2017 WAEC BIOLOGY THEORY AND OBJ

1ai. Classification of living things consist of placing together in categories those living things that resembles each other.
1aii. Carolus Linnaeus
1aiii. It allows scientist identify organism easily
         It enables scientist to easily group organism.

      It enables scientist to properly name organism in a standardized system
1aiv.  Kingdom
          Phylum or Division
          Class
          Order
          Family
          Genius
          Species
1bi. Virus can reproduce when present in another living cell.
        It possess characteristics which can be transmitted from one generation to another
1bii. Virus cannot respire, excrete or respond to external stmuli
         When virus is extracted from a living cell it assumes a crystalline form
1ci. Rosette diseases
       Cassava mosaic diseases
1cii. Human immunodeficiency virus (HIV)
        Polio
2ai. All enzymes are proteineous in nature
       Enzyme speed up the rate of chemical reaction
       Each enzyme are specific in nature
       Enzyme do not lose their chemical composition at the end of a reaction.
2bi. Ptyalin
       Renin
       ptyalin - starch
       renin- protein
2biii. Starch- maltose, partial hydrolysis of maltose
         protein - peptones and polypeptide
         fat and oil- fatty acid and glycerol
2ci. Chlorophyll helps in photosynthesis
2cii. Nitrogen
       Magnesium
2ciii. magnesium- yellowing of leaf
        nitrogen- stunted growth
2d. Aim: To test for the presence of starch in leaf
     Method: Boil the leaf in water so as to kill the cells and burst the starch grain present. Dip the leaf in a test tube containing 70% alcohol to decolourize the leaf. After dip the decolourized leaf nto a beaker containing hot water. Finally place the leaf on a white tile and pour few drops of iodine solution on the leaf.
    Observation: It is seen that the leaf turns blue-black.

6a. Smell receptor are stimulated by chemicals and are sensitive to chemicals. Particles of volatile chemicals in the air dissolves in the mucus layer over the smell receptor n the nostril. The stimulation gives rise to nerve impulse which travel to the olfactory nerve to the olfactory lobe in the brain. The bran then interpret the smell.
6b. Shell- The hard shell protect the embryo.
      Membrane- The membrane gives protection to the egg.
      Airspace- The airspace is important for respiration of the embryo.
      Albumen- It helps to nourish the egg
      Yolk- It supply nutrient to the embryo
      Chalaza- It holds the yolk and the embryo in position.
6ci. Autotrophs are organism that have the ability to manufacture their own food using carbondioxide and water in the presence of sunlight.
6d.  Function of WHO
     i It coordinate research programs in all field of health
     ii It provide advice on health matter
    iii It publish medical journals
     iv It provide drugs and vaccines in cases of emergencies
      v It helps in maternal and child health care.

WAEC BIOLOGY 2017 THEORY AND OBJ ANSWERS
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