Biology Paper 1 Questions and Answers - Asumbi Girls High School KCSE Mock 2021

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Instructions to candidates

  • Answer all the questions in this paper.


    1. State two external features found in class Mammalia only. (2mks)
    2. Name the taxonomic unit that comes immediately after Family in classification. (1mk)
    1. Name the basic functional unit of the skeletal muscle. (1mk)
    2. Distinguish between a tendon and a ligament. (1mk)
    1. State two advantages of using a coverslip when preparing a specimen for observation under the light microscope. (2mks)
    2. How is the low power objective lens manipulated to focus a specimen for observation under a light miscroscope? (2mks)
  4. Explain the significance of the following in the feeding of a mammal
    1. Long tongue in herbivores. (1mk)
    2. Canine in carnivores. (1mk)
  5. Name the part of maize seed that elongates to bring about hypogeal germination. (1mk)
    1. State two characteristics of living organisms that are specific to plants. (2mks)
    2. State the name given to the study of;
      1. The cell (1mk)
      2. Microorganisms (1mk)
  7. What is the function of the following structures in the human reproductive organs;
    1. Fallopian tubes (1mk)
    2. Epididymis (1mk)
    3. Scrotal sac (1mk)
  8. Under what conditions do animals use the following food for respiration;
    1. Carbohydrates (1mk)
    2. Fats (1mk)
    3. Tissue proteins (1mk)
  9. Distinguish between convergent and divergent evolution (1mk)
  10. Fingerlings of fish were introduced to two different ponds. Those fingerlings in pond one all died within four days but the fingerlings in pond two survived. Suggest the likely reasons why the fingerlings in one pond died. (3mks)
    1. State the functions of the following parts of a light microscope
      1. Objective lens (1mk)
      2. Fine adjustment knob (1mk)
    2. Using a microscope a student counted 66 cells across the field of view whose diameter was 6000m. Calculate the average length of cells. Show your working.
  12. Why is a change in dry mass of an organism the best indicator of growth? (2mks)
  13. Other than the visceral organs in the body name two other parts of the body where smooth muscles are found. (2mks)
  14. State the role of each of the following components of skin
    1. Melanin (1mk)
    2. Sebum (1mk)
    3. Adipose tissue. (1mk)
  15. How does a sunken stomata help a plant avoid excessive water during gaseous exchange? (3mks)
  16. Name the substances produced as a result of anaerobic respiration in
    1. Yeast (1mk)
    2. Human muscles (1mk)
  17. Why is Lamarck’s theory of evolution not accepted by biologist today? (2mks)
  18. Give two reasons why animals have specialised organs for excretion as compared to plants. (2mks)
  19. The diagram below illustrate a response by a certain plant
    1. Name the type of response (1mk)
    2. Explain how the response illustrated above occurs (3mks)
    1. What is meant by the term wilting. (1mk)
    2. Explain how an increase in temperature affects the rate of active transport. (2mks)
  21. Explain four adaptive characteristics features of respiratory surfaces. (4mks)
    1. State two advantages of complete metamorphosis to the life cycle of an insect. (2mks)
    2. Distinguish between primary and secondary growth in plants (2mks)
  23. The table below shows the level of two gases X and Y, in blood entering and leaving the lungs during the process of gas exchange.
    Gas  Level of gas in cm3 per/100cm of blood
    Blood entering lungs Blood leaving lungs
     10.6  19.0
    Y  58.0  50.0

    1. Name gases X and Y. (2mks)
    2. How much gas X enters 100cm3 of blood, before the blood leaves the lungs. (2mks)
  24. In a flower name the parts that make up;
    1. Gynoecium (1mk)
    2. Androecium (1mk)
  25. State two sites for gaseous exchange in submerged aquatic plants. (2mks)
  26. Viability of a seed is a necessary internal condition for germination. State two factors that may lead to low viability. (2mks)
  27. Name two disorders in human caused by chromosomal mutation. (2mks)
  28. State two characteristics that researchers select in breeding programme. (2mks)
  29. A man and his wife are able to roll their tongues but their children cannot. Rolling tongue is controlled by a dominate gene. What are the genotypes of the parents. (Use letter T to represent the gene for tongue rolling) (2mks)
    1. State the economic importance of the following plants excretory products.
      1. Papain (1mk)
      2. Colchicine (1mk)
      3. Tannin (1mk)
    2. State two advantages of homiotherms over poikilotherms. (2mks)

