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Question 1
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- Study carefully specimens A,B,C, and D
Copy and complete the table below.
Specimen |
Part modified to form specimen |
Mode of propagation |
Stored Material |
A |
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B |
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C |
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D |
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- In a tabular form state four observable differences between specimen A and C. (4 marks )
- Crush a small portion of specimen D and divide it into three equal parts.
- Place a portion on a white tile and add two (2) drops of iodine solution.
- Place another portion in a test tube and add one (1)ml of distilled water and shake.
Add a few drops of sodium hydroxide (NaOH) solution and shake again. Slowly add a few drops of 1% copper sulphate solution.
- Smear the third part on a filter paper, leave for about five (5) minutes and observe carefully.
Record your results in 1(c)(i),(ii) and (iii) above as shown in the table below.
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Test |
Observation |
Inference |
(i) |
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(ii) |
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(iii) |
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(9marks )
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This question was the less popular question in this section and candidates who attempted the question did not do so well. In the column in part modified to form specimen many candidates wrote the name of the specimens namely A. Cactus, B-Onion, C- Ginger, D-Carrot rather than stem, shoot the root and so lost the score. They also could not state the mode of propagation of plant e.g. via stem, bulb, rhizome and root tuber/seed respectively but most candidates could however state the food materials stored in each of the specimens and scored the full marks. In answering question (b) many candidates could properly state the differences between specimens A/Cactus and C/ginger and scored fair marks. A large number of candidates however, performed poorly in question 1(c). The question required the candidates to carry out the food tests, observe the reactions and draw inferences. Most candidates could not record the tests properly and so failed to record proper observations and draw proper inferences.
Some candidates seemed to be using theoretical knowledge as they stated positive observations where the observations should have been negative. Expected answers include:
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Test/Correctly recorded |
Observation |
Inference |
(i) |
Portion of D and two drops of iodine solution |
Blue-black colour formed/obtained |
Presence of starch |
(ii) |
Portion of D plus 1ml of water, add a few drops of sodium hydroxide/water solution and 1% copper sulphate solution |
No colour change/blue colour retained |
Protein absent |
(iii) |
Crush and smear a portion of D on a filter paper and leavefor five (5)mins |
Paper stained orange |
Fat absent. |
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