Po Leung Kuk Celine Ho Yam Tong College
Form Five Biology Unit Exercise (1)
Chapter 23 – Infectious diseases and disease prevention
Name: _________________ Class: __________(
)
22
4⽇
Jogephfilhtln
Marks: _________/35
Section A: Multiple choice questions (10 marks)
Instruction: Please write your MC answer in the following box. Circle the answer will not be graded.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
1
2
3
4
C A CB A AX v x.VE
Which of the following statements about pathogens is correct?
A All pathogens multiply inside the human body.
B All pathogens are infective.
C All pathogens are microscopic.
D All pathogens obtain nutrients from the host.
Most patients suffering from malaria run a fever every two or three days, depending on the Plasmodium
species that causes the disease. Which of the following is the most likely explanation for this cyclical
fever pattern in malaria patients?
A The patients are bitten by mosquitoes at intervals.
B Plasmodium multiplies in the liver cells of the patients at intervals.
C Plasmodium multiplies in the red blood cells of the patients at intervals.
D Red blood cells burst and release newly formed Plasmodium and toxins at intervals.
Which of the following statements about measles are correct?
(1) It can be transmitted by air.
(2) Avoid going to crowded places is a way of preventing it.
(3) It can be treated by sulpha drugs.
A (1) and (2) only
B (1) and (3) only
C (2) and (3) only
D (1), (2) and (3)
The electron micrograph below shows the
pathogen causing Middle East Respiratory
Syndrome (MERS).
Which of the following statements about the
-
labelled structures is/are correct?
(1) X will be introduced into the host cell.
(2) Y is responsible for damaging the cell
membrane of the host cell.
(3) Z protects the pathogen against the action of
antibiotics.
A (1) only ˇ
B (3) only
C (1) and (2) only
D (2) and (3) only x
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5
Which of the following combinations correctly states the type of pathogen causing the infectious
disease?
Infectious disease
Type of pathogen
A AIDS
fungi
B cholera
protist x
C dengue fever
virus
.
D malaria
bacteria
7 Protists *
i
⼆
Directions:
Questions 6 and 7 refer to the diagram below, which shows the growth of four bacteria (W, X,
Y and Z) on an agar plate with a strip of fungus growing on it before and after the plate was
incubated at 30 ºC for 48 hours.
_
Y
W
W
Y
X
Z
incubation
plating
patterns of
bacteria
X
Z
a strip
of fungus
6
Arrange the four bacteria in ascending order of degree of susceptibility to the antibiotic produced by the
fungus.
A W, X, Y, Z
B Y, X, W, Z
C Z, W, X, Y
D Z, Y, X, W
7
If the antibiotic produced by the fungus is used indiscriminately as a medicine to inhibit the growth of
bacterium Y, which of the following is the expected result when the experiment is repeated a few years
later?
A The bacterial strip of Y grows further away from the fungal strip.
B The bacterial strip of Y grows next to the fungal strip.
ˇ
C The bacterial strip of Y remains the same.
D No bacterial strip of Y is observed.
_
_
8
Which of the following are possible actions to slow down the development of antibiotic resistance in
bacteria?
(1) patients follow advice given by the doctor when taking antibiotics
(2) do not share antibiotics with others
(3) maintain good personal hygiene
X
A (1) and (2) only
B (1) and (3) only
C (2) and (3) only
D (1), (2) and (3)
_
_
⼀⼀
v
_
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The graph below shows the amount of an antibiotic used and changes in the proportion of resistant
bacteria in a bacterial population over a period of time in a hospital.
-
amount of antibiotic used /
proportion of resistant bacteria
in the bacterial population
(arbitrary unit)
9
Key:
100
amount of antibiotic
used
80
0
60
proportion of resistant
⼀
bacteria in the
bacterial population
上
40
20
0
0
1
2
3
4
5
6
7
8
year since the usage of the antibiotic
Which of the following is/are the possible explanation(s) for the decreased use of the antibiotic after
two years?
(1) A lower dosage of the antibiotic was sufficient to✓
kill the bacteria.
(2) The antibiotic became less effective against the bacteria.
(3) A decreased use of the antibiotic would allow resistant bacteria to mutate back into non-resistant
bacteria.X
A (1) only
B (2) only
C (1) and (3) only
X
D (2) and (3) only
10
Yellow fever is a mosquito-borne disease prevalent in tropical areas of Africa and Central and South
America. If a person plans to travel to these areas, which of the following should he/she do to reduce
the transmission
of the disease?
(1) receiving a vaccine against yellow fever before the trip
(2) wearing light-coloured and long-sleeved tops and trousers during theˇ
trip
(3) using insect repellent for some time ox
after the trip
A (1) and (2) only 。
B (1) and (3) only
C (2) and (3) only
D (1), (2) and (3)
ˇ
Section B: Structured question (25 marks)
1
M.MN "
_
The diagram below shows the transmission cycle of Japanese encephalitis. The arrows in it represent
the passage of Japanese encephalitis virus (JEV) between the animals. The virus concentration in pigs
_
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is much higher than that in birds, thus humans usually infect Japanese encephalitis from cycle II.
