2013-DSE
BIO
lluman Physiology : Regulation and Control
SECTION A
PAPER 2
HONG KONG EXAM INAT IONS AND ASSESSMENT AUTHORITY
Answer ALL parts of the question.
HONG KONG DIPLOMA OF SECONDARY EDUCATION EXAMINAT ION 2013
l(a)
The X-ra y photograph below shows a sma ll e lectronic dev ice that has been surgically implanted into the
chest cavity of a patient sufferin g from hca11 disease. This dev ice maintains the proper rhythm of lhe
patient's heart.
PAPER 2
BIOLOGY
wire leading to the heart
heart
electronic device
11.45 am - 12.45 pm (1 hour)
This paper must be answered in English
INSTRUCTIONS
A. B, C and D in this Paper. Attempt ALL questions
(1)
There are FOUR sections,
in any TWO sections .
(2)
Write your answers in the Answer Book DSE (C) provided.
(not part of a questiOfl) on a new page.
(3)
Present your answers in paragraphs wherever appropriate.
(i)
Which structure of the heart does the device replace functionally?
(4)
Illustrate you r answers with diagrams wherever appropriate.
(i i)
(5)
The diagrams in this paper are NOT necessarily drawn to scale.
The structure mentioned in (i) triggers a seri es of events that lead to the proper funct ioning of the
heart. Describe these events.
(4 marks)
(iii)
During the cardiac cycle, there is a period of time in which both atria and ventricles are in a re laxed
state. Briefly describe the pathway of blood tlow returning from the lungs to the heart chambers
during this period.
(3 marks)
(iv)
With reference to a hormone, describe how it can bring about an increase in cardiac output.
·
(3 marks)
• .,'r• .
Start each question
l (b)
Kathy has been married for two years. In the first year, s he took a progesterone-containing contraceptive
pill. Then she stopped taking it a nd got pregnant. Three months later she noticed bleeding from her
vagina. Her doctor gave her progesterone to slop the bleeding.
( i)
Expla in how progesterone in the contracept ive pi ll prevented Kathy from becoming pregnant.
(5 marks)
(ii)
(!)
What was the possible cause and consequence of the bleeding from Kathy's vagina?
(2 marks)
(2)
How did the progesterone prescribed by the doctor help Kathy in this case?
Not to be taken away before the
end of the exam ination session
20 13-DSE-B IO 2-1
20 13-DSE-13 10 2-2
29
-
(!mark)
30
(2 marks)
SECTION B
Applied Ecology
SECTIONC
Answer ALL parts of the question .
2(a)
Answer ALL parts of the question.
An experiment was conducted to stud y the effect of ac id rain on the growth of bean seedlings planted in
The same amount of water
pots containing two different soils, either with or without heavy metal X.
with a pH of either 6 or 3 was used to water the seedlings every day and their average increase in fresh
weight was measured after 30 days. The results are shown in the table below:
I
I
Microorganisms and Humans
increase in fresh
ol-1 6
I
So il without heavy meta l X
13.0
I
Soil with heavy metal X
7.5
I
Note: Rainwater normally has a pH value of 6.
3(a)
Garden composting can effectively turn food waste into fertilizer. This is done by mixing the right amounts
of food waste with soil containing various types of active microorganisms. The graph below shows the
change in temperature inside a compost pile over I 00 days:
of bean seedlin " (")
pH 3
7.7
4.3
Phase I
80
(3 marks)
(i)
What conclusion can yo u draw from the results of the experiment?
(ii)
During the experiment, excess water that came out of the potted plants was collected and the
amount of heavy metal ion X in it was determined. The table below shows the results:
Phase II
E6o
0..
H6
,.
10
Based on this informat ion, exp lain the effect of addi ng water of pl-I
contain ing heavy metal X.
(iii)
E 40
H3
Amount of heavy metal ion X
in excess waler (arbitrary unit
20
to the seedlings in soi l
(3 marks)
State the a ir pollutants that cause acid rain and state the human health problem associated with these
(3 marks)
air pollutants.
0
0
2(b)
Give three propert ies of chemica ls that make them liab le to bioaccumu lation.
(i i)
Specimens we re collected from a site where pollutant Y was known to be discharged. The levels of
pollutant Y in sea water, sediment and some organisms collected from the site are listed in the
following table:
Seawater
Sedi ment
Clams
Birds
Fish
(3 marks)
Concentration ofoollutant Y (arbitrarv unit)
2
36
163
1557
5 19
40
60
With reference to the functional role of organisms in an ecosystem, give 011e group of organisms not
included in the above table. State the ecological significance of this group of organisms. (3 marks)
(iv)
If humans consumed fish contaminated with pollutant Y, whic h human organ wou ld have a high
concentration of this pollutant? Exp lain your answer.
(2 marks)
2013-DSE-BIO 2- 3
31
100
(i)
Describe and exp lain the changes in temperature inside the compost during Phase I and II.
(ii)
It was noted that the diversity of microorganisms decreased during Phase I of the composting. With
reference to the graph, suggest an exp lanation for this observation.
(2 marks)
(iii)
(I)
Food waste should be chopped into small pieces before they are mixed with soil.
purpose of doing this?
(2)
Adequate and continuous stirring of the food waste-soil mixture is essential for effective
composting. Explain why this is important.
