BIOLOGY PAPER 1 - KCSE 2019 STAREHE PRE MOCK EXAMINATION (WITH MARKING SCHEME)

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  1. Identify the structure of the cell that performs the following functions
    1. Synthesis of ribosome (1mk)
    2. Regulate exchange of substances in and out of the nucleus (1mk)
    3. Formation of spindle fibres (1mk)
  2. State the importance of the following processes
    1. Ultra-filtration (1mk)
    2. Selective reabsorption (1mk)
  3. The diagram below represents an organism.
    BIO3YAT
    1. In which kingdom does the organism belong (1mk)
    2. Give a reason for your answer (1mk)
    3. Name the structure labeled A (1mk)
  1. What difference would you expect to see between pea seedlings grown for ten days in total darkness and pea seedlings grown in light for the same period of time (3mks)
  2. A form one student trying to estimate the size of onion cells observed the following on the microscope’s field of view
    BIO5YAT
    1. Define the term resolving power             (1mk)
    2. If the student counted 20cells across the field of view, calculate the size of one cell in micrometers       (2mks)
  1. During a strenuous exercise, the chemical process represented by the equation below takes place in human muscles
    C6H12O6  → 2CH3CH(OH)COOH + 150KJ
    (Glucose)       (Substance X)        (Energy)
    1. What is the name of this process                         (1mk)
    2. Name the substance X                         (1mk)
    3. Explain what happens in the body when substance X accumulates in the muscle in high amounts(1mk)
  1. State the effect of damping untreated sewage into a river (3mks)
  2.  
    1. What is meant by double fertilization in plants (2mks)
    2. Mention two development stages that take place in the ovary of a flower after fertilization. (2mks)
  1. What is meant by the following terms
    1. Hybrid vigour (1mk)
    2. Polyploidy (1mk)
  2. Name the causative agent of the following human diseases
    1. Malaria (1mk)
    2. Typhoid (1mk)
  3. The graph below shows relationship between two species a and B. species B is a predator feeding on species A
    BIO11YAT
    1. When the predators are too efficient, what happens to both populations? (1mk)
    2. If predators were entirely removed, what might happen to the prey population?             (3mks)
  4. Define the following terms
    1. Test cross (1mk)
    2. Phenotype (1mk)
    3. Dominant gene (1mk)
  1. State two functions of cell sap (2mks)
  2. State the name given to the study of:
    1. Structure of tissues (1mk)
    2. Study of fishes     (1mk)
    3. Development of animals from egg to adult (1mk)
  3. Give reasons for carrying out the following procedures when preparing temporary wet mounts of plant tissues.
    1. Making thin plant sections (1mk)
    2. Adding water on plant section (1mk)
    3. Placing a cover slip over the plant sections (1mk)
  4.  
    1. What is diffusion? (2mks)
    2. How do the following factors affect the rate of diffusion?
      1. Diffusion gradient (1mk)
      2. Surface area to volume ratio (1mk)
      3. Temperature          (1mk)
  1. The table below shows the concentration of sodium and iodine in sea water and cell sap of a plant.
     

    Sodium ion concentration

    Iodide concentration

    Sea water

    250

    35

    Cell sap

    100

    550


    If the plant was sprayed with a chemical that inhibit respiration:
    1. Which of the two ions uptake will be affected (1mk)
    2. Give a reason for your answer in (i) above (1mk)
  1. What is the role of vascular bundles (3mks)
  2. Describe what happens during light stage photosynthesis (3mks)
  3. What happens to the end products of photosynthesis (4mks)
  4.  
    1. Name one appropriate food substance for each of the following enzymes
      1. Ptyalin (1mk)
      2. Pepsin (1mk)
    2. State two symptoms of Beri-Beri       (2mks)
  1. How is the human stomach adapted to
    1. Protein digestion (3mks)
    2. Churning (1mk)
  1. the diagram below represents the region of a root tip
    BIO23YAT
    1. Name the three regions above X in ascending order (3mks)
    2. State the function of the part labeled X (1mk)
  2.  
    1. Name the antigens that determine human blood group      (2mks)
    2. Explain three protective role of mammalian blood         (3mks)
  1. How are mitochondria adapted to their functions (2mks)
  2. State two ways in which anaerobic respiration is applied in industries (2mks)


