Biology Paper 1 Questions and Answers - Cekena Pre Mocks 2022

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  • Write your name, admission number, date, and signature and school name in the spaces provided
  • Answer all the questions
  • Answers must be written in spaces provided
  • This paper consists of 12 printed pages Candidates should check the question paper to ascertain that all pages are printed as indicated and that no questions are missing












    1. Define the term specimen (1mk)
    2. Give two significances of collecting specimens in biology (2mks)
  2. Give three reasons why Drosophila melanogaster is considered suitable for use in genetic experiments (3mks)
  3. List two factors you would consider before selecting a microscope for use in a biological study (2mks)
  4. A group of form two students placed a fresh leaf in warm water They observed that air bubbles formed on the surface of the leaf
    1. What biological process were they investigating? (1mk)
    2. Name the structures from which the air bubbles were coming from (1mk)
    3. Explain the distribution of the structures named in (b) above on the leaf surfaces of an aquatic plant (2mks)
  5. Differentiate between hydrolysis and condensation (2mks)
    1. Which sets of teeth would be used in chewing sugarcane for maximum extraction of sap? (2mks)
    2. What is the advantage of heterodont dentition over homodont dentition? (1mk)
    3. During digestion name the enzyme that acts on the sugarcane sap and give the final products (2mks)
      Final products
  7. Study the diagram below and answer the questions that follow
    7 dddaada
    1. The part labelled X turned blue black after iodine solution was applied on the cut cross section of the above specimen
      1. Name part X (1mks)
      2. Give a reason for your answer (1mks)
    2. State two phenomenons of stomata which reduce the rate of transpiration (2mks)
    1. What is respiratory quotient? (1mks)
    2. Explain why it is difficult to measure respiratory quotient in plants (2mks)
  9. Study and complete the table below (3mks)




    a) Number of stamens


    b) Arrangement of vascular bundle in stem


    c) Type of root

  10. The diagram below shows blood circulation in a mammalian tissue
    10 sfsfsfs
    1. Give the name of the above section of the blood circulation system (1mks)
    2. Explain two the adaptation of the above section to its function (2mks)
    3. What is the name of blood vessel Q (1mk)
  11. Differentiate between dioecious and monoecious plants (2mks)
    1. Why does endosperm weight of a germinating seed decrease as the weight of the shoot increases (1 mks)
    2. State three importance of the pupa stage of metamorphosis to insects (1 mks)
  13. The diagrams below show a pair of homologous chromosomes Study them and answer the questions that follow
    13 sdsfsfs
    1. State the phenomenon shown above (1 mk)
    2. What is the genetic significance of the phenomenon above? (1 mk)
    3. Name the type of mutation caused by the above phenomenon (2mks)
  14. In an experiment to determine the population of Tilapia fish in a school fish pond, students of Canada school decided to use capture-recapture method
    1. Name three vital tools the students would need for the exercise (3mks)
    2. State two factors that might affect the accuracy of their results (2mks)
  15. The table below show description of sizes of glomeruli and renal tubules of two animals, which are in different environments

    Animal Q

    Animal W




    Renal tubules



    1. Name the likely environment in which each animal lives (2mks)
      Q –
    2. Suggest the main nitrogenous waste produced by animal W (1 mk)
    3. What is the importance of the renal tubules being long? (1 mk)
  16. What is the role of the following hormones in human reproduction?
    1. Follicle stimulating hormone in male (1 mk)
    2. Luteinizing hormone during menstrual cycle (1 mk)
  17. Below is representation of an experiment that was carried out on a tree in Kayombe forest
    17 sdadaadd
    1. Which two tissues are removed in a ring bark experiment? (2mks)
    2. Removal of the tissues above leads to some effects to the plant Name these 2 effects (2mks)
    3. State and explain the observation that would be made in the plant above after some time (3mks)
  18. A section of nucleic strand contains the following sequence
    A — C —  G — A — G — A — T — A— C
      1. Write the complimentary DNA stand (1 mk)
      2. Write the mRNA strand of the strand in (a) above (1 mk)
    2. Name the site for protein synthesis in a cell (1 mk)
    3. State one disorder caused by non-disjunction mutation (lmk)
    1. State the importance of rings of chitin in the tracheal system of insects (1 mk)
    2. Explain the significance of maintaining a steep concentration gradient in the respiratory surfaces of animals (1 mk)
    3. Explain why a bony fish dies shortly after being removed from water (3mks)
  20. Explain why Lamark’s theory of evolution is not accepted by modern scientist (2mks)
  21. Name the branch of biology that deals with;
    1. Relationship between antelopes and gazelles in their environment (1 mk)
    2. Study of Ebola virus (1 mk)
    3. Explain what would happen if a given of living things lose their ability to reproduce (1 mk)
  22. Explain the following when testing a leaf for starch
    1. Boiling the leaf in hot water (1 mk)
    2. Destarching (1 mk)
    3. Boiling the leaf in methylated spirit (1 mk)
  23. Explain why osmosis is a special type of diffusion (1 mk)
  24. Explain three protective functions of the blood (3mks)


