New Senior Secondary
MASTERING BIOLOGY
(Second Edition)
DSE
BIO
Mock Exam I
PAPER 1A
BIOLOGY PAPER 1
HKDSE MOCK EXAM I
Time allowed: 2 hours 30 minutes
This paper must be answered in English
GENERAL INSTRUCTIONS
1
There are TWO sections, A and B, in this Paper. You are advised to finish Section A in about 35 minutes.
2
Section A consists of multiple-choice questions in this question paper. Section B contains conventional
questions printed separately in Question-Answer Book B.
3
Answers to Section A should be marked on the Multiple-choice Answer Sheet while answers to Section B
should be written in the spaces provided in Question-Answer Book B. The Answer Sheet for Section A and
the Question-Answer Book B for Section B will be collected separately at the end of the examination.
INSTRUCTIONS FOR SECTION A (MULTIPLE-CHOICE QUESTIONS)
1
Read carefully the instructions on the Answer Sheet. After the announcement of the start of the examination,
you should first stick a barcode label and insert the information required in the spaces provided. No extra time
will be given for sticking on the barcode label after the ‘Time is up’ announcement.
2
When told to open this book, you should check that all the questions are there. Look for the words ‘END OF
SECTION A’ after the last question.
3
All questions carry equal marks.
4
ANSWER ALL QUESTIONS. You are advised to use an HB pencil to mark all the answers on the Answer
Sheet, so that wrong marks can be completely erased with a clean rubber. You must mark the answers clearly;
otherwise you will lose marks if the answers cannot be captured.
5
You should mark only ONE answer for each question. If you mark more than one answer, you will receive
NO MARKS for that question.
6
No marks will be deducted for wrong answers.
Not to be taken away before the
end of the examination session
New Senior Secondary Mastering Biology (Second Edition)
Mock Exam I Biology Paper 1 Section A
ã Oxford University Press 2014
- 1 -
There are 36 questions in this section.
The diagrams in this section are NOT necessarily drawn to scale.
1
Which of the following organelles may be present in prokaryotic cells?
A
B
C
D
2
3
Which of the following statements about enzyme inhibition is/are correct?
(1)
(2)
(3)
In competitive inhibition, the inhibitor binds to the active site of the enzyme.
In non-competitive inhibition, the inhibitor binds to the substrate molecules.
If the enzyme inhibition is irreversible, when a poison binds to the enzyme, the enzyme can
never work again.
A
B
C
D
(1) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
A student carries out an experiment to test the activity of a certain enzyme. Which would probably
not result in an increase in the enzyme’s activity?
A
B
C
D
4
Bringing the temperature of the experimental set-up from 20°C to 40°C.
Adding more substrates but not enzyme.
Adding more enzymes but not substrate.
Placing the substrate and enzyme in a container with double capacity.
Which of the following shows the route of blood in one complete circulation around the body,
starting from the leg?
A
B
C
D
5
cell membrane and ribosomes
cell wall and mitochondria
endoplasmic reticulum and ribosomes
nuclear membrane and DNA
leg → heart → lungs → heart → leg
leg → lungs → heart → kidneys → leg
leg → lungs → heart → intestines → leg
leg → heart → lungs → kidneys → leg
When a flowering plant is at the compensation point,
A
B
C
D
it does not need oxygen for cellular respiration.
it does not produce carbon dioxide during cellular respiration.
the amount of oxygen used for respiration is just equal to the amount of carbon dioxide
produced from photosynthesis.
the rate of photosynthesis is just equal to that of respiration.
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Mock Exam I Biology Paper 1 Section A
ã Oxford University Press 2014
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Directions:
6
Which country/countries do the children in the photograph below most probably come from?
A
B
C
D
7
Questions 6 and 7 refer to the diagram below which shows the consumption of different
types of food in three countries in grammes per head per day.
country X
country Y
country Z
can be any one of the three countries
Which country has the highest energy intake per head per day?
A
B
C
D
country X
country Y
country Z
cannot be determined from the graph
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Mock Exam I Biology Paper 1 Section A
ã Oxford University Press 2014
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8
The photograph below shows the transverse section of the human lungs under a high-power
microscope.
Based on the information shown in the photograph, which of the following statements correctly
explain why the human lungs can carry out gas exchange efficiently?
9
(1)
(2)
(3)
The distance of gas diffusion is short.
The air sacs provide a large surface area for gas exchange.
The oxygen which enters the lungs can be carried away rapidly.
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
The graph below shows how the amounts of some gases change when a person breathes through an
airtight bag.
Which curve does not show the change in the amount of the gas correctly?
A
B
C
D
curve 1
curve 2
curve 3
curve 4
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Mock Exam I Biology Paper 1 Section A
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10
The diagram below shows two experimental set-ups, A and B. Both set-ups are left in bright light
for two hours.
Set-up A
Set-up B
A student uses a piece of dry cobalt chloride paper to touch the inner wall of both bell jars. The test
paper turns pink for set-up A and remains blue for set-up B. What conclusion can be drawn from
this experiment?
A
B
C
D
11
Transpiration takes place through the leaves.
Transpiration takes place through the stem and the leaves.
Transpiration takes place through the stomata of the stem and leaves.
Transpiration takes place through the lenticels of the stem and stomata of the leaves.
In the diagram below, stages a to d indicate two successive cell cycles.
a
b
c
Which of the following statements is incorrect?
A
B
C
D
12
Stages a and b belong to the same cell cycle.
Stages b and c belong to the same cell cycle.
The quantity of DNA doubles at the end of stage c.
Even distribution of genetic material occurs at stage d.
