occur? (1 mark)
    3. Name the organs in human beings in which the phenomenon occurs? (1 mark)
  6. The diagram below shows a part of the ear responsible for posture.
    BioSukPP1Q6
    1.    
      1. What is the name of the part shown by the diagram above? (1 mark)
      2. Where in the ear is the part located? (1 mark)
      3. What is the role of the part above? (1 mark)
    2. Name the part labelled C and D. (2 marks)
      C
      D
  7. A layer of glycerine was applied on upper surface of a freshwater floating plant that had been
    kept in the dark for 24 hours. The plant was left undisturbed in bright light. After three hours test for starch carried out on the leaves produced a brown colour of iodine solution. Account for the observation. (3 marks)
  8.  
    1. A plastic container fill of water was stoppered using a piece of stem obtained from a young maize plant whose bark had been peeled off. The next day it was noted that the stopper closed the container very tightly. Explain. (3 marks)
    2.    
      1. State the observation made when a similar experiment was set up but using boiled piece of maize stem obtained from a young maize plant whose bark had been peeled off. (1 mark)
      2. Explain the observation stated in (b) (i) above. (1 mark)
  9. The figure below represents a cell organelle found in the somatic cell of a certain organism.
    BioSukPP1Q9
    1. Name parts labelled F and J. (2 marks)
      F
      J
    2.    
      1. Name the type of mutation illustrated above. (1 mark)
      2. Explain your answer in (b) (i) above. (1 mark)
    3. Determine the total number of chromosomes in a normal gamete cell of the organism.
      (1 mark)
  10. State two functions of calcium in the human body. (2 marks)
  11. Two farmers prepared two ponds Q and R and introduced equal number of fish in each pond. The fish in pond Q died within seven days of being introduced into the pond. Those of pond R survived. On close examination of the ponds, it was found that one of the ponds was full of algae and the other had no algae.
    1. In which of the two ponds were the algae present? (1 mark)
    2. What was the cause of the death of fish in one of the ponds? (1 mark)
    3. State the significance of the algae in the pond? (2 marks)
  12. A form four student was walking around the school compound and saw leaves from nandi flame tree on the ground.
    1. Name the hormone responsible for this phenomenon. (1 mark)
    2. State the significance of the above phenomenon to the tree. (2 marks)
  13. The figure below shows the change in the concentration of various substances in a river following the discharge of untreated sewage into it.
    BioSukPP1Q13
    1. Account for the changes in concentration of:
      1. Organic matter. (1 mark)
      2. Nutrient ions. (1 mark)
      3. Dissolve oxygen. (1 mark)
    2. Describe the changes expected in:
      1. Fish population between the point of sewage discharge and the point where the organic matter returns to normal levels. (1 mark)
      2. Water plants and photosynthetic algae about one and half kilometres downstream from the point of sewage discharge. (1 mark)
  14. Short-horned grasshopper moults five times before reaching adult size. Draw the kind of growth curve you would expect for the grasshopper if the changes in its length are plotted against time.
    (2 marks)
  15. Wet cotton wool was put in two flasks M and N. Soaked seeds are added to M and an equal
    number of boiled seeds to N. Both groups of seeds were first soaked in sodium hypochlorite
    solution before being put in the flasks. The flasks were securely corked and left in the same
    conditions of light and temperature for ten days. The cork from each flask was removed and each tilted over a test-tube of calcium hydroxide solution as shown in T.
    BioSukPP1Q15
    1. What was the aim of the experiment? (1 mark)
    2. Explain the observations made in Flask M and N. (3 marks)
      M
      N
    3. Why were the seeds soaked in sodium hypochlorite for fifteen minutes? (1 mark)
  16. The diagram below shows section through the flower of a certain plant.
    BioSukPP1Q16
    1.    
      1. To which class does the plant from which the flower was obtained belong to? (1 mark)
      2. State the reason for your answer in (a)(i) above. (1 mark)
    2. State the placetation. (1 mark)
    3.    
      1. Name the part labelled K. (1 mark)
      2. What is the fate of the part labelled S during fruit development? (1 mark)
  17. State two ways in which the skeletal muscle fibres are adapted to their function. (2 marks)
  18. State the functions of lymph nodes. (2 marks)
  19. The following diagrams represent different animal structures.
    BioSukPP1Q19
    1.    
      1. What type of structures are represented by the diagram above? (1 mark)
      2. Give a reason for your answer in (a) (i) above. (1 mark)
      3. Name the evolutionary phenomenon represented by the structures. (1 mark)
    2. Explain comparative serology as an evidence of evolution. (2 marks)
  20. A form four student was found to have blood group AB+.
    1. What antigens does this blood group have? (1 mark)
    2. What antibodies are present in the blood? (1 mark)
    3. The student was injured and required blood transfusion. Which blood groups can he receive the blood from? (1 mark)
  21. The diagram below illustrates the variation in atmospheric temperature in the course of a day and the body temperature of two animals A and B. Study it and answer the questions that follow.
    BioSukPP1Q21
    1. Describe how animal A regulates its body temperature between 12 noon and 6.00 pm. (3 marks)
    2. State the activities that account for the body temperature of animal B between 9.00 am and 6.00 pm. (1 mark)
  22.    
    1. State two adaptations that enable birds to fly. (2 marks)
    2. State two functions of the cuticle in insects. (2 marks)

