Biology Paper 3 (Practical), WASSCE (PC 2ND), 2022

Question 2

  1. The diagram below are illustration of experimental setups labelled A, B, C and D used to investigate a biological process. Study them and answer questions 2(a) and 2(b).

 

(a)        State the aim of the experiment
                                                                                                                        [1 mark]          
(b)        Complete the table below using setups A, B, C and D.
           


Setup

Observation

Reason for Observation

Conclusion

 

A

 

 

 

 

B

 

 

 

 

C

 

 

 

 

D

 

 

 

 

           

 

 

[12 marks]

(c)        Outline the process of germination in a cowpea seedling.                        [5 marks]
(d)        (i)         Name the type of germination that would be observed in a cowpea seedling.
[1 mark]
(ii)        Give one reason for the answer in 2(d)(i).                                  [1 mark]
(e)        Name two food substances present in cowpea seedlings.                         [2 marks]
(f)         List three parts of a germinating cowpea seedling.                                 [3 marks]

Observation

 

Candidates’ performance was poorest in this question. Many could neither state the aim of the experimental setup, nor the process involved in a cowpea seedling. This is an indication that many of the candidates did not perform any experiments in Biology while in a school.

The expected answers are:

(a)        Aim of the experiment
To investigate conditions necessary for seed germination/to show that air/oxygen, water, suitable temperature/warmth are necessary for germination.                                                                           

(b)        Table
           


Setup

Observation

Reason for observation

Conclusion

A

No change in cowpea
seeds/seeds remain dormant/no germination

Moisture/water absent

Water is necessary for germination of seeds

B

Germination observed in cowpea seeds/seeds germinated

Water/suitable temperature/warmth viable seeds and air/oxygen present

Water, suitable temperature/warmth; viable seeds and air/oxygen are necessary for germination of seeds

C

No change in cowpea
seeds/seeds remain dormant/no germination

Air/oxygen not present/absent

air/oxygen is necessary for germination

D

No change in cowpea
seeds/seeds remain dormant/no germination

Suitable temperature not present/absent

suitable temperature is necessary for germination

 
(c)        Process of germination

  • Seeds absorb water/imbibition of water;
  • Seed swells/testa breaks;
  • Enzymes are activated;
  • Stored food is broken down/digested to release nutrients;
  • Embryo absorbs nutrients;
  • Radicle grows/bursts out and grows downwards;
  • Roots appears;
  • The hypocotyl elongates and pushes the cotyledons above the soil;
  • Plumule then grows out/epicotyl elongates to push plumule out.
  • Foliage leaves appear.

  
(d) (i)   Type of germination observed in cowpea seedlings
            Epigeal.                                                                                                                      
Note:  spellings must be correct to score.

 

     (ii)   Reason for the answer in 2(d)(i)
            Cotyledons will be carried above the soil level/hypocotyl elongates more than epicotyl.                                                                                                                                                                
(e)        Food substances present in cowpea seedling

  • Starch/carbohydrate;
  • Protein;
  • Fats and oil.                                                                                                

(f)        Parts of a germinating cowpea seedling

  • epicotyl;
  • hypocotyl;
  • plumule;
  • radicle;
  • cotyledon;
  • testa/seed coat;
  • foliage leaf;
  • tap root;
  • secondary root.