In the regulation of blood glucose level, insulin acts as
(1)
(2)
(3)
a homeostatic regulator.
an effector.
a messenger sent from the regulator to the effector.
A
B
C
D
(1) only
(3) only
(1) and (2) only
(1) and (3) only
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d
13
The hearing ability gradually decreases as a person gets older because
A
B
C
D
14
the auditory nerve gradually degenerates.
more sensory cells in the cochlea are broken down.
the ear bones gradually degenerate.
the ear drum gradually hardens.
The graph below shows the change in body temperature of a woman in a menstrual cycle.
Which of the following events occurs on day 15 as shown in the graph?
A
B
C
D
15
start of menstruation
end of menstruation
ovulation
fertilization
Some British scientists studied the smoking habits of British women aged 25 and over. They
recorded the number of cases of lung cancer occurring over a period of eight years. Some
American scientists did a similar study on men aged 50–69. The results are shown in the graph
below:
What conclusion can be deduced from the data in the graph?
A
B
C
D
Smoking cigarette can cause lung cancer.
Women are more likely to get lung cancer than men.
Older people are less likely to get lung cancer.
The more cigarettes a person smokes, the more likely the person is to get lung cancer.
New Senior Secondary Mastering Biology (Second Edition)
Mock Exam I Biology Paper 1 Section A
ã Oxford University Press 2014
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Directions:
16
Which of the following statements about the reflex arc is incorrect?
A
B
C
D
17
1 is a motor nerve.
2 is a synapse in the CNS.
M is an effector.
S is a receptor.
Which of the following statements about the structures in the location labelled 2 is/are correct?
(1)
18
Questions 16 and 17 refer to the diagram below which shows a reflex arc in the spinal
cord.
(2)
(3)
Chemical messenger is released from the structure at the upper part to the structure at the
lower part but not vice versa.
The structures ensure a unidirectional transmission of nerve impulses.
Only the axon of one neurone can communicate with another neurone.
A
C
(1) and (2) only
(2) and (3) only
B
D
(1) and (3) only
(1), (2) and (3)
In garden pea, the production of the purple pigment in flowers is controlled by two dominant genes,
B and D, as shown in the diagram below:
gene B
gene D
enzyme B
enzyme D
substance X
(white)
substance Y
(blue)
purple pigment
(purple)
Which of the following statements is correct?
A
B
C
D
A cross between two pea plants of genotypes Bbdd and bbDd respectively produces offspring
with a phenotypic ratio of 1 : 1 : 1 : 1.
The plant of genotype bbDd produces blue flowers.
Only plants of genotype BBDD can produce purple flowers.
A plant of genotype Bbdd is self-crossed. White-flowered and blue-flowered offspring in the
ratio of 2 : 1 are produced.
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ã Oxford University Press 2014
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19
20
The fossil record is usually incomplete because
(1)
(2)
(3)
not all fossils have been found.
some fossils are broken down into very fine pieces.
some life forms left no fossils.
A
C
(1) only
(2) and (3) only
B
D
(3) only
(1), (2) and (3)
In a food web,
A
B
C
D
each type of animals can only feed on one other type of organisms.
each type of animals feed on many other types of organisms.
some animals occupy a certain trophic level in two or more food chains.
some animals occupy two or more trophic levels in a food chain.
21 Assume that 10% of the energy is transferred from one trophic level to the next. In which of the
following food chains/webs does the hawk obtain the largest amount of energy?
A
grass
B
grass
bird
rat
rabbit
hawk
insect
bird
hawk
rat
22
C
grass
insect
frog
snake
D
grass
insect
frog
hawk
Some antibiotics act by inhibiting the formation of bacterial cell walls. How does this kill the
bacteria?
A
B
C
D
23
hawk
The bacteria cannot carry out cell division.
The bacteria cannot carry out protein synthesis.
The bacteria burst when they divide.
The cell contents of the bacteria leak out.
Disease is a response to
(1)
(2)
(3)
environmental factors.
specific infective agents.
inherent defects of the body.
A
B
C
D
(2) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
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24
When an anion X is added into the culture solution in which some maize seedlings are growing,
anion X is found to be actively absorbed by the root cells of the seedlings. At the same time, active
absorption of chloride ions decreases but active absorption of potassium ions is not affected. A
possible reason is that
A
B
C
D
25
anion X inhibits ATP production in the root cells.
anion X inhibits active transport of the root cells
anion X inhibits respiration of the root cells.
anion X and chloride ions share the same kind of carrier proteins.
The diagram shows the transverse section of a lemon.
tissue X
tissue Y
The cells of tissue X differ from the cells of tissue Y in that
A
B
C
D
26
they are haploid.
they are diploid.
the genes they contain are derived from the mother plant only.
they contain genes derived from both parents.
The photograph below shows a flower commonly found in Hong Kong.
structure X
Structure X produces a sticky and sugary liquid. What are the functions of this liquid?
(1)
(2)
(3)
attracts insects
sticks pollen grains
induces the germination of pollen grains
A
C
(1) and (2) only
(2) and (3) only
B
D
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Mock Exam I Biology Paper 1 Section A
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(1) and (3) only
(1), (2) and (3)
27
A man moves his foot upwards as shown in the diagram below.
What are the states of muscles X and Y in this action?
A
B
C
D
28
Muscle X
contracting
contracting
relaxing
relaxing
Muscle Y
contracting
relaxing
relaxing
contracting
A man stands on the tip of his sole as shown in the diagram below.
Which type of lever system matches the mechanics of this part of the leg?
A
B
E
E
F
F
L
C
E
L
29
L
D
F
E
F
L
A scientist used carbon dioxide labelled with radioactive 14C to trace the path of the carbon atoms
in photosynthesis. Which of the following paths is correct?