MARKING SCHEME

  1. Name the branch of biology that deals with the of the following
    1. Study of cockroaches, housefly and locusts. (1 mark)
      • Entomology;
    2. Study of yeast, mushroom, penicillium and toadstools. (1 mark)
      • Mycology;
  2. Use the diagram below to answer the questions that follow.
    BioSukPP1Q2
    With reasons name the class to which the organism belongs to. (1 mark)
    Class - Chilopoda; Rej – if starting with a small letter
    – wrong spelling

    Reasons (2 marks)
    • Has two body parts;
    • Has one pair of walking legs per segment;
    • Has long pair of antennae;
      (Reasons tied to class)
  3. Some sorghum seeds were soaked in water for two days. They were then broken into small pieces and placed on the surface of agar containing starch. After two days, it was found that the agar no longer contained starch.
    1. How was the test for starch in the agar carried out? (1 mark)
      • Add three drops of iodine on the agar the colour of iodine remained brown indicating absence of starch in the agar;

    2. Explain why there was no starch in the agar after two days. (2 marks)
      • Sorghum seed contain (enzyme) amylase/ptyalin (acc diastase); which converted/digested/hydrolysed/break down starch in the agar to maltose;

    3. Why were the sorghum seeds broken into smaller pieces? (1 mark)
      • To increase surface area for working/activity/action of enzyme;

    4. State the observation made when the seeds were soaked in boiling water. (1 mark)
      • Brown iodine solution changes colour to blue-black since starch is not digested because the enzyme is denatured by boiling/high temperatures;

  4. Under certain conditions, the carbon(IV) oxide concentration in the blood of a mammal rises
    above normal level. State two physiological changes that occur in the body to lower the
    carbon(IV) oxide back to normal. (2 marks)
    • Inspiration/inhalation and expiration/exhalation rate will increase;
    • Heartbeat/rate of blood circulation will increase;

  5. The diagram below shows a phenomenon which occurs during cell division.
    BioSukPP1Q5
    1. What is the biological importance of the part labelled Z. (2 marks)
      • Non sister chromatids cross over and exchange genes; leading to genetic variation/recombination;

    2. Which cell division does the above phenomenon occur? (1 mark)
      • Meiosis;

    3. Name the organs in human beings in which the phenomenon occurs? (1 mark)
      • Testes/ovaries;

  6. The diagram below shows a part of the ear responsible for posture.
    BioSukPP1Q6
    1.    
      1. What is the name of the part shown by the diagram above? (1 mark)
        • Ampulla (organ);

      2. Where in the ear is the part located? (1 mark)
        • Semi-circular canal(s);

      3. What is the role of the part above? (1 mark)
        • Maintenance body balance and posture in relation to movement of the head;

