Biology Paper 1 Questions and Answers - 2021 KCSE Eldoret Diocese Mock Exams

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Questions

INSTRUCTIONS TO CANDIDATES

  • Spelling errors especially of biological terms shall be penalized
  • Candidates should answer the questions in English.

  1. Name the group of organisms that are found on the boarder of living and non-living organisms [1mark]
  2. State two features characteristic of fruits dispersed by animals [2marks]
  3. Define each of the following biological phenomena
    1. Irritability [1 mark]
    2. Seed dormancy [1 mark]
    3. Double fertilisation in angiosperms [1 mark]
  4. Name the disease condition caused by deficiency of each of the following
    1. Iodine [1mark]
    2. Vitamin B1 [1 mark]
  5. State the function of the mitochondrial cristae [1 mark]
  6. Give the difference between transpiration and guttation [2 marks]
  7. Name two enzymes in the human digestive system which are secreted in an inactive form [2 marks]
  8. Outline the function of the cilia in the mammalian fallopian tube [1 mark]
  9. Name the blood vessel that supplies blood to the
    1. Brain [1 mark]
    2. Cardiac muscle [1 mark]
  10. Explain why when placed in fresh water Entamoeba histolytica does not burst [2 marks]
  11.        
    1. Name the taxonomic class of woodlice [1 mark]
    2. Name two other organisms in the taxonomic class in (a) above [2 marks]
    3. State two features characteristic of organisms in the taxonomic class in (a)(i) above [2 marks]
  12. To estimate the population size of grasshoppers in the 5km2 field behind the Matope school farm, a group of students caught 100 grasshoppers on the first day. They marked them and released them back into the field. 48 hours later, the students went back to the field and caught 80 grasshoppers. Of these, 40 were found to have been marked
    1. Suggest a suitable method used to mark the grasshoppers [1 mark]
    2. Calculate the population density of grasshoppers in the field [3 marks]
  13. The diagram below shows a specialized plant cell
    Eld21Biop1q13
    1.        
      1. Identify the cell [1 mark]
      2. State one feature observable in the diagram above that adapts the cell to its function[1 mark]
      3. Name the part labelled F [1 mark]
  14. Shown below is a diagram of a neurone
    Eld21Biop1q14
    1.            
      1. Identify the type of neurone in the diagram above [1 mark]
      2. Give one reason for your answer in (a)(i) above [1 mark]
    2. Draw an arrow, alongside the diagram above, to indicate the direction of flow of a nerve impulse in the neurone [1 mark]
  15. Study the equation below which represents a reaction which takes place in the mammalian body
                              Enzyme X
    CO2(g)+ H2O(l)      →      H2CO3(aq)
    1. Where in the mammalian body does the reaction above take place? [1 mark]
    2. Name the enzyme X [1 mark]
  16. The diagram below shows a specialized cell from a human being
    Eld21Biop1q16
    1. Name the part labelled P [1 mark]
    2. Give one adaptive feature of the organelle labelled T [1 mark]
