K.C.S.E Biology Q & A - MODEL 2008PP2QN05

K.C.S.E Biology Q & A - MODEL 2008PP2QN05

 A freshly obtained dandelion stem measuring 5 cm long was split lengthwise to obtain two similar pieces The pieces were placed in solutions of different concentrations in Petri dishes for 20 minutes.
The appearance after 20 minutes is as shown

​(a) Account for the appearance of the pieces in solutions L1 and L2
(b) State the significance of the biological process involved in the experiment 

answers

​(a) L1
Inner cells gained water by Osmosis; hence increased in length; epidermal cells did not gain water because they are covered by a water proof cuticle leading to currature.
L2
Inner cells lost water by osmosis; leading to (flaccidity) decrease in  length; epidermal cells did not  lose water due to waterproof  leading to  currature

(b)
Support in (herbaceous) plants
Absorption of water
Opening and closing of stomata
Movement of water from cell to cell
Leading in infectious plants
Folding of leaves in the Mimosa