K.C.S.E Biology Q & A - MODEL 2010PP2QN01

K.C.S.E Biology Q & A - MODEL 2010PP2QN01

In an experiment, disinfected soaked bean seeds were put in a vacuum flask which was then fitted with a thermometer as shown in the diagram below.

The temperature readings were taken every morning for three consecutive days.
(a) Which process was being investigated? 
(b) (i) What were the expected results? 
(ii) Account for the answer in (b)(i) above, 
(c) Why were the seeds disinfected? 
(d) Why was a vacuum flask used in the set-up? 
(e) How would a control for this experiment be set? 

answers

(a) Respiration; 
(b) (i) Increase/rise in thermometer reading/temperature; 
(ii) Carbohydrates/starch/glucose in germinating seeds is broken down/oxidised to get energy; some of the energy is released as heat; (which increases temperature reading). 
(c) To kill bacteria/fungi/microorganisms; that would cause decay/decomposition/respiration of the beans; 
(d) To conserve heat/prevent heat loss to surroundings; 
(e) Use similar set-up but with dead and disinfected beans seeds/ use dead disinfected bean seeds/use dry bean seeds;