A
B
C
D
carbon dioxide → chlorophyll → ATP
carbon dioxide → ethanol → glucose
carbon dioxide → 3-C compound → glucose
carbon dioxide → 5-C compound → 3-C compound
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30
The table below shows the relative sizes of head and body at different ages in humans.
Age
0 (at birth)
6
14
21
1:4
1: 5
1:7
1:9
Head size : body size
The data in the table show that
A
B
C
D
31
Which of the following statements about ATP is correct?
A
B
C
D
32
the head is not growing.
growth stops at the age of 21.
different body parts grow at different rates.
humans enter puberty at the age of 14.
ATP is a storage form of energy in the human body.
All the energy required in the human body comes from hydrolysis of ATP.
ATP is the only high-energy compound that supplies energy to the human body directly.
The energy stored in ATP ultimately comes from sunlight.
In an experiment, yeast cells were ground with distilled water. After centrifugation, two portions
were separated. The supernatant contains cytoplasmic matrix and the precipitate contains
mitochondria. Three test tubes, A, B and C were prepared as shown below:
Test tube
Portion of ground yeast suspension
Glucose solution
A
Supernatant
P
B
Precipitate
P
C
Whole suspension without centrifugation
P
The three test tubes were kept at 35oC in air-free conditions. After two days, which of the
following would happen?
A
B
C
D
33
No reaction would occur in test tube B.
Carbon dioxide and water would be the end products in test tube A.
Large quantity of ATP would be produced in test tube C.
No carbon dioxide would be produced in test tube C.
Which of the comparisons between the two types of diabetes mellitus is incorrect?
A
B
C
D
Type 1 diabetes mellitus
occurs less frequently in Hong Kong
usually develops in children and
young adults
can be treated by insulin injection
due to the inability of the pancreas to
produce enough insulin
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Type 2 diabetes mellitus
occurs more frequently in Hong Kong
usually develops in adults and obese
children
cannot be treated by insulin injection
due to the inability of body cells to
respond to the insulin produced
34
35
36
Malignant tumours are more dangerous than benign tumours because malignant tumours
(1)
(2)
(3)
(4)
grow continuously without control.
release toxic materials that are harmful to the body.
spread to other parts of the body through the bloodstream and lymphatic system.
invade and damage any body tissues.
A
B
C
D
(1) and (2) only
(3) and (4) only
(1), (2) and (4) only
(2), (3) and (4) only
In the defence mechanism of the human body, antigens
(1)
(2)
(3)
(4)
must be foreign to the body.
are always protein in nature.
are capable of inducing the production of antibodies.
can combine with specific antibodies.
A
B
C
D
(1) and (2) only
(3) and (4) only
(1), (2) and (4) only
(2), (3) and (4) only
What would happen as a result of several populations of a species being geographically isolated?
(1)
(2)
(3)
(4)
Inheritable variations would be produced in the species.
The species would evolve in a definite direction.
Gene flow could not occur between the isolated populations.
The isolated populations would evolve in different directions.
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (4) only
(3) and (4) only
– END OF SECTION A –
Go on to Question-Answer Book B for questions in Section B.
New Senior Secondary Mastering Biology (Second Edition)
Mock Exam I Biology Paper 1 Section A
ã Oxford University Press 2014
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Biology Paper 1 Section A
New Senior Secondary Mastering Biology (Second Edition)
Mock Exam I Biology Paper 1 Section A
ã Oxford University Press 2014
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DSE
BIO
Mock Exam I
B
Please stick the barcode label here.
PAPER 1B
New Senior Secondary
MASTERING BIOLOGY
(Second Edition)
Candidate Number
BIOLOGY PAPER 1
HKDSE MOCK EXAM I
SECTION B: Question-Answer Book B
This paper must be answered in English
INSTRUCTIONS FOR SECTION B
1
After the announcement of the start of the examination, you
should first write your Candidate Number in the space
provided on Page 14 and stick barcode labels in the spaces
provided on Pages 14, 16, 18, 20, 22, 24, 26, 28, 30 and 32.
2
Refer to the general instructions on the cover of the Question
Paper for Section A.
3
Answer ALL questions.
4
Write your answers in the spaces provided in this
Question-Answer Book. Do not write in the margins. Answers
written in the margins will not be marked.
5
Supplementary answer sheets will be supplied on request.
Write your Candidate Number, mark the question number box
and stick a barcode label on each sheet, and fasten them with
string INSIDE this Question-Answer Book.
6
Present your answers in paragraphs wherever appropriate.
7
The diagrams in this section are NOT necessarily drawn to
scale.
8
No extra time will be given to candidates for sticking on the
barcode labels or filling in the question number boxes after the
‘Time is up’ announcement.
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SECTION B
Answer ALL questions. Put your answers in the spaces provided.
The diagram below shows the arrangement of phospholipids in a cell membrane.
Describe the characteristics of phospholipid molecules that result in this arrangement.
(2 marks)
2
Complete the following paragraph with suitable words.
(3 marks)
In our body, many reactions take place at temperatures far lower than those required for
the same reactions in the laboratory. The rate of such chemical reactions are speeded up
by molecules called a
. These molecules
function by forming a/an b
so that the
c
of reactions are greatly lowered.
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1
Please stick the barcode label here.
The diagram below represents stages in cell differentiation leading to the formation of part of
a secondary xylem vessel in a woody stem.
a
State two changes which occur from stage 1 to stage 3.
(2 marks)
b
What is the function of the tissue labelled 3 in the figure above?
(1 mark)
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3
The graph below shows the changes in the water potential of the plasma along a capillary.
a
Describe the changes in water potential from the arterial end to the venous end of the
capillary.
