BIOLOGY PAPER 3 - FORM 4 END TERM 1 EXAMS 2020

Share via Whatsapp

Answer all the questions in the spaces provided.

  1. You are provided with substance L. Carry out food tests on the substance using the reagents provided. Record your procedure, observations and conclusions in the table below. (9mks)

    Food substance

    Procedure

    Observation 

    Conclusions

           
           
           
  2.  
    1. During a visit to a museum, students were shown ten specimens of organisms on display. The teacher provided a dichotomous key (shown in a separate page) to enable them to place each species on display into its taxonomic group. Five of the specimens that were on display are shown in the diagrams provided.
      Dichotomous Key.
      1. (a) Animal with a flattened body….. …………………………………..go to 9.
        (b)Animal without a flattened body……………………………………. go to 2.
      2. (a)Animal with body in a shell ………………………………………….Mollusca.
        (b)Animal with body in shell………………………………………….. go to 3.
      3. (a)Animal with segmented body….. …………………………………….go to 4.
        (b)Animal with body not segmented…………………………………….Nematoda.
      4. (a)Animal with jointed appendages go to 6.
        (b) Animal without jointed appendages to 5.
      5. (a)Animal with long and cyndrical body…………………………………..annelida.
        (b)Animal with short stout body………………………………………….. Trenada.
      6. (a) Animal with antennae…………………………………………………...go to7.
        (b) Animal without antennae ….. ………………………………………….go to 8.
      7. (a)Animal with one pair of antennae……………………………………… Insecta.
        (b) Animal with more than one pair of antennae………………………….. crustacean.
      8. (a)Animal with pincer –like mouthparts………………………………….. Arachida.
        (b) Animal with sucking mouth parts………………………………….….Acarina.
      9. (a)Animal with long ribbon-like body ……………………….…………….cestoda.
        (b) Animal with circular body………………………………………….. rinoidea).
        Use the dichotomous key to identify the taxonomic group of each of the five specimens shown in the drawings.
        specimens biop3
        In each case, show in sequence the steps (ef 1a,2a,5a, 7b) in the key that you followed to arrive at the identity of each specimen.(5mks)
        Animal                       Steps followed                           Identity
        E                                 ………………………….       ……………………………
        F                                  …………………………        ……………………………
        G                                 …………………………        ……………………………
        H                                 …………………………        ……………………………
        J                                   …………………………        ……………………………
    2.  
      1. Name the phylum and the class to which specimen M belongs (2mks)
      2. Name the observation features that enabled you to place it in the class above. (3mks)
    3. With the help of a hand lens, examine the body of specimen M.
      1. State with a reason in each case he observable features that enable the specimen to be a disease vector. (2mks
      2. Name one disease transmitted by specimen M.(1mk)
      3. State two methods that can be used to prevent specimen M from spreading diseases. (2mks)
  3. You are provided with specimens labeled S1 S2 and S3
    1. Using a scarpel blade split S1 longitudinally and draw a well labeled diagram to show the internal structures. State your magnification (4mks)
    2. With a reason, state the class to which the plant from specimen S1 belongs to.
      Class(1mk)
      Reason(1mk)
    3. Specimen S2 is a germinated seedling of S1. In the table below, name three structures and say which structure in S1developed into the structure in S2.

      Structure in S1

      Structure in S2

         
    4.  
      1. Using specimens Sand S3 ,name the type of germination in :-
        S1
        S3 (1mk)
      2. Give the difference between the this type of germination in (d) (i) above (2mks)
      3. Account for the type of germination in :-
        S1 2mks
        S3 (2mks)


MARKING SCHEME


  1. Food substance

    Procedure

    Observation

    Conclusion

    Starch

    To a little of substance L

    in a test tube,add a little iodine

    Blue-blackcolour forms

    Starch present;

    Reducing sugar

    To a little of substance L in a test tube   add equal amount of Benedict’s solution and heat to boil.

    Colour remains blue

    Reducing sugars

    absent

    Proteins

    To a little L,add a little sodium hydroxide followed by a little copper(II) sulphate solution and shake the mixture.

    Purple colour forms

    Protein present;

    (9mks)
  2.  
    1. Animal Steps followed                                   Identity
      E                            1b,2a;                                      Mollusca
      F                            1b,2b,3a,4a,6a,7b;                   Crustacea;
      G                           1b,2b,3a,4a,6b,8a;                   Arachnida;
      H                           1b,2b,3a,4b,5a;                        Annelida;
      J                             1a,9a;                                       Cestoda; Each entry ½mk
    2.  
      1. Phylum: Arthropoda(1mk)
        Class:Insecta     (1mk)
      2.  
        • Has three body parts;
        • Has three pairs of legs
        • Has one pair of wings;
        • Has one pair of antennae; max 3mks
    3.  
      1.  
        • Presence of legs that walk on contaminated surfaces;
        • Presence of wings that facilitate movement to and from contaminated surfaces;
        • Hairly body on which disease causing microorganisms attach;
        • Has a proboscis to suck /contaminate food;    any 2 (2mks)
      2. Cholera/dysentery(1mk)
      3.  
        • Covering food;
        • Proper disposal of waste /rubbish;
        • Eradication of houseflies using insecticides; any 2 (2mks)
  3.  
    1.  
      • Magnification – 1mk.
      • Each correct label-½ mk.
      • Correct drawing (1mk)
    2. Class: Dicotyledonae;(1mk)
      Reason :Has two cotyledons has network veins /has at a tap root system.(1mk)
    3.  

      Structure in S1

      Structure in S2

      Plumule

      Radicle

      Cotyledon

      Stern system /shoot

      Root system;

      Seed leaf

      Max 2
    4.  
      1. S1 – Epigeal (1mk)
        S3 – Hypogeal (1mk)
      2.  

        S1

        S3

        -Cotyledons pushed above the ground

        -Hypocotyl elongates

        -Cotyledons remain in the soil

        -Epicotyl elongates

        2mks
      3. S1- has little food store; hence leaves develop early to start photosynthesis ; (2mks)
        S3- has a lot of food stored; which is enough for early growth, hence no need for early photosynthesis ;( 2mks)

Download BIOLOGY PAPER 3 - FORM 4 END TERM 1 EXAMS 2020.


Tap Here to Download for 50/-




Why download?

  • ✔ To read offline at any time.
  • ✔ To Print at your convenience
  • ✔ Share Easily with Friends / Students


Join our whatsapp group for latest updates
Get on WhatsApp Download as PDF
.
Subscribe now

access all the content at an affordable rate
or
Buy any individual paper or notes as a pdf via MPESA
and get it sent to you via WhatsApp

 

What does our community say about us?

Join our community on:

  • easyelimu app
  • Telegram
  • facebook page
  • twitter page
  • Pinterest