Biology Paper 1 Questions and Answers - KCSE 2022 Mock Exams Set 1

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INSTRUCTIONS

  1. All Questions are Compulsory
  2. Write your Answers in the Spaces Provided
  3. Wrong Spelling of Technical Terms shall be Penalized

Max Score

Student’s Score

80

 

QUESTIONS

  1. The diagram shown below represents a nuscleus
    1 zfsdfaa
    1. State the role of the organelle labelled Q (1mk
    2. Name a Kingdom whose members lack structure labelled P (1mk
    3. Which is the general term given to organisms whose cells have structure P? (1mk
  2.                      
    1. Name the TWO components of a lipid molecule (1mk
    2. State TWO disadvantages of using fats as respiratory substrates (2mks
  3.                    
    1. Name the pigment that protects humans from the negative effect of Ultraviolet lights (1mk
    2. Explain how sunlight contributes to stronger bones and teeth in human beings (2mks
  4. Name the main target organ of the following hormones: (2mks
    1. Aldosterone
    2. Insulin
  5.                              
    1. What is asexual reproduction? (1mk
    2. Give TWO disadvantages of sexual reproduction (2mks
  6. The diagram shown below represents a seeding Use it to answer questions that follow
    6 adadada
    1. Give a reason why the plant above is a member of Class Dicotyledonae (1mk
    2. Explain why the biomass of part labelled A will be lower compared to the one found in the seed stage of the same plant (2mks
  7.                          
    1. State TWO ways in which blood clotting is important to a human being (2mks
    2. What are the roles of thrombokinase enzyme during blood clotting? (2mks
  8. The diagram shown below represents a flower
    8 adadad
    1. Name the agent of pollination for the flower shown above (1mk
    2. Give TWO reasons for your answer in a) above (2mks
  9. State the differences between cones and rods in terms of the following (2mks

    Feature

    Cone

    Rod

    Visual acuity

       

    Photochemical

       
  10. Use the diagram of a nerve cell shown below to answer questions that follow
    10 sfwfdsfs
    1. With a reason, give the identity of the nerve cell (2mks
      Identity
      Reason
    2. Explain the significance of absence of part labelled H in nerve cells found in the brain (2mks
  11. Give THREE features that make modern man to be more adaptable to the environment (3mks
  12. The diagram below represents a living organism
    12 adada
    1. State TWO economic importance of the above organism in the food industry (2mks
    2. Why does the rate of respiration reduce under the following conditions? (2mks
      1. Low temperature
      2. Metabolic poison
  13. State TWO reasons why Biotechnology is important in modern science (2mks
  14.                            
    1. Fill in the table shown below to give differences between continuous and discontinuous variation (2mks

      Continuous Variation

      Discontinuous Variation

         
         
    2. Explain how variation is important in the process of evolution? (3mks
  15.                        
    1. Define the term species (1mk
    2. State TWO contributions of Carolus Linnaeus (1708 – 1778) to taxonomy (2mks
  16.                            
    1. In an experiment, Peter counted 9 cells along the diameter of field of view of a light microscope measuring 30mm Determine the diameter of one cell in micrometers (3mks
    2. Why is electron microscope safer to the eye than light microscope during use? (1mk
  17. The following diagram represents results of an experiment carried out on two sets of germinating seeds
    17 adadad
    1. Account for the result shown in test tube X (2mks
    2. What is the importance of dipping the boiled seeds in a disinfectant in test tube Y? (1mk
  18. The diagram shown below represents a section of the vertebral column
    18 adadada
    1. Name the part labelled S (1mk
    2. State TWO ways in which part T is important to movement in human beings (2mks
  19. Describe how the following cells adapt the structures where they are found to their functions
    1. Companion cell (2mks
    2. Schwann cell (2mks
  20. A mother had a still birth and the expelled foetus showed clear signs of anaemia and jaundice
    1. Give the name of this disorder (1mk
    2. Describe how the disorder arose (3mks
  21. The following equation represents a section of the Nitrogen Cycle
    21 adadad
    1. Name:
      1. Bacterium labelled Y (1mk
      2. Compound X (1mk
    2. Explain how Process Z affect plant growth in an area? (2mks
  22. Samson had a road accident resulting in serious head injuries that left him with the following conditions: Loss of balance, low body temperature; poor speech, unregulated breathing and memory loss Name the part of the brain affected that led to the following:
    1. Low body temperature ,,(1mk
    2. Memory loss (1mk
    3. Unregulated breathing (1mk
  23. The graph shown below represents effect of substrate concentration on rate of enzymatic reaction
    23 adada
    1. Account for the rate of enzymatic reaction when the substrate concentration was between 03 to 05% (2mks
    2. Name the substrates for the following enzymes
      1. Carbonic anhydrase (1mk
      2. Thrombin (1mk
  24. A tilapia fish has a full length of 300mm but measures 200mm from the mouth tip to its anus Determine the tail power of the fish (2mks

