F4 Biology Test 5: Transpiration, transport and support in plants
A. Multiple
Choice (10marks)
Q.
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1
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2
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3
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4
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5
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6
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7
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8
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9
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10
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Answer
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C
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C
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A
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D
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C
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D
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A
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B
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D
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C
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Wrong no.
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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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