Biology Paper 1 Questions and Answers - KCSE 2022 Mock Exams Set 2

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Questions

INSTRUCTIONS

  • All Questions are Compulsory
  • Wrong Spelling of Technical Terms shall be Penalized

 

  1. State TWO ways in which the study of Biology has helped the world in the accelerated fight against the recent Covid-19 pandemic. (2mks
  2.        
    1. Give ONE function of centrioles (1mk
    2. Name a Kingdom in which all members lack centrioles in their cells (1mk)
  3.  
    1. Name the skin pigment formed by cells in the mammalian skin
    2. Which genetic disorder is associated with the absence of the pigment named in 2a)?
    3. How does the skin pigment help protect human beings against skin cancer?(1mk)
  4. Explain the following observations
    1. More water hyacinth plants are found growing along the shore of Lake Victoria than in the deep waters (1mk)
    2. Green plants grow faster in lower altitudes areas than in higher altitude areas (2mks)
  5. State TWO functions of a cover slip in light microscope work (2mks)
  6. Use the diagram of the heart shown below to answer the questions that follow
    Biocsp1q6
    1. From the diagram, give a reason to show that X is the left ventricle (1mk)
    2. Name a class of organisms where all members have the heart structure above(1mk)
    3. Why are the muscles found in the heart above said to be myogenic? (1mk)
  7. Account for the following
    1. Red blood cells lack mitochondria (1mk)
    2. The testes are found hanging outside the body in male human beings (1mk)
  8.  
    1. Why is pancreas said to be a dual gland? (1mk)
    2. Name the endocrine tissue in the pancreas (1mk)
  9. A student made a set up shown below to study a physiological process
    Biocsp1q9
    1. In which beaker did the dialysis tubing reduce in size? (1mk)
    2. Account for your answer in a) above (2mks)
  10. The diagram below shows a graph of body temperature of two different organisms against changing environmental temperature
    Biocsp1q10
    1. State the name used to refer to animal A in terms of thermoregulation (1mk)
    2. State TWO advantages animal B has over animal A (2mks)
  11. The diagram shown below is of a flower
    Biocsp1q11
    1. Name the agent of pollination for this flower (1mk)
    2. Give TWO adaptive features from the diagram to support your answer in a) above (2mks)
  12. The process of gamete formation is represented below|
    Biocsp1q12
    1. State a reason why the process above represents gamete formation in female mammals (1mk)
    2. Name the chromosomal mutation represented above (1mk)
    3. Identify the genetic disorder that arise when the following gametes are fertilized
      1. P (1mk)
      2. Q .(1mk)
  13. A sample of air was passed through pyrogallic acid and its volume reduced from 8 cm3 to 7 cm3. When it was later passed through lime water, the volume reduced to 6.8cm3.
    1. What was the role of pyrogallic acid in this experiment? (1mk
    2. Determine the percentage of Carbon (IV) oxide in the sample of air (2mks
    3. Is this sample of air exhaled air or inhaled air? (1mk
  14. The stage-wise process of germination of a seed is shown below
    Biocsp1q14
    1. Give a reason why the diagram above represents hypogeal germination(1mk
    2. Account for the change in dry weight of the cotyledon at stage X and Y(2mks
  15. Barbra observed animal cells in a field of view of a light microscope as shown below. If she used a total magnification of X1000 determine the actual diameter of one cell(3mks)
    Biocsp1q15
  16. Explain the importance of the following features
    1. Acrosome in the spermatozoa(2mks)
    2. Hair-like structures in the fallopian tube(1mk)
  17.  
    1. What are vestigial structures?(1mk)
    2. Explain why divergent evolution is advantageous to living organisms?(2mks)
  18. The various stages of mitosis are represented below
    Biocsp1q18
    1. Identify the stages represented by the letters:
      1. D .(1mk)
      2. E (1mk)
    2. What shows that the process represented above is taking place in a plant cell?(1mk
  19. The diagram shown below represents the various nerve cells
    Biocsp1q19
    1. Use arrows to show direction of impulse in a reflex arc in the diagram above (1mk
    2. Outline expected TWO structural differences between nerve cell R and X(2mks
  20. State the function of the following muscles in the body
    1. Cardiac sphincter muscles(1mk
    2. Erector pili muscles(1mk
  21. The diagrams below are of seedlings before and after an experiment.
    Biocsp1q21
    1. Under which light condition was the experiment carried out.(1mk
    2. Which term describes the appearance of the seedlings at the end of the experiment(1mk
    3. What is the importance of the above experiment in crop production?(1mk
  22. State the function of the following cells in the body of organisms
    1. Palisade.(1mk
    2. Schwann(1mk
    3. Sertoli(1mk
  23.     
    1. Mary suspects that she has diabetes mellitus. Using a sample of her urine describe a school laboratory procedure she can follow to confirm it is true(3mks
    2. Why is insulin not administered orally?(1mk
  24. The following is an illustration of a bone
    Biocsp1q24
    1. Give the name of the bone.(1mk
    2. State an advantage of the joint formed at the part labelled M(1mk
    3. State the function of the part labelled N.(1mk
  25.        
    1. Distinguish between population and community as used in ecological studies(2mks
    2. State the formula for population estimation using capture recapture method(1mk
  26. The diagram below shows the structure of germinating pollen grain
    Biocsp1q26
    1. Name the type of cell division that formed the parts labelled A(1mk)
    2. State the role of part labelled B(1mk)
  27. The picture of a common animal is represented below
    Biocsp1q27
    1. Name the class to which the organism shown above belongs.(1mk)
    2. Give TWO reasons for your answer in a) above(2mks)
  28. The following experimental set up was placed in sunshine to investigate a biological process
    Biocsp1q28
    1. Account for the expected result in the level of water in the beaker labelled B.(2mks)
    2. Why were the set up C and D included in the experiment?.(1mk)