(2 marks)
b
Explain your answer in a.
(4 marks)
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4
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5
The diagram below shows the recycling of nutrients in an ecosystem.
nutrients in animals
litter
nutrients in plants
faeces and
dead animals
a
A nutrient that is essential for plant growth is recycled in the way shown in the diagram.
Name this nutrient.
(1 mark)
b
Describe two ways in which the nutrient could be lost from the ecosystem.
(2 marks)
c
State one way in which the nutrient could enter the cycle to replace the loss.
(1 mark)
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nutrients in soil
The diagram below shows part of the human digestive system.
a
Explain why the ingested food needs to be digested.
(2 marks)
b
Using the symbol ‘X’, mark two locations on the diagram that are guarded by sphincters.
(1 mark)
(Mark your answer on the diagram above.)
c
Describe the functional relationship between structures A and C.
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(2 marks)
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Answers written in the margins will not be marked.
6
d
State how the digestion processes occurring in structure B differ from those in
structure D.
(3 marks)
e
Apart from digestion, name another nutritional process that occurs in E.
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(1 mark)
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Answers written in the margins will not be marked.
Please stick the barcode label here.
Two similar woody plants were used in an investigation. The stem of one plant was ringed
(the outer part of a part of the stem was cut) while the other was not. One leaf of each plant
was supplied with carbon dioxide in which the carbon was the radioactive isotope, 14C, as
shown in Figure 1 (other leaves are not shown). The plants were kept in bright light for one
hour. The level of radioactivity was then measured at four positions on each plant, as shown
in Figure 2. The numbers indicate the relative abundance of radioactivity detected at the
corresponding positions.
A
Figure 1
a
B
Figure 2
Which plant, A or B, was ringed? Mark an ‘X’ on the position at which the stem was
ringed on the ringed plant in Figure 2.
(1 mark)
(Mark your answer on Figure 2.)
b
Explain how radioactive carbon from the supplied carbon dioxide reached the buds at
the end of the stem.
(2 marks)
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7
c
Suggest why the level of radioactivity in the stem below the bud was lower than in the
bud itself.
(2 marks)
d
Explain the results in the ringed plant.
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(3 marks)
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Answers written in the margins will not be marked.
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The diagram below shows a human foetus inside its mother’s uterus.
a
State the role of structure A during labour.
b
Name the structure from which fluid B is secreted. State the role of fluid B during labour.
(2 marks)
c
State two adaptive features of structure C to its function.
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(1 mark)
(2 marks)
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Answers written in the margins will not be marked.
8
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9
In the ABO blood group system, a single gene with three alleles controls the production of
the antigens that determine a person’s blood group. Table 1 shows the type of antigen each
allele is responsible for. Table 2 shows the different genotypes and their corresponding blood
groups.
Allele
Antigen produced
IA
Antigen A
IB
Antigen B
IO
No antigen produced
Table 2
Genotype
Blood group
IA IA or IA IO
A
IB IB or IB IO
B
IA IB
AB
IO IO
O
a
Explain why people with genotype IA IB are of blood group AB.
b
Explain how meiosis results in the production of two different types of gametes in
people of blood group AB.
(2 marks)
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(1 mark)
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Answers written in the margins will not be marked.
Table 1
A couple have four children whose blood groups are different. Deduce the blood groups
of the couple. Draw a genetic diagram to show how it is possible for their four children
to have different blood groups.
(3 marks)
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Answers written in the margins will not be marked.
c
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10
The diagram below shows a basic unit of DNA.
K
M
P
a
Name K, L, M and P.
b
i
(4 marks)
Part of a DNA molecule has the sequence of bases shown below. Write the
sequence of bases in the corresponding part of the mRNA molecule synthesized
upon the DNA.
(1 mark)
DNA molecule
A
T
C
G
mRNA molecule
ii
c
Name the process in which an mRNA molecule is synthesized from a DNA
template.
(1 mark)
The percentage of bases in one strand of a DNA double helix is as follows:
T = 40%
i
and
C = 22%
What is the percentage of bases A and G together in the same strand of DNA?
Show your calculations.
(1 mark)
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L
d
What is the percentage of bases A and G together in the complementary strand of
DNA? Show your calculations.
(1 mark)
The following section of mRNA codes for a polypeptide made of 10 amino acids. The
sequence of bases is shown below:
Code starts
Code ends
↓
↓
A-U-G-G-C-U-G-C-U-A-G-U-A-G-U-C-G-A-A-G-U-A-U-G-A-G-U-G-C-U
When the polypeptide was analysed, four types of amino acids and the number of each
of them were identified as shown in the table below:
Name of amino acid
Symbol
Number of the amino acid
Methionine
M
2
Alanine
L
3
Arginine
R
1
Serine
S
4
Work out the amino acid sequence in the polypeptide and write the correct sequence in
the boxes provided, using the symbols from the table.
(3 marks)
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Answers written in the margins will not be marked.
Answers written in the margins will not be marked.
ii
Please stick the barcode label here.
11
a
The diagram below shows the light-coloured and dark-coloured varieties of the
peppered moth, Biston betularia, in the rural area of a country.
tree bark
light-coloured
variety
Answers written in the margins will not be marked.
An investigation of the number of the moths was carried out in the rural area. It
involved marking, releasing and recapturing these moths. The table below shows the
results obtained.
Variety
Number marked
and released
Percentage
recaptured
Light colour
320
60
Dark colour
280
40
Explain the results in terms of natural selection
b
(3 marks)
Over the last 10 000 years the water level in Lake Turkana in Kenya has fluctuated
considerably. A volcanic island in the lake has a crater which was filled up with water
and fish when the water level was high. Later it became isolated as the water level fell.