-
pig
o
bird
⼦
cycle I
mosquito
cycle II
mosquito
→
mosquito
human
t
a
bird
pig
(in rice fields)
(in pig farms)
,
Describe how JEV in birds eventually passes to humans.
(3 marks)
Moyuiuaavethevewrurryingthevivmto
t.uenirdwhentheyreted.Utnermoyuiloetwillhite.tn
enirdandcnrrytuevirustothepigswhentneyveted.li
thevmvyuituenwillnitethepigsundurrytnevirm
b
tuhumanshyhiting
Suggest one measure to reduce the passage of JEV in cycle I and cycle II respectively.
C
_
i
marks)
=
_
(2
_
I.tarmenunuprnypentiiidestotnerivetieldtouillt.nl
mvnquitnandtnelarvue.Inyhierndiute.int
Inugue
htaynnntwnterareainpigtnrmstopreventnreedingutmv yuitoe
ii
Gpfiíliùdenneartnetavmtvpreventtnemouquitoesentering
Suggest one method to prevent JEV in cycle I from entering cycle II.
(1 mark)
t.net nrmwhitlùlltheirlnrvne
2
,
nǎligntwlmveduhǖand
iii
Suggest two measures for humans to avoid contact with mosquitoes.
(2 marks)
c
It is not possible for JEV to be transmitted from one person to another. Give a possible reason for
this.
(1 mark)
longeTveduothei.AM
gimeurepeuenuonu nes.Im n itywilprvdu .in
tnlhumanhudy.co
Cholera is an infectious disease caused by the bacterium Vibrio cholerae. A scientist collected V.
cholerae from a cholera patient and carried out an experiment to study the effectiveness of four
antibiotics (W, X, Y and Z) against the bacterium. In the experiment, agar plates containing different
concentrations of each of the four antibiotics were prepared. Then a sample of V. cholerae was spread
-
_
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evenly onto each agar plate. The plates were incubated at 30 ºC for 48 hours. After incubation, the
number of colonies of V. cholerae on each plate was counted and recorded in the bar chart below.
a
b
i.Hywaterandtwd.patientautneunmature.tw
State one possible way by which the patient contracted cholera, and briefly describe how V.
cholerae causes the disease.
(2 marks)
ddireuyand
tnehu eriamultifnintheirhvdy.mtiniotn.me
With reference to the bar chart, which of the four antibiotics would be the most suitable one to
treat cholera? Explain your answer.
(4 marks)
ttdiantiniotiuununlthlhauriaevenat
www.nuntration.tromtneuavt.Ulunntiniutncanwill
innuwytnattneantinitioi
thev.mneranuuerinumpleuy.in
uuinninittneuyntheuiofpvoteinandǐnuueivauidsiu
huinaueriaullninthlirhudydevelopanantinivtivrenintauce.in
leviuuntyvowaudunniimlreproduu.int
nuuevia.int
c
In some cholera patients, prescription of antibiotics may not be able to treat all cholera symptoms.
Give three possible reasons for this.
(3 marks)
echoleranauaiamutateandheumereniutant.tv theantihiot.in
Epidemihruinnotwoavarytrumqennum
d
.
In countries with high risks of cholera, vaccines may be given to the public for disease prevention.
Suggest how vaccines can protect the health of the whole community.
(2 marks)
_
_
Vauinunāppeoplldevdopimmunitg
tutnehaueriuofvirm.int
hodyullnunnerentanlutnenuwaia
5/6
。
3
A scientist carried out an investigation to study the possibility of three new antibiotics
(P, Q and R) for treating a certain disease. He recruited some patients and divided them into four
groups. One group received no antibiotics and the other three groups each received a different
antibiotic. After the course of antibiotic treatment, the average number of bacteria left in the body of
patients of each group was measured. The table below shows the results.
o-tineglwegmaylltlrlmaini.tn
⼀
⼀
Group of patients
Receiving no antibiotics
Receiving antibiotic P
Receiving antibiotic Q
Receiving antibiotic R
a
Average number of bacteria left in the
body after treatment
100 000
2510
20
400
The scientist used a new pair of gloves between collecting bacterial samples from different groups
of patients. Explain the importance of this.
(2 marks)
aueriasutunttuemmnerot
nnvlerininothernodyotpatieuuwillhlditterent.mu
b
uwuteandvlliahllveuultunneull tldituituewgwves.in
Based on the results, the scientist suggested that it was better to use a combination of any two of
the antibiotics investigated instead of using only one of them for the treatment of the disease.
Explain the biological principle behind.
(3 marks)
iunawunanduillawidevnngeotnuueriaetteuivey.in
evemaneuerunnuutaiminntinytuepatnugenil
nuuevia.in
iymetnudignyuninghrud-tpevtrumuutihit.in
End
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