KCSE 2010 Biology Paper 1 Questions with Marking Scheme

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  1. State the name given to the study of:
    1. The cell (1 mark)
    2. Micro-organisms (1 mark)

  2. The diagram below shows a transverse section of a plant organ.

    transverse section of plant organ kcse 10

    1. Name the plant organ from which the section was obtained. (1 mark)

      1. Name the class to which the section was obtained. (1 mark)
      2. Give a reason for your answer in (b)(i) above. (1 mark)

    2. Name the part labeled X. (1 mark)

  3. Name the functions of:
    1. Ribosomes; (1 mark)
    2. Lysosomes. (1 mark)

  4. The diagram below shows a specialized plant cell.

    specialized plant cell kcse 10

      1. Name the cell. (1 mark)
      2. Name the parts labeled D and E. (2 marks)

    1. State the function of the part labeled C. (1 mark)

  5. State three ways in which a respiratory surface is adapted to its function. (3 marks)

  6. State one function of the following:
    1. Cerebellum; (1 mark)
    2. Medulla oblongata (1 mark)

  7. Distinguish between haemolysis and plasmolysis. (2 marks)

  8. State three external differences between chilopoda and diplopoda. (3 marks)

  9. State two ways in which chloroplasts are adapted to their function. (2 marks)

  10. State two advantages of hybrid vigour, (2 marks)

  11. The diagram below shows a transverse section of a leaf.

    transeverse section of leaf kcse 11

    1. Name the habitat of the plant to which the leaf was obtained. (1 mark)

    2. Give two reasons for your answer in (a) above. (2 marks)

  12. The diagram below illustrates the structure of a bread mould.

    bread mould kcse 10

    1. Name the part labeled J. (1 mark)

    2. State the functions of the structure labeled K. (2 marks)

  13. What is meant by the following terms?
    1. Habitat; (1 mark)
    2. Ecosystem. (1 mark)

  14. Explain why it is not advisable to be in a poorly ventilated room with a burning charcoal stove. (3 marks)

  15. A potted plant was kept in the dark for 48 hours. Two leaves X and Y were treated as shown in the diagram below.

    transpiration kcse 10

    The experimental set-up was kept in sunlight for 6 hours after which a starch test was carried out on the two leaves.

    1. What were the results of the starch on the leaves X and Y? (2 marks)

    2. Give a reason for your answers in (a) above. (2 marks)

  16. What is the role of bile salts in digestion in humans? (2 marks)

  17. The following is the dental formula of a certain mammal:

    dental formular kcse 10

    1. State the likely mode of feeding of the mammal. (1 mark)

    2. Give a reason for your answer in (a) above. (2 marks)

  18. Give two reasons why animals have specialized organs for excretion as compared to plants. (2 marks)

  19. State the changes that occur in the arterioles in the human skin during thermoregulation. (2 marks)

  20. State two advantages of internal fertilization in humans. (2 marks)

  21. The diagram below represents part of the human skeleton.

    human skeleton kcse 10

    1. Name the part labeled P. (1 mark)

      1. Name the bone that articulates with the part labeled Q. (1 mark)
      2. What type of joint is formed between the parts labeled Q on the bone named in (b) (i) above? (1 mark)

  22. What is the function of the following structures in the human reproductive organs?
    1. Fallopian tubes; (1 mark)
    2. Epididymis; (1 mark)
    3. Scrotal sac. (1 mark)

  23. Explain three ways in which the red blood cells are adapted to their function. (3 marks)

    1. State two ideas proposed by Lamark in his theory of evolution. (2 marks)
    2. Why is Lamark’s theory not acceptable? (1 mark)

  24. State three factors that contribute to the deceleration phase in the population curve of an organism. (3 marks)

  25. State one survival value for each of the following plants:
    1. Thigmotropism in stems; (1 mark)
    2. Geotropism in roots; (1 mark)

    1. What is meant by the term non-disjunction? (1 mark)
    2. Give the example of a genetic disorder caused by:
      1. non-disjunction (1 mark)
      2. gene mutation (1 mark)

  26. State three structural differences between arteries and veins. (3 marks)

  27. The diagram below represents a female cone.

    female cone kcse 10

    1. Name the sub-division of the plant from which the cone was obtained. (1 mark)

    2. Other than the presence of cones, name two other external features that identify plants in the subdivision named in (a) above. (2 marks)

