CAMBRIDGE IGCSE™ BIOLOGY: END-OF-CHAPTER TEST 3
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Name Date
End-of-chapter 3 test
Diffusion, osmosis and active transport are the three main methods by which
substances enter and
leave cells.
1 Complete Table 3.1 to compare the processes by which substances move into
and out
of cells.
Diffusion Osmosis Active transport
Does it involve random movements of particles?
Does a partially permeable membrane have to
be present?
Does it involve particles moving down their
concentration gradient?
Does it involve particles moving up their
concentration gradient?
Does the cell use energy to make it happen?
Table 3.1
[3]
A student decided to investigate osmosis using yam tissue. Yams are root
vegetables similar to potatoes and cassavas. He wanted to find out about the effect
of different concentrations of
glucose solution.
The student cut five rectangular blocks of yam of the same size and placed them in
test-tubes labelled V, W, X, Y and Z. The mass of each block was measured and
recorded in Table 3.2.
Next, the student prepared five identical volumes of glucose solutions of different
concentrations and added them to the separate test-tubes containing the yam
blocks. These were 10%, 20%, 30%, 40% and 50% concentration.
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CAMBRIDGE IGCSE™ BIOLOGY: END-OF-CHAPTER TEST 3
The yam blocks were left in the solutions for one hour. After this, they were
removed and carefully blotted dry. The mass of each was then measured again and
recorded in Table 3.2.
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CAMBRIDGE IGCSE™ BIOLOGY: END-OF-CHAPTER TEST 3
Concentration of Mass of yam block at Mass of yam block
Yam strip Change in mass / g
glucose solution / % start / g after 1 hour / g
V 10 5.0 5.5
W 20 5.0 5.2
X 30 5.0 4.9
Y 40 5.0 4.6
Z 50 5.0 4.2
Table 3.2
1 Use the information provided to answer the following questions.
a Complete Table 3.2 by calculating the change in mass for each yam block. [1]
b Suggest explanations for the change in mass recorded for yam blocks V and Z.
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________ [3]
c Suggest why each block was blotted dry before its mass after one hour was
measured.
__________________________________________________________________________
__________________________________________________________________________ [2]
d Explain why all the blocks of yam were cut to the same size at the start of this
investigation.
__________________________________________________________________________
__________________________________________________________________________ [2]
e The student was given 20 cm3 of a glucose solution of concentration 40%.
Describe how
he could use this solution to prepare 40 cm3 of a glucose solution of
concentration 20%.
__________________________________________________________________________
__________________________________________________________________________ [1]
[Total: 9]
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CAMBRIDGE IGCSE™ BIOLOGY: END-OF-CHAPTER TEST 3
2 When plant cells lose water, the volume of cytoplasm reduces and the cell
membrane moves away from the cell wall. When this happens, the cells are
said to be plasmolysed.
Figure 3.1 is a diagram that represents a group of plant cells, some of which are
plasmolysed.
Figure 3.1
a Calculate the number of plasmolysed cells as a percentage of the total
number of cells in
the diagram. Show your working and give your answer to the nearest whole
number.
[2]
b A student carried out an investigation into the relationship between the
concentration of glucose solution and the number of plant cells which were
plasmolysed. She placed blocks of yam in glucose solutions of different
concentration and counted the number of cells that were plasmolysed. She
then calculated the percentage of cells that were plasmolysed in each
solution. Her results are shown in Table 3.3.
Concentration of glucose solution / % Percentage of cells that were plasmolysed
10 0
20 9
30 23
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CAMBRIDGE IGCSE™ BIOLOGY: END-OF-CHAPTER TEST 3
40 86
50 100
Table 3.3
i Plot a line graph of the results in Table 3.3. Join the points on your graph
with ruled,
straight lines.
[4]
ii Use your graph to estimate the concentration of glucose solution in which
50% of the
yam cells would be plasmolysed. On your graph, show how you obtained
this value.
_____
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CAMBRIDGE IGCSE™ BIOLOGY: END-OF-CHAPTER TEST 3
[2]
[Total: 8]
[Test total: 20]
END OF TEST
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