A species of fish, Tilapia nilotica, is found in the main lake but a different species,
Tilapia vulcani, is found in the crater. The two species are very similar in appearance
which suggests a common ancestor. The diagram on the next page shows a map of Lake
Turkana and the volcanic island.
Answers written in the margins will not be marked.
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dark-coloured
variety
What can scientists do to identify that Tilapia nilotica and Tilapia vulcani are two
different species?
(1 mark)
ii
Suggest an explanation of how the species known as Tilapia vulcani might have
arisen.
(4 marks)
Answers written in the margins will not be marked.
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i
Please stick the barcode label here.
a
b
Most newborn babies develop natural immunity to measles because antibodies to
measles are present in their blood at birth. The concentration of these antibodies
decreases quickly after birth. When the babies reach 6 to 12 months old, the
concentration of the antibodies decreases to a level that the babies become susceptible
to measles.
i
State the term given to the type of natural immunity described above.
(1 mark)
ii
Suggest a possible source of antibodies to measles in the blood at birth. (1 mark)
Mandy is two years old. She has not been vaccinated against measles and became
infected with the disease. A study was carried out to measure the concentration of
antibodies to measles in her blood at regular intervals. The figure below shows the
results for the first eight weeks of this study.
8
7
6
5
4
3
2
1
0
0
1
2
3
4
5
6
7
8
time (week)
infection
i
Which type of cells is responsible for antibody production?
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(1 mark)
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Answers written in the margins will not be marked.
12
Explain why there is a delay between the time of infection and the first appearance
of antibodies in the blood.
(1 mark)
iii
Is Mandy likely to develop the symptoms of measles if she is exposed to the
pathogens again? Explain your answer.
(4 marks)
Answers written in the margins will not be marked.
Answers written in the margins will not be marked.
ii
c
Some children cannot develop immunity against measles if the measles vaccine is given
too early, e.g. before 6 months old. Suggest one reason for this.
(1 mark)
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Please stick the barcode label here.
Early scientists such as Carl Linnaeus put living organisms into two Kingdoms: the Plant
Kingdom and the Animal Kingdom. Seed plants, ferns, mosses, algae, fungi and even
bacteria were all classified as plants. Under the six-kingdom system of classification, algae,
fungi and bacteria are no longer plants. They fall into Kingdom Protista, Kingdom Fungi and
Kingdom Eubacteria respectively. With reference to the characteristics of algae, fungi and
bacteria, discuss why the six-kingdom system is a better classification system than the
two-kingdom system.
(10 marks)
Answers written in the margins will not be marked.
Answers written in the margins will not be marked.
13
– END OF PAPER –
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DSE
BIO
Mock Exam I
PAPER 2
New Senior Secondary
MASTERING BIOLOGY
(Second Edition)
BIOLOGY PAPER 2
HKDSE MOCK EXAM I
Time allowed: 1 hour
This paper must be answered in English
INSTRUCTIONS
1
There are FOUR sections, A, B, C and D in this Paper. Attempt ALL questions in any TWO sections.
2
Write your answers in the Answer Book. Start each question (not part of a question) on a new page.
3
Present your answers in paragraphs wherever appropriate.
4
Illustrate your answers with diagrams wherever appropriate.
5
The diagrams in this Paper are NOT necessarily drawn to scale.
Not to be taken away before the
end of the examination session
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SECTION A
Human Physiology: Regulation and Control
Answer ALL parts of the question. Put your answers in ONE of the answer books.
1
a
The diagram below represents a nephron and the associated blood vessels. Samples were
removed using a micropipette from three sites labelled A, B and C on the diagram.
The samples were then tested using Benedict’s reagent and Albustix paper. The results of
the tests are shown in the table below:
Site of
nephron
Result of
Benedict’s test
Result of
Albustix test
A
+++
+++
B
+++
+
C
–
–
Key
+++ represents a strong reaction
+ represents a very weak reaction
– represents no reaction
i
Explain the results of the Benedict’s test for the samples from sites A, B and C.
(3 marks)
ii
Explain the results of the Albustix test for the samples from sites A, B and C.
(3 marks)
iii
The concentrations of urea in 100 cm3 of the fluid at sites B and C are 0.03 g and
2.00 g respectively. Give one reason for such a difference.
(1 mark)
iv
Describe and explain the role played by structure D to keep the concentration of the
blood plasma of a man constant after he has drunk 0.5 L of distilled water.
(3 marks)
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1
b
The diagram below shows the spread of electrical impulses through the heart and the time
taken (in seconds) to reach the various parts.
i
‘Beating of the heart is under control by the heart itself and by the nervous system.’
Explain what this statement means.
(3 marks)
ii
Using the information in the diagram, suggest the time period during which atrial
systole takes place.
(2 marks)
iii
The atria have completed contraction by the time that electrical impulses from the
sinoatrial (SA) node are spread to the ventricles. What is the significance of such a
delay in the contraction of the ventricles?
(2 marks)
iv
What is the advantage of this path of transmission of electrical impulses to the
pumping of blood out of the heart?
(3 marks)
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SECTION B
Applied Ecology
Answer ALL parts of the question. Put your answers in ONE of the answer books.
2
a
The photograph below shows a gorilla, which is used to live in the tropical rainforests.
The gorilla has become an endangered species although it has no known enemies, except
humans. Gorillas are herbivorous, feeding on fruit, shoots, tree bark and leaves.
i
Suggest two reasons why the gorilla has become an endangered species.
(2 marks)
ii
Explain how captive breeding programmes in zoos may increase the reproductive
rate of endangered species such as the western lowland gorilla.
