2016年6月2日 星期四

F4 Bio 2nd Term Test 5 Ch10

F4 Biology Test 5: Transpiration, transport and support in plants

A.     Multiple Choice (10marks)
Q.
1
2
3
4
5
6
7
8
9
10
Answer
C
C
A
D
C
D
A
B
D
C
Wrong no.











B     Conventional questions
1      a      Cut the leafy shoot under water. /
While the leafy shoot is still under water, attach it to the stopper of the bubble potometer. /
Seal off all connections with vaseline. (any 2)                                                                        1×2

        b      i       (47.8 – 5.8) × 0.05 cm3 = 2.1 cm3                                                                                   1×2
                ii      (868 – 866.3) g = 1.7 g = 1.7 cm3                                                                                   1×2
iii     (2.1 – 1.7) cm3 = 0.4 cm3                                                                                               1×2

        c      The distance would be shorter.                                                                                                1
                In darkness, the stomata are closed.                                                                                 1
                The rate of transpiration is low.                                                                                               1

2      a      Transpiration pull                                                                                                           1

b      The cell wall of cell P is thick and lignified.                                                                    1
This prevents the vessel made up of cell P from collapsing when a negative pressure is
created during transpiration.                                                                                            1
                Cell P is hollow / has no cytoplasm / nuclei / end walls.                                                  1
This offers less resistance to the transport of water.                                                         1

        c      As the transpiration pull draws water up the vessel, water is drawn into cell P from the
neighbouring cells by osmosis.                                                                                                1
                This decreases the water potential of cell Q and water moves from the neighbouring
cell R to cell Q by osmosis.                                                                                             1
As a result, a water potential gradient is set up across cells Q, R and S and water moves
inwards from cell to cell by osmosis.                                                                                       1
Finally, the water potential of cell T becomes lower than that of the water in the soil and

water in the soil enters cell T by osmosis.                                                                                1

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