    3. State the function of the part labelled Q [1 mark]
  17. The apparatus shown in the diagram below may be used to demonstrate aerobic respiration. Air is drawn through the apparatus by attaching it to a vacuum pump at the point labelled X. Sodium hydroxide solution is placed in flask 1 to remove carbon(IV)oxide
    Eld21Biop1q17
    1. Why was it necessary to remove carbon(IV)oxide? [1 mark]
    2. Calcium hydroxide solution is put in the jars labelled 2 and 3. Explain why [2 marks]
      Jar 2………………………………………………………………………………………………………
      Jar 3………………………………………………………………………………………………………
    3. Suggest a suitable control for this experiment [1 mark]
  18. Illustrated below is the movement of material in a certain physiological process
    Eld21Biop1q18
    1.          
      1. Name the physiological process illustrated above [1 mark]
      2. Give two examples of applicability of the process named in (a)(i) above in plants [2 marks]
    2. State two ways by which the movement of the dye molecules would be slowed down [2 marks]
  19. The diagrams below represent an experimental set up to investigate a certain biological phenomenon
    Eld21Biop1q19
    1.        
      1. What was being investigated in the experiment? [1 mark]
      2. Explain your answer in (a)(i) above [3 marks]
    2. What was the role of flask II in the experiment? [1 mark]
  20. Outline two adaptive features of guard cells [2 marks]
  21. The scientific name of the European wildcat, a nocturnal mammal that inhabits forests of Western, Southern, Central and Eastern Europe, is Felis silvestris. Write down
    1. the scientific name of the European wildcat [1 mark]
    2. the species name of the European wildcat [1 mark]
  22. Name the hormone, in man, responsible for each of the following
    1. Stimulates secretion of bile by hepatocytes [1 mark]
    2. Stimulates release of bile juice from gall bladder into the duodenum [1 mark]
  23. The following text messages on a cellular phone represent gene mutations
      Intended message Actual message
     I Metere is a top school Metre is a top school
    II  The microscope is my tool The microscope is my loot
    Identify the type of gene mutation represented in each case
  24.      
    1. Define omnivores [1 mark]
    2. Name two mammals that are omnivores [2 marks]
  25.     
    1. Two alleles in heterozygous state can be fully expressed phenotypically in an organism e.g. the alleles for black and white skin colour in guinea pigs (Cavia porcellus). Give the term used to describe this phenomenon [1 mark]
    2. Give one example of a trait in human beings where the condition whose term is named in (a) above expresses itself [1 mark
  26. Shown below are diagrams of the same mammalian blood cell
    Eld21Biop1q26
    State two morphological features of cell represented in the diagram above [2 marks]
  27. The table below shows the effect of wind, still air and stomatal opening on the rate of transpiration of a plant in milligrams of water lost per hour dm2. Study the table and answer the following questions
    Stomatal opening (μm) 1 2 3 4 5 6 7
    Windy 40 63 74 86 94 110 124
    Still air 0 6 12 19 23 27 30