(2 marks)
iii
State two disadvantages of captive breeding programmes.
iv
Name an endangered species in Hong Kong. Describe how it is threatened by human
activities, and the measures the Hong Kong government has taken to protect it.
(4 marks)
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(2 marks)
2
b
The diagram below shows a map of a river system.
i
State two areas in the map where a relatively high concentration of ammonium
compounds may enter the river system. Explain your answer.
(2 marks)
ii
Cereals and beans are grown in area X. State two ways in which such farming
activities could cause an increase in the nitrate level of the lake.
(2 marks)
iii
Describe the effects of deforestation of the pine forest in area D on the organisms in
the river.
(3 marks)
iv
In late spring each year, the lake water turns green and a large number of fish die.
Give an explanation for this phenomenon.
(3 marks)
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SECTION C
Microorganisms and Humans
Answer ALL parts of the question. Put your answers in ONE of the answer books.
3
a
The diagram below shows the procedures of culturing microorganisms from a sample of
fresh soil taken from a riverbed.
i
State and explain how the water should be treated before it is used in the procedures
shown.
(2 marks)
ii
State three precautions that must be taken in procedure Q.
iii
The Petri dish was incubated under 35°C. Two days later, three microbial colonies
appeared on the nutrient agar. A sample of each colony was collected and observed
under the microscope. Below are the descriptions of the observation.
(3 marks)
Colony 1: Filamentous, colourless, with circular structure extended from
a stalk-like structure
Colony 2: Single-celled, round-shaped, cannot move
Colony 3: Pointed at two ends, green in colour, can move about freely
Suggest which group of microorganism each colony belongs to.
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(3 marks)
3
b
Read the article below and answer the questions.
Yoghurt is produced from milk. In the
production process of a brand of yoghurt, raw
milk is first pasteurized. The milk is then kept
at 40°C. Two species of bacteria, Lactobacillus
bulgaricus and Streptococcus thermophilus, are
added into the milk for carrying out
fermentation.
Fermentation of milk sugar (lactose) by Lactobacillus bulgaricus produces lactic
acid, while fermentation of milk proteins by Streptococcus thermophilus produces
acetaldehyde. This gives a specific taste of the yoghurt.
i
Describe how raw milk is pasteurized. Explain why pasteurizing milk at the
beginning of the production process is important.
(3 marks)
ii
Why is the pasteurized milk kept at 40°C?
iii
What are the roles of Lactobacillus bulgaricus and Streptococcus thermophilus
in the production of yoghurt?
(3 marks)
iv
At the end of the process, the activity of the bacteria decreases significantly.
Why does this happen?
(2 marks)
v
Sometimes, a small portion of the yoghurt produced is added into the pasteurized
milk. How can this facilitate the production of yoghurt?
(1 mark)
vi
On the package of the brand of yoghurt mentioned in the passage above, the
following statement is highlighted:
(2 marks)
‘Safe for lactose-intolerance’
Is such a claim valid? Explain briefly.
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(1 mark)
SECTION D
Biotechnology
Answer ALL parts of the question. Put your answers in ONE of the answer books.
4
a
Parentage test is one of the applications of DNA fingerprinting. The photograph below
shows the DNA fingerprints of a child, his mother and two men, F1 and F2. Both F1 and
F2 claim that they are the father of the child.
i
What does each band in the DNA fingerprints consist of?
ii
State one difference between band 3 and band 5 of the child’s DNA fingerprint.
(1 mark)
iii
Name the technique that separates the DNA fragments in DNA fingerprinting.
(1 mark)
iv
Which of the two men, F1 or F2, is the biological father of the child?
Explain your answer.
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(1 mark)
(2 marks)
4
b
One of the most important breakthroughs in modern biotechnology in the late 20th century
is genetic engineering.
i
What is genetic engineering?
(2 marks)
Gene selection begins when DNA is cut into shorter fragments by a restriction enzyme.
There are two types of restriction enzymes. The diagrams below show the way each
enzyme cuts the DNA strands.
Type 1 restriction enzyme
Type 2 restriction enzyme
ii
Which type of restriction enzyme, type 1 or 2, is used in cutting DNA during gene
selection? Explain your answer.
(3 marks)
In gene therapy, normal genes are introduced into cells containing defective genes. In an
attempt to treat cystic fibrosis, viruses are used to introduce normal genes into cells.
iii
Explain how introduction of the normal genes into the body helps treat the disease.
(2
marks)
iv
Give two reasons and one potential hazard of using a virus to introduce the genes
into the cells.
(3 marks)
v
The normal genes can be incorporated in either somatic cells, zygotes or gametes. At
present, gene therapy is limited to replacing genes in body cells.
vi
(1)
Suggest two advantages of performing gene therapy on a zygote or gamete rather
than on a somatic cell.
(2 marks)
(2)
Give one reason why gene therapy involving zygotes or gametes is not allowed
in many countries.
(1 mark)
Some people do not agree with the use of gene therapy to treat genetic diseases in
humans. Give two possible arguments raised by those people against gene therapy.
(2
marks)
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– END OF PAPER 2 –
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Biology
HKDSE Mock Exam I
Answers
Paper 1 Section A
Question no.
1
2
3
4
5
6
7
8
9
10
11
12
Answer
A
B
D
A
D
B
A
D
C
A
B
B
Question no.
13
14
15
16
17
18
19
20
21
22
23
24
Answer
A
C
D
A
A
A
D
C
A
C
D
D
Question no.
25
26
27
28
29
30
31
32
33
34
35
36
Answer
C
C
B
A
C
C
D
A
C
B
B
D
Paper 1 Section B
1
2
3
4
5
6
The tails of the two layers of molecules are water-repelling, so they point inwards to each other.
