Biology Paper 1 Questions and Answers - Asumbi Girls Mock Examinations 2022

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QUESTIONS

  1. Study the diagram below showing a portion of an onion epidermis that had been irrigated with a certain solution X.
    1
    1. In one word describe the condition of the cells
    2. Describe the process that lead to the condition named above
  2. The following reaction may proceed in forward or backward direction
    Glucose + fructose ⇌ sucrose + water.
    1. What term is used to refer to the backward reaction
    2. In which part of alimentary canal does the backward reaction occur?
    3. Name the enzyme that catalyzes the backward reaction
  3. A certain metabolic pathway takes the following sequence.
    J → K → L → M → N
    At the start of the experiment an inhibitor was added to the reactants. After the experiment it was found out that there was the same concentration of J, more than normal concentration of K, near absence of L, M and N. When L was added to the inhibitor set M and N were detected.
    1. At what stage of the reaction sequence did the inhibitor have its effect?(1mk)
    2. Explain how the inhibitor affected the reaction.  (1mk) 
    3. What is the identity of substance L? (1mk)
  4. After fertilization of an ovule, which parts develops into: -
    1. Testa
    2. Endosperm
  5.      
    1. Explain two roles of diffusion in human beings.
    2.      
      1. Name the process through which a plant takes up some mineral ions against a concentration gradient
      2. State two factors that may affect the process named in b(i) above.  (2mks)
    3. Distinguish between haemolysis and plasmolysis. (1mk)
  6. An insect landed on a leaf of an insectivorous plant. Consequently, the leaf closed with its spines interlocking trapping the insect inside it. Name the response exhibited by the leaf. (1mk)
  7. The figure below represents a plant.
    2
    1. State the division it belongs to. (1mk)
    2. Label the parts labeled
    3. State the role of part labeled d in the life cycle of the organism
  8. State any two adaptations of the cardiac muscle that enable it to undergo systole. (2mks)
  9. A respiratory substrate has the formula C57H110O6.
    1. Write a balanced equation to represent its complete oxidation to carbon dioxide and water. (1mk) 
    2. Why are carbohydrates and not lipids the first choice respiratory substrates?  (2mks)
    3. Calculate the RQ from the equation in (a) above. (2mks)
  10. Below is a diagram of a group of cells of a specific tissue.
    3
    1. Name the tissue  (1mk)
    2. This tissue lines the trachea and bronchi. Suggest its function in these structures. (1mk)
  11. Study the flow chart below which represents a physiological process in mammals
    4
    1.      
      1. Name blood components represented by X. (1mk)
      2. What is the significance of product represented by Z. (2mks) 
    2. Under what condition is thrombokinase released by the platelets?   (1mk)
  12.      
    1. Explain what happens to excess amino acids in the liver of humans.  (3mks)
    2. Which portions of the human nephron are only found in the cortex? (1mks)
  13. A potted plant is transferred from outside on a sunny and windy day, to a dark room.
    Briefly explain the effect this is likely to have on:
    1. The rate of loss of water from its leaves (3mks)
    2. The rate of water absorption. (2mks)
  14. Give a reason why urine of a mammal does not contain amino acids. (1mks)
  15.    
    1. In what form is energy stored in muscles? (1mk)
    2. State the role of insulin in human body. (3mks)
  16. Name the processes that take place in the liver to bring about differences between blood in the Hepatic portal vein and that in the hepatic vein. (3mks) 
  17. The graph below shows how the body temperature of a toad and man varies with time in  hours. Study it and answer the questions that follow.
    5
    1. What is the relationship between the body temperature of the toad and that of the atmospheric air?(1mk)
    2. State two corrective measures that maintains man’s body temperature at norm even when the environmental temperature is below 30ºC.(2mks)
    3. Give one behavioral adaptation observed in a lizard when the environmental temperature is above 39ºC.   (1mk)
  18. The figure below shows the exposed breathing apparatus of a fish.
    6
    1. Name the structure that was removed to expose the apparatus. (1mk)
    2.       
      1. Name structure P. (1mk)
      2. State two structural adaptations of the respiratory surface in insects.  (2mks)
  19. The following is a reproductive structure of a plant.
    7
    1. Identify the structure. (1mk)
    2. Name the sub-division of the plants that produces the above reproductive structure. (1mk)
    3.        
      1. Name structure B.  (1mk)
      2. What is the function of structure A? (1mk)
  20. Nucleic acids are made up of nucleotides that bears a sugar component.
    1. Name the sugar component found in: -   (2mks)
      1. DNA fragment
      2. RNA fragment
    2. The following nucleotide sequence was found in a segment of DNA: -  A G C C T.
      Write down the complementary base sequence in the corresponding m RNA segment during transcription(1mk) 
    3. A point mutation altered the base sequence from the original to G G C C T.
      Identify the type of gene mutation.(1mk)
  21. Below is a drawing of a cell.    
    8
    1. With two reasons, identify the cell. (3mks)
      Identify.
      Reasons:
    2. Which of the three structure X, Y and Z speeds up transmission of the impulse. (1mk)
  22.         
    1. State two structural differences between skeletal muscles and smooth muscles. (4mks)
      Skeletal muscle Smooth muscle
         