Marking Scheme

  1. Knowledge on its cause; Knowledge on how the virus spreads; Increased knowledge on how to control the spread/containment measures; development of vaccines; global cooperation in research/fight against the virus; Mark 1st 2
  2.  
    1. Formation of Spindle fibers; Formation of flagella/cilia;
    2. Plantae; Monera;
  3.   
    1. Melanin
    2. Albinism;
    3. Absorbs UV/Ultraviolet rays;
  4.  
    1. Eutrophication/Enrichment of water by pollutants;
    2. Higher concentration of Carbon (IV) Oxide; thus higher rate of photosynthesis;
      Conducive/Optimum temperatures; thus faster rate of metabolism\Activated enzymes;
  5. Exclude dust/contaminants; Prevent dehydration; Hold specimen in position; OWTTE
  6.  
    1. Thicker muscular wall;
    2. Mammalia; Aves;
    3. Contract without nervous stimulation/Initiate contraction on their own;
  7.  
    1. To prevent oxygen utillisation for efficient transport;
    2. To Create conducive/optimum temperature for sperm formation/ spermatogenesis;
  8.  
    1. Has endocrine and exocrine function/Forms both/ hormones and enzymes;
    2.  Islet of Langerhans;
  9.  
    1. A;
    2. Sucrose solution is hypertonic; thus it gains water molecules by osmosis;
      Accept: Water is hypotonic; thus water molecules move into the dialysis tubing by osmosis;
  10.    
    1. Poikilotherm; Accept Ectotherm/Ectothermic/Poikilothermic Rej cold blooded
    2. Can live in any habitat; Is More active both day and night;
  11.  
    1. Wind
    2. Long filament; Anthers hanging outside; Feather/Net-like stigma; Smaller bracts to allow the stigma/anthers to be exposed to wind;
  12.  
    1. Only X chromosomes are involved;
    2. Non-disjunction;
    3.      
      1. Turner’s Syndrome;
      2. Klinefelter’s Syndrome;
  13.   
    1. Remove Oxygen;
    2. % of CO2 =[(7cm3 – 6.8cm3) X 100] ÷ 8cm3; Deny if Units Omitted
      = [0.2 cm3 X 100] ÷ 8cm3
      = 2.5%; Deny if % symbol missing
    3. Exhaled air;
    1. Cotyledon is found below the ground surface; elongated epicotyl;
    2. Decreases; since stored nutrients are hydrolyzed to facilitate growth/germination/cell division;
  14. 3cells measure 1.5mm
    Therefore 1 cell will measure?
    = (1cell X 1.5mm)/3cells; =0.5mm Deny if Units Omitted
    Magnification = image length/actual length
    Thus Actual length =image length/magnification
    =05mm/1000; Deny if Units Omitted
    =0.0005mm; Deny if Units Omitted
  15.  
    1. Release lytic enzymes; that Neutralize secretions/destroy/digest vitelline and cell membrane for entry of sperm head into the ovum;
    2. Waft/push the ovum/zygote/blastula towards the uterus;
  16.  
    1. Structures that have lost function thus become smaller;
    2. Development of necessary adaptations; to survive a give habitat/conquer different habitats;
  17.  
    1.    
      1. D-Telophase;
      2. E-Anaphase
    2. Laying of a Cell plate/Cellulose deposits to separate the daughter cells; Centrioles/Spindle fibers are not involved/seen;
  18.  
    1.    
      Biocsp1qa19    
    2. Differences
       R  X
       Unipolar  Multipolar/Bipolar;
       Has Myelin Sheath  Lacks Myelin Sheath;
       Has Nodes of Ranvier  Lacks Nodes of Ranvier;
       Has Schwann cells  Lacks Schwann cells;
       Long Axon  Shorter axon;
      Award the 1st 2
  19.       
    1. Cardiac sphincter muscles: Relaxes to allow entry of food/food bolus into the stomach/Prevent exit of food from stomach to oesophagus/gullet;
    2. Erector Pili Muscles: Contracts and relaxes to make the body hairs straighten or lie flat on the body;
  20.  
    1. Low/dim; Accept darkness;
    2. Etiolation;
    3. Increase productivity of Dwarf plants;
  21.  
    1. Photosynthesis;
    2. Secretion of myelin sheath;
    3. Nourish young sperm cells; point of attachment of sperm cells as they develop;
  22.   
    1. Place 2ml of her urine in a boiling tube
      Add Equal amount/2ml of Benedict’ solution;
      Boil;
      Green/Yellow/Orange/Brown colour change would show a positive test/result;
    2. It may be digested (since it is protein in nature);
  23.  
    1. Innominate bone/Half pelvic girdle; REJ Pelvic girdle alone
    2. Achieves movement in all planes; Achieves a 3600 rotation thus greater flexibility;
    3. Passage of blood vessels/nerve fibers to lower regions of the hind limbs; Reduces weight/density at the hip region;
  24.  
    1. Population is a group of organisms of same species found in the same place at the same time; while Community is different populations/group of animals and plants living in the same habitat; Award 0, 1 or 2 mrks
    2. Population = [First Marked X Second Capture] ÷ Marked Recaptured
      REJ Abbreviations
  25.  
    1. Mitosis;
    2. Regulate Growth of pollen tube;
  26.  
    1. Mammalia; REJ Mammals/mammmalia/Mammmalian
    2. Body fur/hair; Heterodont dentition/Different types of teeth; Presence of Ear pinna; 1st 2
  27.  
    1. Remained the same; all the stomata blocked by jelly thus no water uptake/loss/transpiration;
    2. Act as a Control experiment;

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