(3 marks)
Based on the information in the above table, which organism is most likely the top consumer of the
food chain in the site? Explain your answer.
(3 marks)
(iii)
80
Time (day)
Pollutant Y was found in sewage discharge from industry, lead ing to bioacc umulation in organisms.
(i)
20
2013-DSE-BIO 2-4
32
(5 marks)
What is the
(I mark)
J(b)
(i)
With reference to the features of fungi , exp lain how Aspergillus niger makes use of pcct inase to
obtain nutrients from the inside of the fru it.
(4 marks)
(ii)
With reference to the action ofpectinase, suggest why fruit juice produced by using pectinase
(ii i)
(I)
has a higher yie ld, and
(2)
is more nutritious.
Answer ALL pans of the question .
4(a)
In the past, diabetic patients were treated with insulin obtained from an imal pancreases. With advances in
recombinant DNA technology, insulin is now derived from genetica ll y modified (GM) bacteria. Below
shows a possib le scheme for developing such a GM bacterium :
(I mark)
(2 marks)
Step I: Iso late the human
insulin gene and ampli fy it
by PCR.
People consuming food contam inated with microorganisms may suffer from food borne in fection or
food poisoning. Distinguish between food borne infection and food poisoning.
(2 marks)
._,
Step 3: Screen and culture
the GM ·bacteria that
produce human insulin.
Give two raw materials which are necessary in Step
gene from a DNA template.
(ii)
With reference to the immune response, explai n why insu lin from GM bacteria is used instead of
that extracted from anima l pancreas.
(4 marks)
(iii)
Explain why producing insuli n from GM bacteria is cheaper than extracting it from animal
pancreas.
(2 marks)
(iv)
To funher cut the cost of in sulin production, a GM crop which produces human insulin has recently
heen developed . However, an environmenta l group is worried that growing such GM crops may
cause genetic poll ution . Exp lain why growing the GM crops may cause genetic pollution.
(2 marks)
2013-DSE-BIO 2-6
33
Step 2: lnsen the amplified
gene
into
bacterial
plasmids which are then
introduced into bacteria.
(i)
-
20 t 3-DSE-BIO 2- 5
Biotechnology
SECTION D
Aspergillus 11iger is a llingus that spoi ls fruit. An enzyme called pectinase is sec reted from the fun gus
during its colon isation on the fruit surface . This enzyme can be used in fruit juice production.
34
for the amplification of the human insulin
(2 marks)
Marking Scheme
4(b)
The diagram below shows the DNA fingerprints of five members of a family, which consists of a couple
and three children. One of the children is from the mother's previous marriage.
Mother
Father
Child I Child 2
Child 3
This document was prepared.for markers' reference. It should not be regarded as a set of model
answers. Candidates and teachers who were not involved in the marking process are advised lo
interpret its contents with care.
Paper I
' . ·'·
SECTION A
Question No.
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Key
Key .
Question No.
I.
D (54%)
21.
D (54%)
2.
22.
A (60%)
3.
c
c
(72%)
23.
D (48%)
4.
A (81%)
24.
A (65%)
5.
c
(41%)
25.
B (24%)
6.
A
(47%)
26.
B (33%)
7.
B
(44%)
27.
B (64%)
8.
c
(42%)
28.
A (55%)
29.
(76%)
•
(i)
Based on the information
deduce wh ich child is from the mother's previous marriage.
(3 marks)
10.
D (67%)
30.
c
c
(ii)
Although the other two children are the biological children of the parents shown, their DNA
fingerprints display different patterns. Explain why this is so.
(3 marks)
11.
c
c
(35%)
3 1.
B (64%)
12.
(80%)
32.
B (47%)
The different patterns shown in the DNA fingerprinting are due to the presence of variable number
tandem repeats (VNTRs) on human chromosomes. VNTRs are short sequences of repeated DNA
on the non-coding region of chromosomes and the number of VNTRs varies greatly from person to
person . Explain why a large number of variations can exist in VNTRs but fewer variations are
(4 marks)
found in functional genes.
13.
B (84%)
33.
A (79%)
14.
A (80%)
34.
c
15.
B (47%)
35.
D (90%)
16.
D (55%)
36.
D (55%)
17.
B (71%)
18.
D (32%)
(i ii)
9.
19.
B (59%)
20.
A (78%)
(62%)
(7%)
(8 1%)
This item was deleted.
END OF PAPER
Note: Figures in brackets indicate the percentages ofcandidates choosing the correct answers.
Sources of materials used in this paper will be acknowledged in the Examination Report and Question Papers
published by the Hong Kong Examinations and Assessment Authority at a later stage.
General note on item deletion
It is normal for the HKEAA to delete a small number of items from its multiple-choice question papers if they prove
unsatisfactory. In pract ice, there are a number of reasons why this is considered necessary. By far the most common
reason for deleting an item is that the item fails to discriminate between weak and able candidates-in other words, the
majority of the candidates involved had to rely on guesswork in answering that question. lfsuch an item is retained, the
measurement process is rendered less effective . Where items have been deleted in the live papers, they are still
included in this series of publications . They are indicated as de leted items. Such items may be discussed in the
examination reports.
2013-DSE-BIO 2-7
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