    2. What are antagonistic muscles? (1mk)


MARKING SCHEME

  1.      
    1. Hypertonic;
    2. The cell sap was hypotonic to the solution X; hence water was drawn from the cell into the solution by osmosis; making the cytoplasm to shrink and cell membrane detach from the cell wall;
  2.    
    1. Hydrolysis;
    2. ileum;
    3. Sucrase;
  3.    
    1. At K/ between K and L
    2. The inhibitor blocked the active sites of enzymes; that converts K to L; hence accumulation of K and near absence of  L,M and N;
    3. Enzyme activator;
  4.    
    1. Integuments;
    2. Primary endosperm nucleus;
  5.    
    1.    
      • Absorption of digested food such as glucose and amino acids; into the blood stream;
      • Exchange of respiratory gasses ie oxygen and carbon(iv) oxide; between the alveolus and blood capillaries;
      • Excretion of nitrogenous wastes such as urea; from the blood capillaries into elimination site;
        Any two  
    2.       
      1. Active transport;
      2.    
        • Low oxygen concentration;
        • lowering temperature below optimum level;
        • Presence of enzyme inhibitors;
          ANY TWO
    3. Haemolysis- A process by which red blood cells take up water from a solution of lower solute solution by osmosis till they burst.  OWITTE
      Plasmolysis – A process by which plants cell loss water to a solution of higher solute 
      Concentration by osmosis and becomes flaccid; OWITTE           
  6. Thigmonasty / Haptonasty; Rej. positive thigmonasty.
  7.    
    1. Bryophyta;
    2. A - Seta;
      B - Capsule;
    3. Produces gametes whose fusion gives rise to the sporophyte generation/C;
  8.      
    1. Has a specialized region on the right atrium / pace maker known as sinoatrial node; 
      Rej SAN
    2. Has a specialized muscle region at the boundary between atria and ventricle called atrio-ventricle node that spreads the contractions.
    3. Muscle cells are interconnected to enable spreading of the wave of contractions;
      ANY TWO
  9.        
    1. 2C57H110O6 + 163O→ 114CO2 + 110H2O + Energy.
    2. They are easily transported.
      They require less oxygen for their oxidation.
    3. 104 CO2 ; = 0.669;
       163 O2
  10.      
    1. (Ciliated) epithelial tissue.
    2. It wafts mucus with trapped dust/solid particles.
  11.      
    1.    
      1. Platelets;
      2. Forms a clot that prevents excessive bleeding/prevents entry of pathogens;
    2. When platelets are exposed to air;/ When platelets clump together and adhere to the wall of damaged blood vessel;
  12.       
    1. Excess amino acids are deaminated in the liver; with formation of ammonia; which reacts with carbon oxide to form urea, an excretory waste material.
    2. bowman’s capsule;
      Proximal convoluted tubule;
      Distal convoluted tubule ;
      (All tied)
  13.    
    1. Rate of loss of water reduces; because temperatures lowers and windy conditions reduced; reducing rate of transpiration.
    2. Rate of water absorption reduces; because rate of transpiration / water loss reduces hence less water needs to be replaced;
  14. All amino acids are re-absorbed in the proximal convoluted tubule / kidney nephron;
  15.      
    1. Adenosine-triphosphate; Rej ATP
    2. Insulin increased permeability of kidney tubules; increasing water re-absorption; when the body fluid’s osmotic pressure is below normal.
  16.    
    1. Deamination.
    2. Blood sugar regulation.
    3. Respiration
    4. Detoxification
  17.    
    1. The toad’s temperature fluctuates with the fluctuations of atmospheric air temperature.
    2.         
      • Increased respiration to generate more heat.
      • Vasoconstriction thus less blood flowing to the skin reducing heat loss.
      • Contraction of erector pili muscles raising the hairs (to upright position) trapping a layer of air that insulates the body against heat loss.
      • Shivering to generate heat;
      • Reduced or no sweating reducing heat loss;
        (Any three)
    3. Moves to cooler place / move to shade;
  18.      
    1. Operculum;
    2.    
      1. Gill filament;
      2. Are always moist for gasses to dissolve and diffuse in solution;
        • They (tracheoles) are branched to increase surface area to serve every cell;
        • They have thin wall to reduce distance of diffusion of gasses;
          (ANY TWO)
  19.      
    1. Pollen grain;
    2. Angiospermaphyta / Angiospermae / Angiospermatophyta;
    3.       
      1. Generative nucleus;
      2. Directs the growth of pollen tube through the style towards the micropyle; 
  20.        
    1.        
      1. Deoxyribonucleic acid;
      2. Ribonucleic acid;
    2. U-C-G-G-A;
    3. Substitution;
  21.      
    1. Motor neurone; 
      Reasons –
      1. cell body is found at the end of the axon;
      2. It is multipolar / from the cell body projects several dendrones;
      3. Has effector dendrites that terminates at the effector muscle/ skeletal muscle;
        (ANY TWO)
  22.         

    1. Found lining the inner walls of tubular structure.Unstriated.Cells have one nucleus.​
      Skeletal muscle Smooth muscle

      Attached to the skeleton
      striated
      their cells / fibres are multinucleated

      Found lining the inner walls of tubular structure.
      Unstriated.
      Cells have one nucleus.
      (ANY TWO)
    2. Muscles that work as a pair ,when one contracts the other one relaxes to cause movement;

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