Marking Scheme

    1. (2 mks)
      • Have mammary glands;
      • Have external ears /pinna;
      • Body covered with fur /hairs;
    2. Genus; (1 mk)
    1. Myofibril; rej myofibrils (1 mk)
      Tendon  Ligament 
      Connective tissue that joins bones to muscles  Connective tissue that joins bones to bones; 
      (1 mk) mark as a whole
  3. (2 mks) mark the first two
    • Prevent dirt /dust from getting into the specimen;
    • Remove air bubbles;
    • Hold specimen into place;
    • Protect objective lens from staining;
    • Turning / manipulation of grass during cutting by teeth; (1 mk)
    • Piercing / tearing / griping;
      • Autotrophic nutrition; (1 mk)
      • Limited movement; (1 mk)
      • Growth occurs at specific regions; (1 mk)
      • Cytology; (1 mk)
      • Microbiology; (1 mk)
    1. Passage of ova, site for fertilization; (1 mk) any one correct
    2. Temporary storage of sperms; (1 mk)
    3. Hold / support testes / protection of testis; (1 mk)
    1. Animals use carbohydrates for respiration when they are amply supplied with food; (1 mk)
    2. Animals use fats for respiration when the carbohydrates reserves are exhausted; (1 mk)
    3. Animals use tissue proteins during starvation, when the carbohydrates and fat are exhausted (1 mks)
  8. Convergent evolution occurs when organisms with different ancestral origin develop analogous structures.
    Divergent evolution occurs when organisms with common ancestral origin adapt along different lines; (1 mk) mark as a whole
    • Lack of food / algae;
    • Presence of predators;
    • Presence of disease causing microorganism;
    • Insufficient oxygen in water;
      Mark the first three (3 mks)
      1. Objective lens – contributes to the magnification of image and brings it to the focus (1 mk)
      2. Fine adjustment knob – move the body tube through smaller distances to bring the
         Image into sharp focus (1 mk)
    2. Length of one cell = diameter of field of view ;
                                         number of cells
      = 6000/66 = 90.9 µm; (2 mk)
  11. (3 mks)
    1. Iris of the eye;
    2. Cilliary body;
    3. Erecto pili muscle;
    1. Melanin – screen against ultra violet rays from the sun; (1 mk)
    2. Sebum – Keeps the hair and epidermis supple and waterproof; (1 mk)
      Contains antiseptic substances for protection against micro organisms;
    3. Adipose fat deposit – storage of energy;
    1. Enables in water conservation in tissues of plants;
    2. Reduce water loss by evaporation and transpiration;
    3. Humid air accumulates in the cavities this reduces diffusion gradient between the inside of the leaf and immediate environment and thus reducing the rate of transpiration;
    1. carbon IV oxide + Ethanol + Energy; (1 mk)
    2. Lactic acid + Energy; (1 mk)
  15. Lamarck’s theory of evolution is not accepted because evidence does not support Lamarck’s theory of use and disuse; acquired characteristics are not inherited; characteristics are found in somatic cells only; (2 mks)
  16. Animals have complex excretory products as compared to plants that have simple excretory
    Products; animals have more metabolic activities hence their wastes accumulate to toxic levels requiring specialised organs for its elimination; (2mks)
    1. Thigmotropism / Haptotropism; Rej. Thigmotrophism or haptotrophism (1 mk)
    2. Part of the tendril in contact with support causes migration of Auxin to opposite; side leading to Faster cell division /growth on one side not in contact with the support; this causes the tendril To curl /coil /curve around the support; (3 mks)
    1. A condition in which the rate of water loss is more than the rate of absorption and plant droops; (1 mk)
    2. Rate of active transport increases with increase in temperature up to optimum temperatures;
      Faster increase in temperature slows down the rate of active transport; (2 mks)
  19. (4 mks)
    • Have thin epithelium to reduce distance over which gases diffuse;
    • Have large surface area for rapid diffusion of gases;
    • Highly vascularised to transport the diffusing gases;
    • Have a moist surface to dissolve the respiratory gases;
    1. adult and larvae exploits different food niches thus do not compete for food; pupa can survive adverse conditions since its dormant /encysted / non feeding stage; (2 mks)
    2. Primary growth is the increase in length /height of a plant due to cell division and elongation of Apical meristem while secondary growth is the increase in width / girth of a plant stem and root due to cell division and elongation of vascular and cork cambium ; ; (2 mks)
    1. X- Carbon IV oxide; (2 mks)
      Y- Oxygen;
    2. 19.0-10.6 =8.4 cm3 ;; (2 mks)
    1. Stigma, Style, Ovary; (1 mk) (All parts must be present in order to score)
    2. Anther & Filament; (1 mk)
  23. Aerenchyma; (1 mk)
    Epidermis; (1 mk)
  24. Seeds stored for too long due to depletion of food reserves;
    Destruction of embryo by pests;
  25. (3 mks) mark the first two
    • Downs syndrome;
    • Turners syndrome;
    • Klinefellers syndrome;
  26. Epicotyl;
    • Disease resistance;
    • Early maturity;
    • High yields; (2 mks)
  28. Dry mass gives the actual amount of living matter in an organism; while fresh mass is dependent Of the amount of water present in an organism; (2 mks)
  29. Mother -Tt; (1 mk)
    Father -Tt; (1 mk)
    1. Papain – Used in food industry as meat tenderizer; (1 mk)
      Colchicine – Used to induce polyploidy and in cancer therapy; (1 mk)
      Tannin – Used for tanning hides and skin in manufacture of leather; (1 mk)
    2. Remain active throughout the day;
      Can exploit a wide range of ecosystem; (2 mks)

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