KCSE 2015 Biology Paper 1 with Marking Scheme

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Answer all the questions in the spaces provided.

    1. What is meant by the term binomial nomenclature? (1 mark)
    2. state two guidelines that should be followed when typing scientific names. (2 marks)
  2. During a lesson, students observed the structures of bat, cat and human forelimbs to determine their evolutionary relationship.
    1. State the name given to the structure of the limbs observed by the students. (1 mark)
    2. Name the type of evolution illustrated by the structure of the limbs observed. (1 mark)
    3. What evidence of evolution is illustrated by limbs? (1 mark)
    4. State the significance of the type of evolution illustrated by the limbs. (1 mark)
  3. An individual is of blood group B positive.
    1. Name the antigens in the individual’s blood. (2 marks)
    2. Give the reason why the individual cannot receive blood from a blood group A donor. (2 marks)
  4. Colour blindness is a sex linked trait controlled by recessive gene b. If a mother is a carrier and the father is normal, what is the chance that their son will be colour blind? Show your working. (4 marks)
    1. State two advantages of using a coverslip when preparing a specimen for observation under a light microscope. (2 marks)
    2. How is the low power objectives lens manipulated to focus a specimen for observation under a light microscope (2 marks)
  6. Students set up an experiment as illustrated below.
    osmosis experiment kcse 2015
    1. Name the physiological process that resulted in the observation made after 30 minutes  (1 mark)
    2. State the importance of the physicaological process investigated in plants. (1 mark)
    3. Explain the observation made after 30 minutes. (2 marks)
  7. How is a guard cell structurally adapted for gaseous exchange? (4 marks)
    1. Name the organism that:
      1. Causes malaria;  (1 mark)
      2. Transmits malaria. (1 mark)
    2. State two control measures for malaria. (2 marks)
  9. The diagram below shows an experiment set up to investigate a certain physiological process in plants.breathing in plants kcse 2015
    1. State the aim of the experiment. (1 mark)
    2. State the role of the following in the experiment:
      1. potassium hydroxide; (1 mark)
      2. aluminium foil (1 mark)
    3. Accounts for the expected colour change in tube F.
  10. The diagram below illustrate the skull of adult human and chimpanzee.Human and chimpanzee skull kcse 2015
    1. State one difference between the two skull in the following structures: (3 marks)
        Structure Chimpanzee Skull Human Skull
      (i) Parietal bones    
      (ii) Mandible    
      (iii) Browridge    
    2. State the significance of the evolution observed on the parietal bone in the chimpanzee and human. (1 mark)
  11. Name two structures used for gaseous exchange in plants. (2 marks
    1. What is meant by each of the following:
      1. pyramid of numbers?  (1 mark)
      2. pyramid of biomass? (1 mark)
    2. During an ecological visit to the Savanna Grassland, students were able to see lions, antelopes, vultures and pastoralists grazing their cattle. Construct a food chain with consumer levels to illustrate the energy flow in the ecosystem. (2 marks)
  13. State three differences between the end products of mitosis and meiosis.
    Mitosis                                                                                        Meiosis
    1. Name two types of involuntary muscles in mammals. (2 marks)
    2. state the location of each of the muscles named in (a) above. (2 marks)
  15. The photomicrograph below shows the various stages of cell division in a certain plant.
      1. Name the type of cell division illustrated. (1 mark)
      2. Give a reason for your answer in (a)(i) above. (1 mark)
      1. Name the stage cell division labelled K. (1 mark)
      2. Give a reason for your answer in (b)(i) above. (1 mark)
  16. State four structural differences between millipedes and centipedes. (4 marks)
    Millipedes                                                                           Centipedes
    1. How is a human stomach adapted to
      1. protein digestion? (2 marks)
      2. churning? (2 marks)
    2. What happens to the glucose synthesized during photosynthesis? (2 marks)
    1. The diagram below shows an experimental set-up to investigate the conditions necessary for germination.Test tube P was placed in a refrigerator while Q was left at room temperature. The set-ups were observed regularly for two weeks but no germination occurred.Cell division KCSE 2015
    2. Explain the observations in P and Q. (2 marks)
    1. Using the axes provided below, sketch a curve to illustrate the growth pattern observed in the phylum arthropoda. (2 marks)
    2. Explain the growth pattern observed observed in arthropods.
  20. Below are components of a simple reflex pathway
    • intercourse
    • muscles
    • motor neurone
    • sensory neurone
    • pain receptor
    • central nervous system
      List the components in their proper sequences during the transmission of a nerve impulse. (3 marks)


    1. The scientific system of giving two names (Genus and species) to living organisms; (1 mark)
    2. The Genus name starts with a capital letter while the species name starts with a small letter; The two names are typed in italics/two names underlined separately; (2 marks)
    1. The pentadactyl limb/homologous structures; (1 mark)
    2. Divergent evolution/adaptive radiation; (1 mark)
    3. Comparative anatomy; (1 mark)
    4. It allows the organisms to exploit different habitats to reduce competition; (1 mark)
    1. (Antigen) B;
      Rhesus (antigen)/Rheus factor/Antigen D
    2. Has antibody a in the blood plasma of the recipient and will correspond with antigen A in the donor's blood, hence there will be antigen antibody reaction/agglutination.   