    1.            
      1. Compare the rates of transpiration in windy and still air conditions [1mark]
      2. Explain your observation in a(i) above [2marks]
    2. How does stomatal opening affect transpiration rate? [1mark]
  28. The relationship between oxygen concentration, potassium uptake and sugar consumption in isolated barley roots was determined. The loss of sugar and potassium uptake are in arbitrary units
       Percentage oxygen in aeration stream      
    0 5 10 15 20 100
    Sugar loss  15 20 42 45 45 48
    Potassium gain 5 55 70 73 75 70

    1.  Account for the sugar loss and potassium gain at between 5% and 20% oxygen concentration [3marks]
    2. State two ways in which you can stop the above process from taking place [2marks]
  29. Illustrated in the diagrams below is the position of chloroplasts (shown as dark structures, ) in a tropical plant species, at two different times of the day
    Eld21Biop1q29
    1. Identify the tissue labelled K [1 mark]
    2. Name the response shown by the chloroplasts in diagram I [1 mark]
    3. Outline the importance of the orientation of the chloroplasts as illustrated in diagram II [2 marks]

Marking Scheme

  1. Viruses ;
  2.  Fruits/ a part of the fruit is, fleshy/ juicy/ succulent (Fruits/ a part of the fruit is brightly coloured. Fruits large-sized and thus conspicuous (acc. Clustered rej conspicuous alone) fruits scented/ with a sweet smell/ aroma; seeds have tough/ hard/ slimy testa; (ej coat alone for testa, Accept seed coat for testa) seeds covered with sticky/ mucoid/ slimy materials (the fruit/ parts of the fruit) have hooks/ hook-like structures (mark the first floor (1 mk x 2= 2 mks)
  3.              
    1. Irritability
      - Ability of a living thing/ organism to detect/ perceive and react to a change in its environment (note both/ the two underlined aspects of the phenomenon must be stated to score 1 mk)
    2. seed dormancy
      - Inability of seed of a given plant to germinate (caused by conditions within the seed) in a specified period of time. Under environmental factors/ conditions that are normally suitable/ ideal o germination (of the non-dormant seed) (Note: both aspects of seed dormancy must be specified to score 1mk)
    3.  Double fertilization
      - One of the male nuclei fuses with the egg cell nucleus to form diploid zygote while the other male nucleus fuses with the polar nucleus to form triploid primary endosperm
  4.    
    1. Goitre
    2. beriberi
  5. increase surface area for attachment of respiratory enzymes hence increased rate of respiration
  6.      
    Transpiration Guttation
    Loss of water from a plant surface in from of water vapour Loss of water from a plant surface in form of liquid droplets
    Take place/ water is lost through stomata, lenticels, thin cuticle Takes place/ water is lost though hydathodes;
  7. pepsin secreted as pepsinogen
    Trypsin secreted as trypsinogen
  8. cilia waft to propel the ovum in the fallopian tube
  9.          
    1. carotid artery
    2. coronary artery
  10. Has contractile vacuoles that collect and discharge excess water out of the cell
  11.        
    1. Name taxonomic class of woodlice
      - (class) Crustacea (NB initial ‘C’ must be written in upper case while others in small letters
    2. Name two other organisms in the taxonomic class in (a) (i) above
      - Crab/ lobster/ catfish, Bamades, Krill
    3. State two features characteristics/ diagnostic o organisms in the taxonomic class in (a) (i) above
      - Bitamoua (two pated) appendices; two body [parts; cephalothorax covered dorsally with carapace/ hard shell like structure, two pairs of antennae; Chitinous exoskeleton/ segmented body (paired and )jointed appendages/ each body segment with a pair of appendages/ dorsal, tubuler heart/ open circulatory system/ internal body cavity a haemocoel through which haemolymph circulates and in which internal body organs suspended/ vision by means of compound and simple eyes/ Excretion by means of malphigian tubules.
  12.     
    1. Suggest a suitable method used to mark the grasshopper
      • Applying nail polish/ varnish, using permanent marker pen/ felt pen
    2. Calculate population density of grasshoppers in the field.
      • Population size = first marked/ captured x second capture
                                     Marked re-captured
        = 100 x 80
                40 = 200 grasshoppers
        Population density = 200 grasshoppers
                                              5km2
        = 40 grasshoppers/km2
  13.             
    1.      
      1. Identify the cell
        • Root hair
      2. State 1 feature observable in the diagram above that adapts the cell to its function of absorption of water and mineral ions
        • Has an elongated portion to increase surface area over which water and mineral ions are absorbed
    2. Name the part labeled F
      • Sap vacuoles
  14.             
    1.        
      1. Identify type of neuron in the diagram above
        • Motor/ Efferent neurone
      2. Give one reason for your answer in (a) (i) above
        • Cell body located at one end/ the edge of the cell
    2. Draw an arrow alongside diagram above to indicate direction of flow of nerve impulse in the neurone.
      Eld21Biop1qa14
  15.          
    1. Where in the mammalian body does the reaction above take place?
      • In red blood cells in the blood capillaries in the tissues with high carbon (IV) oxide concentration.
    2. Name enzyme X
      • Carbonic anhydrase

  16.                   
    1. Name the part labeled P
      • Acrosome
    2. Give one adaptive feature of the nucleus – the organelle T.
      • Carried haploid/ half the normal number of chromosomes of the species; so that following fertilization, the normal diploid condition of the species is reconstituted; rej. Contains the nucleus synthesis of ribosomes; rej. Semipermeable membrane for selective movement of materials between the nucleoplasm and the rest of the cell (NB- the core function of the nucleus in the sperm cell is reproduction. The latter are auxiliary roles of the organelle.
    3. State function of Flagellum/ tail – pat Q
      • Forward- Propulsion of the cell.

