Biology Paper 3 Questions and Answers with Confidential - Form 4 End Term 2 2021

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BIOLOGY
PAPER 3

INSTRUCTIONS TO CANDIDATES

  • Write your name and index number in the spaces provided above.
  • Sign and write the date of examination in the spaces provided above.
  • You are required to spend the first 15 minutes of the 1 ¾ hours allowed for this paper reading the whole paper carefully before commencing your work.
  • Answers must be written in the spaces provided in the question paper.

For Examiner’s Use only:-

Question

Maximum Score

Candidate’s Score

   1

14

 

   2

13

               

   3

13

 

   TOTAL

40

 


QUESTIONS

  1. Below are photographs of two specimens, J and Both of them belong to the same phylum and class. Observe them carefully before you answer the questions that follow.
    biomerp3qa1
    1. Name the class to which J and K belong and support your answer with two reasons.
      Class ………………………………………………………………………………….1mk
      Reasons                               2mks
      1. ……………………………………………………………………………
      2. ……………………………………………………………………………
    2. Suggest why the circulatory fluid in J and K has no haemoglobin.      2mks
    3. Observe their wings and suggest the type of evolution that could have taken place to give rise to J and K, and then give a reason for your answer.
      Type of evolution …………………………………………………………………1mk
      Reason ………………………………………………………………………………………………………………………………………………2mks
    4. Below is a diagram showing the life cycle of specimen J.
      biomerp3q1d
      1. Identify the stage labeled D. ……………………………………………………..1mk
      2. Name the hormone responsible for the change from D to A. 1mk
      3. Explain the differences in the change from C2 to C3 and from C3 to D.         4mks

Q2. Study the organisms   below and answer questions in spaces provided .
biomerp3q2

  1. Complete and use the key below to identify the organism.   2mks
    1a. Organism with endoskeleton ………………………………………… go to 2
    1b. ______________________ ………………………………………………… go to 3

    2a. Has scales on the body………………………………………………… go to 4
    2b. Has no scales on the body…………………………………… mammalian.

    3a. Has cephalothorax ………………………………………………… Arachnida.
    3b. Has no cephalothorax………………………………………………go to 5

    4a. __________________________________............................... pisces
    4b. Has no fins …………………………………………………….. Go to 7

    5a. Has three pairs of legs …………………………………………… Insects.
    5b. Has more than three pairs of legs …………………………… go to 6

    6a. Two pairs of legs per segment ……………………………………Diplopoda
    6b. One pair of legs per segment………………………………………chilopoda.

    7a. Has feathers ……………………………………………………………… Aves
    7b. Has no feathers …………………………………………………………go to 8

    8a. Has a tail…………………………………………………………………Reptilia
    8b. Has no tail……………………………………………………………Amphibia.

  2. Identify the organisms above using the completed key above. 6mks
    Specimen  Steps followed Identity 
     A    
     B    
     C    
     D    
     E    
     F    
  3. Name the phylum in which specimens C, E and F belong to ……………………………………………..1mk

  4. Give three reasons for your answer in (c).   3mks

  5. Name one feature that is common in organisms Band E.   1mk

Q3.You are provided with a specimen labeled which is a fruit. Use it to answer the questions that follow.

  1. Make a transverse section of the specimen T. Draw and label at least 3 parts.                 6mks
  2. With reasons, state the identity of fruit
    Type of fruit………………………………………………………………………..1mk
    Reason …………………………………………………………………………………1mk
  3. Suggest the possible agent of dispersal and give two reasons
    Agent …………………………………………………………………………………1mk
    Reason ………………………………………………………………………………………………………2mk
  4. What is the placentation of T? …………………………………………………….1mk
  5. Specimen was green in colour before it was treated with a plant hormone.
    Suggest the plant hormone.………………………………………………………………………………………1mk


Marking Scheme

  1. Below are photographs of two specimens, J and K. Both of them belong to the same phylum and class. Observe them carefully before you answer the questions that follow.
    biomerp3qa1
    1. Name the class to which J and K belong and support your answer with two reasons.
      Class         Insecta;         1mk Rej. insect
      Reasons                                       2mks
      i). Six legs; three body parts; two antennae; two compound eyes;
    2. Suggest why the circulatory fluid in J and K has no haemoglobin.       2mks
      Haemoglobin used to transport oxygen/ carbon (IV) oxide in the body; oxygen is taken directly to tissues/ carbon (IV) oxide taken directly from tissues by tracheoles; 
    3. divergent evolution;                       1mk
      Reason one pair of wings in J reduced to halters/ are vestigial; but both are functional in K 2mks
    4.                  
      1. pupa stage; 1mk
      2. Ecdysone; accept Moulting hormone  1mk
      3. 4mks
        C2 to C3 – moulting hormone / Ecdysone induce moulting; but presence of juvenile hormone prevent formation of pupa;
        C3 to D – moulting hormone / Ecdysone induce moulting; but abscence of juvenile hormone lead to formation of pupa;
  2.                              
    1. 1b – organism with exoskeleton
      4a. – has fins
    2.                        
      Specimen  Steps followed Identity 
       A 1a, 3a Arachnida
       B 1a, 2a, 4a Pisces
       C 1b,3b, 5b, 6b Chilopoda
       D 1a, 2a, 4b, 7b, 8a Reptilian
       E 1a, 2a, 4b, 7a, Ave
       F 1b, 3b, 5a Insect
    3. Arthropoda
      rej: Anthropoda or arthropoda

    4. They all have exoskeleton
      They have segmented bodies
      They all have jointed appendages/limbs

    5. Scales


3.     

  1.                  
      biomerp3qa3a5mks
    Magnification between X1 and X5
  2. Type of fruit Berry 1mk
    Reason has many seeds 1mk

    Agent Animal 1mk
    Reason brightly coloured; scented; fleshy; large; first 2mk

  3. Axile; 1mk
  4. Ethylene/ ethyne; 1mk


CONFIDENTIAL

Each candidate should have:

  • One ripe banana
  • Scalpel/blade

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