Microscopy and Magnification
Q1.
The image below shows part of a root from a cress plant.
 
(a)     What type of microscope was used to create the image above?
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(1)
(b)     The magnification of the cress root in the image above is × 200.
There are 1000 micrometres (μm) in a millimetre (mm).
Calculate the real length of the root hair, X.
Give your answer in micrometres (μm).
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Real length X = ____________________ μm
(2)
(c)     Root hair cells take up water from the soil.
Explain one way in which the root hair cell is adapted to this function.
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(2)
The table shows the water uptake by a plant’s roots on two different days.
 
 	Mean water uptake in cm3 per hour	
Cold day	1.8	
Hot day	3.4	
(d)     Explain why the mean rate of water uptake is higher on a hot day than on a cold day.
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(3)
(e)     The concentration of mineral ions in the soil is lower than in root hair cells.
Root hair cells take up mineral ions from the soil.
Root hair cells contain mitochondria.
Explain why root hair cells contain mitochondria.
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(4)
(Total 12 marks)