Dichotomous Key and photomicrograph

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PAPER 3

  1. The photograph below shows the arrangements of different type of cells and tissues in a certain living organism. Study it and answer the questions that follow.

     

 

 

 

 

 

 

 

 

 

 

 

 

  1. a) i) From what part of the plant was the photograph obtained.                  (1 mark)

 

 

 

  1. ii) Name the parts labeled.            P,Q,R,S,T and U                                 (3marks)

 

 

 

 

 

  1. i) State the function of the part labeled Q.                                              (1mark)

 

 

 

  1. ii) State two adaptations of structure Q to its function.                                                   (2 marks)

 

 

 

  1. State two environmental factors which regulate the function of the part labeled P.      (2 marks)

 

 

 

 

  1. Measure the length of one cell of region labeled Q on the photomicrograph whose magnification is X5000.What is the actual length of the cell in micrometer? Show your working.         (3marks)

 

 

 

 

 

  1. You are provided with;

 Specimen  S  - Orange fruit

Specimen T – Garden pea fruit

  1. Make a transverse section through specimen S.
  2. Draw the transverse section of s and lab le any three parts.             5mks

 

 

 

 

 

 

  1. With a reasons identify the type of frit to which specimen S belong. 2mks

 

 

  1. I) Suggest the type of placentation found in specimen T. 1mk

 

ii)Name the mode of dispersal of specimen T.                                      1mk

 

 

iii)Explain two ways in which specimen T is adapted to its mode of dispersal.    2mks

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  1. Extract some juice from specimen S, using the reagent provided carryout a food test and complete the table below

Food substance

Procedure

Observations

Conclusion

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  1. Name a deficiency disease in humans that would result from lack of fruits such as S in the diet

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.You are provided with photographs of animals.  Study the photographs and the dichotomous key below to

enable you identify the taxonomic group to which each animal belongs.

 
   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

KEY:
1          (a)        Jointed legs present………………………………………..…........ go to 2

                        (b)        Jointed legs absent………………………………………………... go to 7

2          (a)        Three pairs of legs……………………………………………..…. go to 3

                        (b)        More than three pairs of legs……………………………….…….. go to 5

3          (a)        Wings Present…………………………………………………..… go to 4

                        (b)        Wings absent……………………………………………….……... Anoplura

4          (a)        One pair of wings……………………………………………….… Diptera

                        (b)       Two pairs of wings…………………………………………….….. Hymenoptera.

  1. 5. (a)       Four pairs of legs ……………………………………………..…. Archnida

                        (b)        More than ten pairs of legs……………………………………….. go to 6

6          (a)        One pair of legs in each body segment……………………………Chilopoda

                        (b)        Two pairs of legs in each body segment…………………………..Diplopoda

  1. 7. (a) Body covered by scales……………………………………………..Pisces

                        (b)        Body covered by feathers…………………………………………..Aves

  • Using the key, identify the organisms to their taxonomic groups. In each case, give the sequence of steps followed in identifying them.                 (8mks)

 

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