CAMBRIDGE IGCSE™ BIOLOGY: END-OF-CHAPTER TEST 10
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Name Date
End-of-chapter 10 test
1 The lists below show seven terms and seven descriptions.
Draw a line from each term to its description. One has been done for you.
Term Description
A molecule on the surface of a cell or virus that
phagocyte
is recognised as foreign by white blood cells
Resistance to a pathogen as a result of having
lymphocyte
antibodies provided by another organism
Proteins secreted by lymphocytes in response
pathogen
to the presence of an antigen
Resistance to a pathogen as a result of making
antigen
your own antibodies
antibodies A white blood cell that secretes antibodies
passive immunity An organism or virus that causes disease
A white blood cell that ingests and
active immunity
digests bacteria
[6]
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CAMBRIDGE IGCSE™ BIOLOGY: END-OF-CHAPTER TEST 10
1 Much of our understanding of disease and immunity has been learned from
experiments that involved special ‘swan neck’ flasks containing nutrient broth
solution to investigate the growth of microorganisms (Figure 10.1).
Figure 10.1
a The fresh broth was boiled in the flasks at the beginning of the experiment.
Suggest why.
_________________________________________________________________________ [1]
b Describe and explain the results of this experiment.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________ [3]
[Total: 4]
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CAMBRIDGE IGCSE™ BIOLOGY: END-OF-CHAPTER TEST 10
2 The experiments described in question 2 helped to develop the modern aseptic
techniques we now use to grow bacteria in the laboratory. Figure 10.2 shows
the results of two different methods that can be used to test the effectiveness
of medicinal substances that kill bacteria.
Figure 10.2
a Describe method A in Figure 10.2 and how it could be used to compare the
effectiveness of the four different substances: P, Q, R and S.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________ [4]
b Method B in Figure 10.2 involves following these steps:
The antibiotic to be tested is added to a known volume of broth.
A known quantity of bacteria is added to the broth, which is then
incubated.
After incubation, a small drop of broth is placed onto a tiny grid drawn onto
a
microscope slide.
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CAMBRIDGE IGCSE™ BIOLOGY: END-OF-CHAPTER TEST 10
The number of bacterial cells found in one field of view are counted under
a
light microscope.
In an investigation using method B, a microbiologist inoculated 1 × 104 mm3 of
broth with
10 000 bacterial cells.
He then incubated the solution for one hour.
The grid in Figure 10.2 shows how many bacteria were found in 1 mm3 of the
nutrient broth
solution after incubation.
Using this information, calculate the mean division time of the bacteria in this
investigation.
Give your answer in minutes.
____________ minutes
[3]
c Use the image of bacterial cells on the grid in Figure 10.2 to calculate the
actual size of
a bacterial cell.
Give your answer in micrometres (m).
________ m
[2]
d Explain why it was not necessary for the scientist to use an electron
microscope in method B in Figure 10.2.
_________________________________________________________________________
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CAMBRIDGE IGCSE™ BIOLOGY: END-OF-CHAPTER TEST 10
_________________________________________________________________________ [1]
[Total: 10]
[Test total: 20]
END OF TEST
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