  4. 1
    Punnet square
    Parental genotypes   XBXb    x    XBY
    XB   XBXB XB Y
    Xb  XBXb   XbY
      1. To hold the specimen in place;
      2. Protects specimen from dehydration/drying up/dust particles;
        Protect objective lens from staining. (2 marks)
    2. Click the low power objective lens into position. Bring it down to the lowest level using the coarse adjustment knob; With eyes on the eyepiece lenses and using the coarse adjustment knob gradually raise/ lower the low power objective lens to bring the specimen into focus; (2 marks)
    1. Osmosis; (1 mark)
    2. Absorption of water from the soil; opening and closing of stoma; feeding in insectivorous plants; support (in seedlings, leaves,herbaceous plants); Movement of water from cell to cell in plants. Any correct 1 (1 mark)
    3. The thistle funnel gained water by osmosis; because the sucrose solution was hypertonic; (2 marks)
    • Thin/elastic outer wall; it bulges outwards;
    • Thick/less elastic inner wall; it curves to open the stomata/straightens to close the stomata;
    • Has chloroplasts; for photosynthesis/synthesizedd sugar (glucose/sucrose/fructose) that is osmotically active.(4 marks)
      1. Plasmodium spp/malariae, vivax, Ovale, falseparum;
      2. Anopheles female mosquito; (2 marks)
      • Controlling mosquitoes/vectors/cleaning breeding sites/draining stagnant water/use of insecticides;
      • Vaccination/taking prophylactic drugs;
      • Sleeping under mosquito nets / use of mosquito repellants. Any two correct (owtte)(2 marks)
    1. To show that carbon (IV) oxide is produced during respiration in plants;
      1. Absorb carbon (IV) oxide from the incoming) air;
      2. Exclude light / to prevent photosynthesis;(1 mark)
    3. No colour change in tube F / no observable colour change. Carbon (IV) oxide removed/absorbed from air by potassium hydroxide. (2 marks)

    1. Structure Chimpanzee Skull Human Skull
      Parietal bones  - less curved/flatter
      - towards the back
      - smaller
      - more curved
       - more central Any correct
      - larger 1 mark
      Mandibles larger  smaller 1 mark
      Browridge   - thicker /more protruding
      - conspicuous/prominent 
      - less protruded 1 mark 
      - less conspicuous/prominent
    2. Accommodate large sized brain in humans; (1 mark)
    • Stomata (in leaves);
    • Lenticels (in stems and roots)/pneumatophores;
    • Epidermis (roots)
    • Cuticle
      1. Pyramid of biomas represents total dry mass weight of organisms in each trophic level;
      2. While pyramid of numbers represents the total number of organisms at each trophic level/feeding levels/nutrition levels; (2 marks)
    2. Appropriate examples for;
      Grass (Vegetation)        Cattle(antelope)            Man(pastoralist)                  Lion                           Vulture
      Producer             →   Primary consumer  →   Secondary consumer → Tertiary consumer  → Quartiranery consumer (2 marks)

  13. Mitosis Meiosis 
    two daughter cells
    - Daughter cells diploid
    - Identical to mother cell/no variation 
    - Four daughter cells
    - Daughter cells haploid/are gametes
    - Results in variation 
    (3 marks)
    1. Smooth muscles/visceral muscles;
      Cardiac muscles;
    2. Smooth muscles - tubular visceral organs; (1 mark)
      Cardiac muscles - heart (1 mark)
      1. Mitosis;
      2. Formation of two daughter cells.(2 marks)
      1. Metaphase;
      2. Chromosomes are at the equator. (2 marks)
  16. Millipedes
    • Cylindrical body
    • Each segment has two pairs of walking
    • legs (except the first thoracic segment)
    • Head has two clumps of many simple eyes
    • Head has a pair of long antennae
    • No poison claws
    • Three body parts - head short, throrax, and trunk
    • Has anterior genital aperture
    • Has 9 - 100 segments

    • Dorso - ventrally flattened
    • Head has a pair of simple eyes
    • Each segment has a pair of waking legs
    • Head has a pair of short antennae;
    • Has poison claws 
    • Two body parts - head and trunk  
    • Has aposterior genital aperture 
    • Has 15 - 21 segments (4 marks)
      1. Has gastric glands; that secrete gastric juice; (2 marks)
      2. Thick muscular wall; that contract and relax;
        Accept a component of gastric juice (pepsin, Rennin, mucus, hydrochloric acid). (2 marks)
      • Used in plant respiration to produce energy;
      • Converted to starch/sucrose/lipids/proteins/cellulose and stored; for future use. (2 marks)
  18. P- the low temperature/freezing temperature; inactivated enzymes; (2 marks)
    Q- Boiling eliminated oxygen; oil layer prevented entry of oxygen necessary for respiration during growth; (3 marks)

    1. 2
    2. Intermittent growth is as a result of the shedding of the exoskeleton/moulting/ecdysis. The growth rate slows down (flattening) as the exoskeleton hardens; after moulting, growth occurs rapidly (steep slope) until the exoskeleton hardens.
  20. Pain receptor -> Sensory neurone; Interneurone → CNS; Motor neurone → Muscle.
    OR Pain receptor sensory neurone; inter neurone → CNS → interneurone; motor neurone → Muscle.
    Pain receptor
    sensory neurone; CNS → interneurone; motor neurone → muscle
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