  28. What is meant by the term apical dominance? (3 marks)

Marking Sheme

    1. Cytology: Rej cell biology
    2. Microbiology
    1. Stem
      1. Monocotyledonae
      2. Vascular bundles scattered not arranged in a ring;
        Absence of pith; Absence of vascular cambium.
    3. Epidermis
    1. Protein synthesis (Accept: site for protein symbiosis)
    2. Destroys worn out organelles/cells/tissues
      Destroys micro-organisms.
      1. Root hair(cell)
      2. D – cell wall
        E – cell sap (vacuole)
    2. Controls the functioning of the cell/ controls cell activities
    • A large surface area for efficient diffusion of gases
    • Moist for gases to diffuse in solution form/to dissolve gases
    • Thin for efficient/diffusion of gases (across a short distance)
    • Most be close to body cells/well supplied with blood vessel to active cells
    • Ventilation mechanism for bringing in air rich in O2 and expelling air rich in carbon(iv) oxide
    1. Maintain balance/posture/control/muscular movement
    2. Control heart beat/ blood pressure/ breathing(rate) control involuntary activities/ response
      Accp. Curved examples of v.a e.g. eating, swallowing e.t.c.
  7. Haemolysis – process by which red blood cells take in water till they burst; while
    Plasmolysis – loss of water from plant cells until the cell membrane is detached from the cell wall/ until the cell become flaccid.
    Chilopoda  Diplopoda

    - A pair of (walking)legs per segment
    - Body flattened dosoventrally
    - Body divided into head and trunk Acc. Body divided into two body parts
    - Posterior genital aperture
    - Has poisonous claws
    - Have long antennae

    - 2 pairs of(walking)legs per segment
    - Body cylindrical in shape
    - Body divided into head thorax and trunk Acc body divided into three body parts
    - Anterior genital aperture
    - Lacks poisonous claws
    - Have short antennae.
    • They contain chlorophyll which traps/absorb light (energy)
    • They have grana which increase surface area for accommodation of a large number of chlorophyll molecules for photosynthesis
    • The stoma has enzymes for photosynthesis
    • Resistance to diseases/pests/adverse weather conditions (Acc. Correct examples e.g. drought, very high/ low temperatures
    • Increased yields
    • Earlier maturity Acc. Early maturity
    1. Aquatic / fresh water
      • Large air space/aerenchyma
      • Sclereids
      • Stomata on upper epidermis/absence of stomata in lower epidermis
      • Absence of cuticles
      • Poorly developed vascular bundles
    1. J – sporangium
      • Absorption of soluble substances/ digested food
      • Secretion of digestive enzymes;
      • Anchorage(of mould on substrate); anchorage must be in the right context
    1. Place/environment in which (specified)organism lives
    2. A natural unit with abiotic and biotic factors
  14. Charcoal in limited supply of air produces carbon(ii)oxide; which combines with haemoglobin forming carboxyhaemoglobin; which is stable/ does not dissolve reducing capacity of the haemoglobin leading to suffocation/ death;
    1. X – Starch present
      Y – Starch absent
    2. X – acts as a control; Y – CO2 absent absorbed by potassium hydroxide pellets; Acc correct explanation
  16. Emulsification / breaking down of fats into (tiny) droplets
    Creating alkaline medium for digestive enzymes/ neutralizing acidic chyone (from the stomach)
    1. Herbivorous; Rej Harbivores
    2. Lack canines/ incisors on upper jaws
  18. Animal form waste products more rapidly than plants/ Produce more metabolic wastes
    Animals don’t reuse their waste while plans reuse some of their wastes;
  19. When temperature is high they dilate; when low they constrict (Acc. Vasodilatation)
    • Higher chances of fertilization
    • Embryo/gamete is protected from external environment conditions
    1. P – sutures
      1. Atlas;
      2. Hinge joint
    1. Passage of ova/ site of fertilization
    2. Storage of sperms
    3. Hold the testis/ protect the testis
    • Absence of nucleus, increase of space for packaging haemoglobin(for carrying oxygen)
    • Possession of haemoglobin which has high affinity for oxygen
    • Bi-concave shape creates large surface area for combining with oxygen
    • Ability to change shape/flexible to enable them pass through capillaries.
    • Have carbonic anhydrate which increase CO2 transportation
    • Are numerous/many to be able to carry max amount of oxygen
    • Has plasma membrane which allow rapid diffusion of gases
      • Use and disuse
      • Acquired traits can be passed on to offspring
      • Acquired characteristics cannot be inherited
      • No evidence to support the theory
    • Overcrowding
    • Accumulation of toxic wastes
    • Limited resources such as nutrients
    1. Provide support
      Enables plants to grow forward light
    2. In search of nutrients
    1. Failure of homologous chromosomes to segregate during meiosis/ anaphase I/ meiosis I
      Failure of sister chromatid to segregate during meiosis/ anaphase II / meiosis II.
      1. Down’s syndrome; Turner’s syndrome; Klinefelter’s syndrome
        Surnerz syndrome
        Acc. Mongolism for Doran’s syndrome
      2. Albinism; single cell anaemia; heamophilia; colour blindness
        Chondrodytrophic dwarfism/ Achondroplasia
    • Arteries have thick muscular walls; veins have thin and less muscular walls
    • Arteries have narrow lumen, veins have wider lumen
    • Arteries have no valves except at junction with heart; veins have valves at regular intervals.
    1. Gymnospermae/ Gymuspermatophyta/ Gymnosperonaphyta;
    2. Needle-like leaves; thick waxy cuticle
      Naked seeds; sunken stomata.
  30. The inhibition of growth of lateral buds; by auxins; produced by the growing apical bud.
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