  17.   
    1. Why is it necessary to remove carbon (IV) oxide
      • Confirm that any carbon (IV) oxide present/ detected is from the animal and not from the incoming air.
    2. Calcium hydroxide solution is put in the jars labeled 2 and 3, explain why
      • - Jar 2 – to confirm that the incoming air is Carbon (IV) oxide – free
      • - Jar 3 – to test for Carbon (IV) oxide in the air exhaled by the small animal.
    3. Suggest suitable control for this experiment
      • Same set up but without/ excluding the animal

  18.             
    1.              
      1. Name the physiological process illustrated above
        • Diffusion, rej. Osmosis
      2. Give two examples of applicability of the process named in (a) (I above in plants
        • Gaseous exchange/ Taking in of oxygen and excretion of carbon IV) oxide
        • Translocation of materials (in phloem tissue
        • Absorption/ uptake of mineral ions/ salts
    2. State 2 ways by which movement of the dye molecules would be slowed down.
      • Lowering the temperature of the medium
      • Increasing thickness of the membrane (to increase the diffusion distance
      • Use a smaller quantity of the dye
      • Add more water to reduce the concentration gradient.
  19.             
    1.            
      1. What was being investigated in the experiment?
        • Positive – hydrotaxis in ants/ Response of ants to water.
      2. Explain your answer in (a) (i) above
        • Ants moved into the flask containing (cotton wool soaked in) water; to be able to obtain water for their metabolism. No ants moved into the dry flask.
    2. What was the role of flask II in the experiment?
      • Serve as a control.

  20. Outline 2adaptive features of guard cells
    • Inner/ proximal/ventral wall in thicker and thus less elastic than the outer/ distal/ dorsal wall; the converse- the outer/distal/dorsal wall is thinner and thus elastic than the inner/ proximal/ ventral wall) and thus when the cells are turgid, the outer wall stretches more while the inner wall resist enlargement making the cells burg outwards leaving a pore-stoma in between.
    • Contain chloroplasts and thus carry out photosynthesis; forming glucose (an osmotically active chemical substance) which increases osmotic pressure of the guard cells, water molecules them move into the cells by osmosis (resulting into opening of the stomatal pore.

  21.          
    1. The scientific name of the European wildcat
      • Felis silvestris
    2. The species/ specific name/ epithet of the European wildcat
      • silvestris; NB: all letters in this word must be lower case, to score.

  22.         
    1. secretin
    2. cholecystokinin

  23. Identify type o gene mutation represented in each case
    • I – Deletion (of gene ‘e’)
    • II – Substitution/ inversion

  24.               
    1. Define omnivores
      • Animals that acquire energy and nutrients from materials of plant and animal origin. Omnivores are strictly animals.
    2. Name two animals that are omnivores
      • Man (rej men) human/ human being/, bear, hedge dog, skunk, squirrel, Raccoon, mouse, rat. Chimpazee, orangutan, Armadilo, Monkey (Accept the plural’s/ humans beings, pigs, badgers etc)

  25.                 
    1. Give the term used to describe this phenomenon
      • Codominance (written as one word)
    2. Give one example of a trait in human beings where the condition whose term is named in (a) above express itself.
      • Type AB blood group/ type, rej blood group/s alone, rej ABO blood group/s acc. Sickle cell trait rej. Sickle cell disease/ sickle cell anaemia.

  26. State 2 normal morphological/ physical features of the mammalian red blood cell represented in the diagram above
    • Biconcave
    • Lacks nucleus/ anucletae

  27.                  
    1.         
      1. rate of transpiration is higher in windy than in still air condition
      2. wind blows off water vapour from the surface of the leaf ;thus raising the saturation deficit hence increasing rate of transpiration;
    2. widened stomatal aperture increases the surface area for transpiration

  28.               
    1. increase in oxygen concentration results in corresponding increase in amount of sugar loss and potassium gain; oxygen gas is used to oxidize the sugar during respiration to generate energy needed for active uptake of potassium ions;
    2.              
      • introducing enzyme inhibitors;
      • reducing/eliminating oxygen gas and sugar;

  29.              
    1. Identify the tissue labeled K
      • Palisade/ mesophyll (tissue)
    2. Name the response (to sunlight) sown by the chloroplasts in diagram I
      • Positive phototaxis/ positive phototactic response rej. Phototaxis alone, rej positive phototropism.
    3. Outline importance of the orientation of the chloroplasts as illustrated in diagram II i.e why do chloroplasts move away from bright sunlight?
      • Chloroplasts move away from bright/high-intensity sunlight (at 2pm) to avoid solarisation / destruction/ photo –oxidation) of chlorophyll (molecules) by high – intensity/ very bright sunlight.

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