1m
The heads are water-loving, so they point outwards to the aqueous environment.
1m
a enzymes
1m
b enzyme-substrate complex
1m
c energy barrier
1m
a The nucleus disappears. /
The cell wall thickens. /
The cell contents and the end wall disappear. (any 2)
1m ´ 2
b For transporting water.
1m
a The water potential of the plasma gradually decreases
1m
and then increases again from the arterial end to the venous end of the capillaries.
1m
b In the arterial end, the pressure of the blood is higher than the pressure of the tissue fluid.
1m
Water moves from the plasma to the tissue fluid by osmosis and the water potential of the plasma
gradually decreases.
1m
In the venous end, the pressure of the blood is lower than the pressure of the tissue fluid.
1m
Water moves from the tissue fluid to the plasma by osmosis and the water potential of the plasma
gradually increases.
1m
a Nitrates
1m
b Harvesting of crops /
Leaching from the soil /
Denitrification (any 2)
1m ´ 2
c Nitrate formation through lightning / Nitrates added by applying fertilizers
1m
a They are broken down into small and soluble molecules,
1m
so that they can be absorbed.
1m
b Correct marking at the junction between the oesophagus and the stomach, and the junction between
the stomach the duodenum
1m
c The bile produced by structure C
1m
is temporarily stored in structure A.
1m
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7
8
9
d In structure B, the digestion processes occur under acidic conditions,
while in structure D, the digestion processes occur under alkaline conditions.
1m
In structure B, chemical digestion of proteins takes place,
while in structure D, chemical digestion of proteins, carbohydrates and lipids takes place.
1m
In structure B, mechanical digestion of food involves churning,
while in structure D, mechanical digestion of food involves the emulsification of lipids.
1m
e Absorption of digested food
1m
a Correct marking on plant B, at the place just below the leaf
1m
b Carbon dioxide was used to form glucose / sugar by photosynthesis.
1m
The labelled sugar was translocated upwards in the phloem.
1m
c Organic food was accumulated / stored in the bud.
1m
Organic food was incorporated into products of growth.
1m
d Ringing removed phloem.
1m
Sugars / Carbohydrates could not be translocated to the roots through the phloem,
1m
so there was no radioactivity in the root.
1m
a The muscles contract strongly and repeatedly to push the foetus out of the mother’s body.
1m
b Fluid B is secreted from cells in the amnion.
1m
Fluid B acts as a lubricant of the birth canal during labour.
1m
c It has numerous capillaries for the exchange of materials between the mother and the foetus. /
The villi provide a large surface area for the exchange of materials. /
The membrane separating the foetal and maternal blood is very thin. This provides a short distance
for the movement of substances during exchange. (any 2)
1m ´ 2
a Alleles IA and IB are co-dominant. /
Both alleles (IA and IB) are expressed so that both antigens are produced.
1m
b Since IA and IB are on different chromosomes of a homologus pair,
1m
A
B
when the chromosomes separate at anaphase I, there will only be one allele (I or I ) in each gamete.
1m
c Parents
Genotypes of parents
Blood group A (mother)
IA IO
Gametes
Genotypes of children
Phenotypes of children
(blood group)
IO
IA
IA IB
AB
IO IO
O
Blood group B (father)
IB IO
´
IB
IB IO
B
1m
IO
O
IA IO
A
2m
10 a K: phosphate; L: deoxyribose; M: nitrogenous base; P: nucleotide
1m ´ 4
b i UAGC
1m
ii Transcription
1m
c i 100 – (40 + 22) = 38%
1m
ii 40 + 22 = 62%
1m
d M L L S S R S M S L
3m
11 a Since the tree bark was light-coloured,
1m
the dark-coloured moths on tree barks were easily seen and eaten by predators / birds.
1m
The light-coloured moths reproduced more rapidly. Therefore, there were a larger number of
the light-coloured variety than the dark-coloured variety.
1m
b i
The two species do not interbreed or fail to produce fertile offspring when they are reared
together. / Perform DNA test / DNA fingerprinting.
1m
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ii
When the water flooded the crater, it contained ancestors of Tilapia nilotica from the lake.
1m
The fish population in the crater was isolated from that in the lake.
1m
Mutations took place separately in the isolated population, leading to new features differed
from the original population.
1m
As the two populations could not meet (due to physical barrier), they have become increasingly
different that they are unable to interbreed.
1m
12 a i
Passive immunity
1m
ii Antibodies in the mother’s blood enter the blood of the foetus through the placenta.
1m
b i Plasma cells
1m
ii Upon the first exposure to the measles antigens, time is required for the body to produce enough
antibodies and cells (plasma cells, killer T cells and memory cells) to act against the antigens. 1m
iii No.
1m
When the measles antigens enter the body again, the memory cells can respond quickly by
multiplying and differentiating into a larger number of plasma cells, killer T cells and memory
cells.
1m
The secondary response is fast, strong and lasts for a long period of time.
1m
It helps kill the pathogens before they multiply and cause diseases, so her body is able to resist
infection / immune to the disease.
1m
c The children’s immune system is not well developed yet. /
Antibodies from mother’s body interact with the measles vaccine, making the vaccine functionless. /
The children are suffering from malnutrition and do not have enough proteins in the body to produce
antibodies. /
The children have disease in lymphocyte development. (any 1)
1m
13 According to the six-kingdom system,
Ÿ Plants are multicellular and plant cells are highly differentiated into different structures, e.g. roots, stems
and leaves.
1m
Plant cells have a cell wall composed of cellulose. Some plant cells have chlorophyll / chloroplasts. 1m
Ÿ Some algae have chloroplasts, but they are single-celled. /
Some algae exist in groups without differentiation.