    2. Name the part labelled C and D. (2 marks)
      C - (Gelatinous) cupula;
      D - Sensory cell(s);

  7. A layer of glycerine was applied on upper surface of a freshwater floating plant that had been kept in the dark for 24 hours. The plant was left undisturbed in bright light. After three hours test for starch carried out on the leaves produced a brown colour of iodine solution. Account for the observation. (3 marks)
    • The leaf had stomata only on the upper surface; which were blocked by glycerine cutting supply of carbon(IV) oxide; no photosynthesis takes place hence absence of starch;
  8.  
    1. A plastic container fill of water was stoppered using a piece of stem obtained from a young maize plant whose bark had been peeled off. The next day it was noted that the stopper closed the container very tightly. Explain. (3 marks)
      • Vacuole of the cortical/inner cells of the stem was hypertonic to the water; the inners/cortical cells absorbed water by osmosis; and became turgid increasing in size closing the container very tightly;
    2.    
      1. State the observation made when a similar experiment was set up but using boiled piece of maize stem obtained from a young maize plant whose bark had been peeled off. (1 mark)
        • stem stopper remains the same/ does not close the container very tightly;

      2. Explain the observation stated in (b) (i) above. (1 mark)
        • Boiling destroys the cell membrane of the stem cells preventing osmosis from occurring; Tied to (b) (i)

  9. The figure below represents a cell organelle found in the somatic cell of a certain organism.
    BioSukPP1Q9
    1. Name parts labelled F and J. (2 marks)
      F - Nuclear pore
      J - Chromatid
    2.    
      1. Name the type of mutation illustrated above. (1 mark)
        • Non-disjunction;

      2. Explain your answer in (b) (i) above. (1 mark)
        • Has extra chromosome labelled H;

    3. Determine the total number of chromosomes in a normal gamete cell of the organism.
      (1 mark)
      • 3/three chromosomes;

  10. State two functions of calcium in the human body. (2 marks)
    • Contraction of muscles;
    • Formation of strong /teeth;

  11. Two farmers prepared two ponds Q and R and introduced equal number of fish in each pond. The fish in pond Q died within seven days of being introduced into the pond. Those of pond R survived. On close examination of the ponds, it was found that one of the ponds was full of algae and the other had no algae.
    1. In which of the two ponds were the algae present? (1 mark)
      • Pond R (Acc – pond in which the fish survived);

    2. What was the cause of the death of fish in one of the ponds? (1 mark)
      • Inadequate oxygen (in the water for respiration)

    3. State the significance of the algae in the pond? (2 marks)
      • Reduce carbon(IV) oxide concentration in the water;
      • Increases oxygen concentration in the water;
      • Provide food for the fish/animals;
      • Provide shelter for the fish;

  12. A form four student was walking around the school compound and saw leaves from nandi flame tree on the ground.
    1. Name the hormone responsible for this phenomenon. (1 mark)
      • Absciscic acid;

    2. State the significance of the above phenomenon to the tree. (2 markS)
      • Reduce (the rate of) transpiration;
      • Excretion;

  13. The figure below shows the change in the concentration of various substances in a river following the discharge of untreated sewage into it.
    BioSukPP1Q13
    1. Account for the changes in concentration of:
      1. Organic matter. (1 mark)
        • Saprophytic bacteria breakdown the organic matter (into soluble simple materials) leading to decrease (in amount of) organic matter downstream;

      2. Nutrient ions. (1 mark)
        • Breakdown of organic matter by saprophytic bacteria releases nutrients/nitrates/ammonium/phosphates/sulphates increasing concentration of ions in the water;

      3. Dissolve oxygen. (1 mark)
        • Saprophytic bacteria use up dissolved oxygen for respiration decreasing the amount of oxygen in the river upstream;
        • Downstream the level of organic matter decreases decreasing activity of saprophytic bacteria increasing the level of oxygen to normal;
          (Award the any one)

    2. Describe the changes expected in:
      1. Fish population between the point of sewage discharge and the point where the organic matter returns to normal levels. (1 mark)
        • Fish population decreases(drastically) due to insufficient oxygen/decrease in oxygen concentration;

      2. Water plants and photosynthetic algae about one and half kilometres downstream from the point of sewage discharge. (1 mark)
        • water plant and algae proliferate/increase due to increase in nutrients/phosphates/nitrates due to breakdown of organic matter by saprophytic bacteria;

