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Biology Paper 2, May/Jun 2010  
Questions:   1 2 3 4 5 6 7 8   Main
General Comments

Question 1

(a) Write the chemical equation for each of the following processes:
(i) aerobic respiration;
(ii) anaerobic respiration in plants;
(iii)anaerobic respiration in animals.[6 marks]
(b)State four functions which the liver of a patient suffering from cancer of the liver will not be able to perform, (4 marks]
(c)Make a diagram 8 - 10 ern long of a flame cell and label fully.[6 marks]

(d)Name one of appropriate hormone each responsible for the following conditions in plants
(i) ripening of fruits;
(ii) breaking dormancy in seeds;
(iii) weed control;
(iv)leaf fall [4 marks].


This was not popular question in this section and not many candidates attempted it. Those who attempted it scored poor marks.
Many candidates could not write the correct equations for aerobic and anaerobic respiration they rather defined the concepts and so lost the marks. Some candidates who attempted the equation could not balance it, most of them got the reactants correctly but could not correctly list the products ..
The expected answer was:
  (a) Chemical Equations for processes
  (i) Aerobic Respiration

      (ii)       Anaerobic respiration in plants

(Iiii) Anaerobic respiration in animals
C6H1206 -. 2CH3CH(OH)COOH + 2ATPlEnergy/150 k cal.

Most candidates who attempted this question could correctly state four functions which a cancerous liver would not perform and drew a fair diagram of the flame cell with adequate details however a number of candidates did not conform to the size specification, drew diagram with wooly lines, free-hand guidelines which were crossing. Spelling of labels wrongly also contributed to the poor performance on this question.
Most candidates could also state the hormones necessary for ripening of fruits, breaking dormancy in seeds, weed control and leaf fall but many of them could not score due to wrong spelling of hormones. Expected answers include:
Hormones responsible for
ripening of fruit - auxin/ethane/ethylene/ AA
breaking of dormancy in seeds - AuxiniGibberelins/cytokinins (kinta)
weed control- Auxin/2,4 - D/2,4 - Dichlorophenoxyacetic acid
leaf fall - Abscisic acid.

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