CAMBRIDGE IGCSE™ BIOLOGY: END-OF-CHAPTER TEST 3
Exam-style questions and sample answers have been written by the authors. In examinations, the way marks are awarded may be different.
References to assessment and/or assessment preparation are the publisher's interpretation of the syllabus requirements and may not fully
reflect the approach of Cambridge Assessment International Education.
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? ü ü ü
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.
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.
Cambridge IGCSE™ Biology – Martindill © Cambridge University Press 2021 1
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
2 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]
Cambridge IGCSE™ Biology – Martindill © Cambridge University Press 2021 2
CAMBRIDGE IGCSE™ BIOLOGY: END-OF-CHAPTER TEST 3
3 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
40 86
50 100
Table 3.3
Cambridge IGCSE™ Biology – Martindill © Cambridge University Press 2021 3
CAMBRIDGE IGCSE™ BIOLOGY: END-OF-CHAPTER TEST 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.
_____
[2]
[Total: 8]
[Test total: 20]
END OF TEST
Cambridge IGCSE™ Biology – Martindill © Cambridge University Press 2021 4