  14. Short-horned grasshopper moults five times before reaching adult size. Draw the kind of growth curve you would expect for the grasshopper if the changes in its length are plotted against time.(2 marks)
    BioSukPP1A14
  15. Wet cotton wool was put in two flasks M and N. Soaked seeds are added to M and an equal number of boiled seeds to N. Both groups of seeds were first soaked in sodium hypochlorite solution before being put in the flasks. The flasks were securely corked and left in the same conditions of light and temperature for ten days. The cork from each flask was removed and each tilted over a test-tube of calcium hydroxide solution as shown in T.
    BioSukPP1Q15
    1. What was the aim of the experiment? (1 mark)
      • To show that carbon(IV) oxide is produced by germinating seeds;

    2. Explain the observations made in Flask M and N. (3 marks)
      M - Germinating seeds used up oxygen in the flask for respiration; producing carbon(IV) oxide which forms a white precipitate with calcium hydroxide solution;

      N - Boiled seeds did not respire no carbon(IV) oxide was produced hence the calcium hydroxide solution remained clear/ no white precipitate formed in calcium hydroxide solution;

    3. Why were the seeds soaked in sodium hypochlorite for fifteen minutes? (1 mark)
      • To kill bacteria/ fungi which may produce carbon(IV) oxide;

  16. The diagram below shows section through the flower of a certain plant.
    BioSukPP1Q16
    1.    
      1. To which class does the plant from which the flower was obtained belong to? (1 mark)
        • Dicotyledonae;

      2. State the reason for your answer in (a)(i) above. (1 mark)
        • Presence of four stamen; Tied to (a)(i)

    2. State the placetation. (1 mark)
      • Marginal( placentation);
    3.    
      1. Name the part labelled K. (1 mark)
        • Sepal/calyx;

      2. What is the fate of the part labelled S during fruit development? (1 mark)
        • Develop into seeds;

  17. State two ways in which the skeletal muscle fibres are adapted to their function. (2 marks)
    • Have actin and myosin/actomyosin/sacromeres/contractile proteins which cause contraction and relaxation of the muscle;
    • High density of mitochondria to provide energy for contraction;
    • Elongated fibres/long myofibrils to allow maximum change in length;

  18. State the functions of lymph nodes. (2 marks)
    • Production of lymphocytes (Acc –Agranulocytes);
    • Trap and destroy pathogens;

  19. The following diagrams represent different animal structures.
    BioSukPP1Q19
    1.    
      1. What type of structures are represented by the diagram above? (1 mark)
        • Analogous structures;
      2. Give a reason for your answer in (a) (i) above. (1 mark)
        • Have different basic structure but are modified to perform the same function;

      3. Name the evolutionary phenomenon represented by the structures. (1 mark)
        • Convergent evolution;

    2. Explain comparative serology as an evidence of evolution. (2 marks)
      • The immunological reactions form a precipitate; – The higher the precipitate the closer the relationship between the animals being compared;

  20. A form four student was found to have blood group AB+.
    1. What antigens does this blood group have? (1 mark)
      • Antigen A, antigen B, Rhesus antigen; Acc –only where all are present.

    2. What antibodies are present in the blood? (1 mark)
      • None;

    3. The student was injured and required blood transfusion. Which blood groups can he receive the blood from? (1 mark)
      • AB+, AB-, O+, O-; Acc– only where all are present

  21. The diagram below illustrates the variation in atmospheric temperature in the course of a day and the body temperature of two animals A and B. Study it and answer the questions that follow.
    BioSukPP1Q21
    1. Describe how animal A regulates its body temperature between 12 noon and 6.00 pm. (3 marks)
      • Erector pilli muscles contract lowering hair on the skin less air is trapped increasing heat loss;
      • Dilation of superficial arteries increasing blood flow near the surface of the skin leading to increase in heat loss;
      • More sweating leading to evaporation of sweat from skin leads to heat loss;

    2. State the activities that account for the body temperature of animal B between 9.00 am and 6.00 pm. (1 mark)
      • Going under a shade/burrowing;

  22.    
    1. State two adaptations that enable birds to fly. (2 marks)
      • Hollow bones to make them light;
      • Have a large keel to increase surface area for attachment of pectoral/flight muscles;

    2. State two functions of the cuticle in insects. (2 marks)
      • Protection from mechanical damage;
      • Waxy to reduce water loss;

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