MARKING SCHEME

  1.  
    1. Nucleolus;
    2. Nuclear membrane/pore;
    3. Centriole
  2.  
    1. To remove toxic/ harmful substances/ urea/ nitrogenous waste from the blood stream; Rej: excess water and mineral salts;
    2. To return useful substances/ glucose and amino acids back into the blood stream;
  3.  
    1. Protoctista
      Unicellular with membrane bound nucleus acc presence of flagellum/contractile vacuole
    2. Flagellum;
  1.  
    1. Ability to distinguish two very close parts as separate entities;
    2.  
      BIO1YAT 
  2.  
    1. Anaerobic respiration;
    2. Lactic acid;
    3. Deep breathing to increase oxygen supply to the muscle/ tissue so as to break lactic acid to carbon (IV) oxide and water;
  3.  
    • Poisonous chemical in the sewage will kill aquatic organisms;
    • Nutrients/ mineral ions in the sewage cause growth of water plants/ eutrophication;
    • Sewage make water unclean/unsuitable for human consumption;
    • Pathogens in water may cause diseases;
    • Saprophytic bacteria and fungi depletes dissolved oxygen in water leading to suffocation and death;
  1.  
    1. Fertilization in which one male nucleus of a pollen grain fuses with egg cell nucleus to form a diploid zygote; and another male nucleus fuse with polar nuclei to form a triploid primary endosperm;
    2. -Ovary -becomes a fruit;
      -Ovules- become seeds;
  2.  
    1. Production of plants and animals that have a greater productivity/ have beneficial characteristics than either of the parents;
    2. Condition where an individual has more than two sets of chromosomes;
  3. Name the causative agent of the following human diseases
    1. Malaria-----------Plasmodium malariae;
    2. Typhoid----------Salmonella typhi;
  4.  
    1. Both population will decline;
    2. Increase in A leads to increase in B ;then decrease due to competition for food;
  5.  
    • A cross with homozygous recessive done to determine the genotypes of an organism;
    • Outward appearance of an organism;
    • One that express itself in both homozygous and heterozygous state;
  6.  
    • Stores dissolved chemicals like salt and sugar;/creating osmotic pressure
    • Maintaining the shape of a cell;(osmotic brings about movement of water into and out of the cell by osmosis;
  1.  
    1. Histology;
    2. Ichthyology;
    3. Embryology;
  2.  
    1. To reduce layers of cells hence allow light to pass through;
    2. To make the cells turgid or prevent drying up hence maintain the shape;
    3. To protect lens on objective lens; exclude air/ dust/ foreign particles, hold the specimen in position;
  1.  
    1. Diffusion is the movement of molecules from a region of high concentration to a region of low concentration; N/B( must score as a whole)
    2.  
      • The higher the diffusion gradient, the higher the rate of diffusion while the lower the diffusion gradient the lower the rate of diffusion
      • The higher the surface area to volume ratio the faster the rate of diffusion while the lower the ratio the slower the rate of diffusion
      • Increasing temperature increases the energy content in a molecule hence faster rate of diffusion;
  2.  
    • Iodide ions;
    • Iodide ions are taken up by active transport i.e. against concentration gradient and this process requires energy delivered from respiration i.e. sea water has lower concentration of iodide ions;
  1. Xylem conducts water from the roots to the leaves; phloem tissue translocates manufactured food soluble and organic products of photosynthesis from leaves to the growing regions/ rest of the plant parts; xylem has lignin that acts as a straightening tissue;
  2. Light stage photosynthesis is light dependent; it takes place in the grana of the chloroplast. Light is trapped and used to split water molecules into hydrogen ions and oxygen atoms(photolysis) energy is formed and is stored in form of ATP / Adenosine Triphosphate;
  3.  
    • Oxygen-used in respiration;(some is released to the atmosphere)
    • Glucose-used in respiration; some is converted to sucrose or starch for storage; it is used in formation of structures in plants such as cellulose cell wall/ cytoplasm;
    • Amino acids- used for growth and development ;(formation of various structures)
      N/B one must specify the end product to score
  4.  
    1.  
      • Starch;
      • Proteins;
    2. Retard growth; swelling of legs; wasting muscles; general body weakness; paralysis of legs, arms, gastro-intestinal disturbance, pale skin;
  5.  
    1. Has gastric gland which produces pepsin enzymes that digest proteins to peptides, also rennin that curds milk;
      -Gastric juice contains hydrochloric acid that provides acidic medium for maximum pepsin enzyme activity to digest proteins;
      -Has goblet cells that secret mucus to like the stomach wall against protein digesting enzymes and corrosion by hydrochloric acid;
    2. Has smooth muscle that contain fluck circular and longitudinal layers which contracts and relax producing movements that mix contents of the stomach;
  1.  
    1. Zone of cell division; zone of cell elongation; zone of cell enlargement;
    2. To protect apical meristem;
  2.  
    1. Antigen A;   Antigen B      N/B (must be in capital letters)
    2.  
      1. Contains platelets whose role is blood clotting when vessels are injured to prevent entry of micro-organisms and excessive loss of blood;
      2. Contain lymphocytes that produce antibodies that protect the body from infections;
      3. Contain phagocytes that engulf and digest pathogens through phagocytosis;
  3.  
    • Inner membrane is highly folded to form cristae which increases the surface area for the attachment of the respiratory enzymes;
    • Presence of respiratory enzymes to catalyse the rate of reaction;
  4.  
    • Baking e.g. bread;
    • Brewing e.g. beer, wine;
    • Formation of dairy products of cheese;
    • Formation of organic acids e.g. oxalic acid, vinegar (ethanoic acid), vinegar etc 

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