MARKING SCHEME

  1.                                
    1. Manufacture of ribosomes;
    2. Monera;
    3. Eukaryotes;
  2.                      
    1. Glycerol; Fatty acids;
    2. Requires a lot/more Oxygen to oxidise; Insoluble in water thus not easy to transport to respiratory site;
  3.                      
    1. Melanin;
    2. Influences formation of Vitamin D (in the body); Which is required for absorption of phosphates and calcium ions; important in bone and teeth formation.
  4.                    
    1. Kidney;
    2. Liver;
  5.                    
    1. Process where new off-springs arise without fertilization;
    2. Slower/takes longer time to obtain off-springs; Rely on unpredictable pollination/fertilization that are easily affected by weather changes; variation may lead to disadvantageous traits; Relies on the presence of both parents that may be possible in some cases e.g when one dies;
  6.                          
    1. Has a taproot;
    2. Stored nutrients are hydrolysed/converted to simpler forms; that are used in cell division/growth (of the seedling);
  7.                          
    1. Prevent excessive loss of blood/anaemia; Prevent entry of pathogens into the body; Initiate healing of wound;
    2. Convert prothrombin to thrombin; Neutralises anti-clotting factor/Heparin;
  8.                      
    1. Wind; Reject Wind-pollinated
    2. Has feather-like stigma; Long filament/Androecium hangs outside; Reduced petals/bracts to expose the gynoecium/androecium to wind;
  9.               

    Feature

    Cone

    Rod

    Visual acuity

    High

    Low;

    Photochemical

    Iodopsin

    Rhodopsin;

  10.                                      
    1. Identity: Sensory; Reject Unipolar
      Reason : Unipolar; Cell body off the axon;
    2. Slow down movement of impulse; to give adequate time for interpretation of the impulse (by brain/CNS);
  11. High level of intelligence/Reasoning/Brain capacity; Well-developed speech/effective communication abilities; Upright gait to see far/danger easily; Bipedal locomotion frees hands for other uses; pre-hensile hands for handling various tools; non-opposable toe for stability; 1st 3
  12.                            
    1. Baking/Manufacture of bread; Brewing Alcoholic beverages; Manufacture of high nutritional value proteins/Single Cell Protein; Manufacture of biofuel/gasohol; Food flavouring; Food conditioning/Preservation; Making vitamin supplements; Ripening of cheese; Food spoilage; Mark 1st2
    2.                            
      1. Respiratory enzymes are inactivated;
      2. Bind to the enzymes permanently or temporarily thus inhibit enzyme action on substrates;
  13. Development of new tools/techniques/procedures for biological research; Development of materials for medicine/agriculture/health/industries
    Accept specific examples e.g Drugs/Medicine/Hormones/Vaccine/Cultivars
  14.                        
    1.                     

      Continuous Variation

      Discontinuous Variation

      Determined by interaction of many genes

      Determined by one or two genes;

      Determined by interaction between genes and the environment

      Determined by the genes alone;

      Has intermediate traits between two extremes

      Lack intermediates/Has distinct groups;

      Mark 1st 2
    2. Organisms with disadvantageous variations are eliminated; those with advantageous variations adapt, survive (and reproduce); accumulation of such variations over time may lead to speciation/emergence of a new species;
  15.                          
    1. A group of organisms that are structurally similar and freely interbreed to give rise to a fertile/viable offspring;
    2. Came up with binomial nomenclature; Pioneered Modern/Natural classification/taxonomy;
  16.                            
    1. d
      9cells measure 3.0mm
      Therefore 1cell will measure: (1cell x 3.0mm)/9cells = 0.333mm;
      1mm = 1000micrometers
      Thus 0.333mm = (0.333mm x 1000micrometers)/1mm;
      Diameter of a cell = 333micrometers;
    2. Viewing of images is indirect/on screen;
  17.                      
    1. Germinating seeds utilized Oxygen in respiration; the released Carbon (IV) oxide was absorbed by Potassium hydroxide solution; (Thus reduces volume of air in the tube and level of coloured liquid rises)
    2. To preserve/Prevent decomposition/Anaerobic respiration;
  18.                      
    1. Neural spine; Reject Spine alone
    2. Create vertebral column flexibility; Absorb shock; Reduce friction/rubbing together of the adjacent vertebrae; Mark 1st 2
  19.                        
    1. Has numerous mitochondria to generate a lot of energy; for translocation of substances in the phloem;
      Large cytoplasm to store a lot of nutrients; used in respiration to supply energy for translocation;
    2. Release myelin sheath; which insulates the axon;
  20.                      
    1. Erythroblastosis foetalis/Haemolytic disease of the newborn;
    2. Arises when a Rhesus negative mother carries a subsequent Rhesus positive foetus’ pregnancy; particles of foetal erythrocytes pass to the mothers blood leading to formation and accumulation of anti-Rhesus antibodies; which pass to the foetus via placenta causing antibody-antigen reaction that destroy the foetal erythrocytes;
  21.                      
    1.                            
      1. Nitrobacter sp; Nitrococcus sp
      2. Nitrates;
    2. Low growth; due to loss of soil fertility/Nitrates important in protein synthesis;
  22.                              
    1.                              
      1. Hypothalamus; 
      2. Cerebrum;
      3. Medulla oblongata;
  23.                    
    1. No further increase in rate of reaction/Constant; Since other factors were limiting;
    2.                            
      1. Carbon (IV) Oxide;
      2. Fibrinogen;
  24. Tail power = {(300mm - 200mm)/300mm} x 100;
    = 33.3%;

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