    1. This is a part of an organism or the whole organism selected for detailed scientific study.
      • Saves time during studies
      • Enhances detailed study of biological concepts
    • The female lays many eggs hence increases the sample size for study.
    • Have many observable characteristics that are distinct and contrasting.
    • It is easily bred in the laboratory with minimum requirements.
    • Has a short generation time (life span) of 10-13 days hence a short study period.
    • Offspring can easily be selfed and also be crossed with their parents easily (backcrossing)
    • The flies are safe to handle because they do not transmit any known human disease.
    • Magnification power
    • Resolution power
    1. Gaseous exchange
    2. Stomata
    3. Aquatic plants have stomata on the upper part of the leaves; to increase high rate of transpiration to encourage excess loss of excess water;
  5. Hydrolysis — process by which complex molecules are broken to simpler molecules;
    While, condensation is the process by which simple molecules are combined to form complex compounds with formation of water.
    1. Premolars and molars
    2. Organisms with heterodont dentition can feed on a variety of diet.
    3. Enzyme — sucrase
      Final product — glucose and fructose
      1. Endodermis
      2. Has starch grains which turns blue black when stained with iodine solution
      • Sunken stomata
      • Reversed stomatal rhythm
      • Midday closure
      • Reduced number of stomata on upper surface of the leaf; (first two correct points)
    1. Respiratory quotient (RQ) is a ratio showing the relationship between the amounts of carbon (IV) oxide used against the amount of oxygen used in respiration.
    2. Oxygen produced by photosynthesis process is used for respiration and the carbon (IV) oxide produced in respiration is utilized in photosynthesis
  9. Character



    a) Number of stamens

    In multiple of three

    Multiples of 4/5

    b) Arrangement of vascular bundle in stem

    Vascular bundle are scattered

    Vascular bundle arranged in a ring

    c) Type of root


    Tap root

    1. Blood capillaries
      • Their walls are made up of one cell thick therefore providing a short distance for exchange of substances.
      • Narrow lumen to creating high pressure which forces the fluid part of the blood to filter out of through the capillary walls (ultra filtration) into the intercellular space forming the tissue fluid
      • Highly divided to increase the surface area for exchanging materials
    3. Venule
    1. Dioecious plant — plant with separate sexes, i.e has either male or female reproductive organ; monoecious — plant with both male and female flowers borne on the same plant.
    1. Food stored in the cotyledon is hydrolysed and transported to the plumule is used in growth of the shoot which leads to an increase in weight
      • Enables them to survive adverse environmental condition
      • Non-feeding stage therefore reduces competition for food among insects
      • Allow for extensive breakdown and reorganization of tissues to give rise to an adult/imago. (First three points) (3 mks)
    1. Chiasmata formation
    2. Leads to exchange of genetic materials which causes variation in organisms
    3. Chromosomal mutation-Translocation mutation
    1. Fish net Rej. Fishing net
      • Water proof ink
      • Data collection Notebook
      • Can lead to underestimation/overestimation
      • Birth/death may occur before second capture is done
      • Method marking may interfere with organisms way of life
    1. Q- Arid and semi-arid
      W- Aquatic
    2. Ammonia
    3. To increase the surface area for reabsorption of water in the kidney tubules for them to conserve water.
    1. Synthesis and maturation of sperms
    2. Stimulates the maturation of Graafian follicle
    1. Phloem
      • Increased risk of infections
      • Inability to translocate manufactured food downward the plant.
    3. Swelling on the upper part of the ring; since ringing removed the phloem; hence manufactured food is not translocated downwards
      1. T—G— C—T—C— T—A—T—G
      2. U—G—C—U—C—U—A— U—G
    2. Ribosomes
      • Turner’s syndrome
      • Down’s syndrome
      • Klinefelter’s syndrome
    1. Keep the trachea open preventing them from collapsing;
    2. Maintain a high rate of diffusion of respiratory gases for maximum gaseous exchange;
    3. When fish is lifted out of water, the gills filaments clumps together; reducing their surface area; for gaseous exchange; (this causes death) / Also in air, the moisture evaporates fast from the gill filaments; since gaseous exchange requires moist surfaces; the diffusion of oxygen and carbon (IV) oxide cannot take place;
  20. The acquired characteristics are not inherited; since the traits are found in somatic cells only
    1. Ecology
    2. Virology
    3. They will become extinct with time
    1. To kill the protoplasm/stop any enzymatic reaction that could use starch
    2. Remove starch that was initially present thus ensuring that starch if present can only be attributed to factor under investigation.
    3. To remove chlorophyll from the leaf to track colour changes when iodine solution is added.
  23. Involves movement of water molecules only from a region of high water concentration to region of low water concentration through a semi-permeable membrane.
    • Granulocytes and monocytes engulf the pathogens destroying them.
    • Lymphocytes produce antibodies which destroys the pathogens.
    • Platelets enhance the clotting process to occur thus preventing entry of pathogens.
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