1m
Ÿ Fungi do not have chlorophyll / chloroplasts.
1m
Fungi have a cell wall which is not composed of cellulose. /
Fungi exist as a body of mycelium. They do not have a root system.
1m
Ÿ Bacteria are single-celled.
1m
Bacteria are prokaryotic (without a true nucleus) while plants are eukaryotic (with a true nucleus). 1m
Effective communication
3m
Paper 2
1
a i
Positive result for Benedict’s test indicates the presence of reducing sugar (glucose).
1m
Glucose from afferent arteriole (A) is filtered freely into the Bowman’s capsule (B).
1m
It is completely reabsorbed in the proximal convoluted tubule by diffusion and active transport. 1m
ii Positive result for Albustix test indicates the presence of proteins.
1m
Most proteins cannot be filtered into the Bowman’s capsule due to their large molecular size. 1m
Small proteins are able to enter the Bowman’s capsule but they are completely reabsorbed in
the proximal convoluted tubule.
1m
iii A greater proportion of water than urea has been reabsorbed from the kidney tubules.
1m
iv The hypothalamus / pituitary gland secretes less antidiuretic hormone (ADH).
1m
So the permeability of the collecting duct (D) to water decreases and a smaller proportion of
water is reabsorbed.
1m
Consequently, a larger volume of dilute urine is produced.
1m
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b i
2
3
Controlled by the heart: The sinoatrial (SA) node regularly generates electrical impulses which
spread to other parts of the heart to control its beating.
1m
Controlled by the nervous system: When the blood pH or blood pressure falls, the
cardio-acceleratory centre sends more nerve impulses along the sympathetic nerve
1m
to stimulate the SA node to increase the heart rate and stroke volume.
1m
ii 0 to 0.12 s / Initial tenth of a second
2m
iii This allows the ventricles to fill completely with blood
1m
before they contract.
1m
iv Initiation of electrical impulses from the SA node enables the atria to pump blood into the
ventricles.
1m
Spread of the electrical impulses from the bottom to the upper parts of the ventricles allows the
ventricles to contract upwards from the bottom.
1m
This forces blood more readily into the major arteries.
1m
a i
They are excessively killed because people think that they are dangerous to humans. /
Their habitats / Tropical rain forests are destroyed. /
They are threatened by diseases. (any 2)
1m ´ 2
ii The endangered species are kept in protected areas. Using in vitro fertilization (IVF), a higher
reproductive rate can be achieved.
1m
The newborn and the young animals have a higher survival rate since they are in the care of the
zoos.
1m
iii The gene pool is too small to produce offspring with more genetic variations. /
The captive-bred animals may have difficulty in adapting to the natural environment after being
released. /
Pathogens are more easily transferred among the captive-bred animals. (any 2)
1m ´ 2
iv Black-faced spoonbill
1m
The government has set up protected areas (e.g. Ramsar site) to protect its habitats from
disturbances by human activities.
1m
Possession and sale of the black-faced spoonbill or its body parts are prohibited by law.
1m
The government has set up the Hong Kong Wetland Park for educating the public about the
importance of wetland conservation. The ecological value of the black-faced spoonbill is
highlighted.
1m
(Accept other reasonable answers. Do NOT accept Chinese White Dolphin)
b i Area A: The cattle waste is converted to ammonium compounds by putrefying bacteria.
1m
Area E: The effluent produced from sewage treatment works is rich in inorganic nutrients such
as ammonium compounds.
1m
ii Chemical fertilizers applied to the cereal field may leach into the lake through the river.
1m
Decomposition of the dead remains of the bean plants may release nitrates which leach into the
lake through the river.
1m
iii Due to soil erosion, the run-off soil particles suspend in water and reduce light penetration.
1m
Aquatic plants and algae cannot get enough sunlight for photosynthesis and die.
1m
Since the aquatic plants and algae are food sources for aquatic animals, the animals have no
food and die.
1m
iv Concentrations of nitrates and phosphates in water increase to a high level.
1m
With suitable temperature and high light intensity, this results in an algal bloom.
1m
At night, the algae consume a large amount of dissolved oxygen for respiration, and a large
number of fish are suffocated to death.
1m
a i
The water should be boiled / distilled to kill all microorganisms present.
1m
This ensures that any microorganisms present in the nutrient agar come from the soil only.
1m
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ii
iii
b i
ii
iii
iv
v
vi
4
a i
ii
iii
iv
b i
ii
iii
iv
v
vi
The mouth of the culture bottle must be flamed after the cap is removed and before the cap is
replaced.
1m
The inoculating loop must be flamed and cooled beside the flame before and after use.
1m
The cover of the Petri dish is slightly opened for inoculation.
1m
Colony 1: Fungi
1m
Colony 2: Bacteria
1m
Colony 3: Protists
1m
Raw milk is heated to a temperature of 71°C for a short period of time (15 seconds).
1m
The milk is then cooled down rapidly.
1m
This aims to kill the microorganisms that are harmful to the human body.
1m
This provides the optimum temperature for the growth of the added bacteria.
1m
This provides the optimum temperature for the activities of enzymes involved in fermentation. 1m
Lactobacillus bulgaricus converts milk sugar into lactic acid which lowers the pH of the yoghurt.
This allows the proteins to coagulate / denature and gives the texture of the yoghurt.
1m
The lowered pH / increased acidity also prevents the growth of other unwanted microorganisms. 1m
Streptococcus thermophilus converts milk proteins into acetaldehyde which gives the specific
taste of the yoghurt.
1m
As more acid is produced, the pH of the culture medium becomes too low for the growth of the
bacteria / activity of bacterial enzymes.
1m
Waste products accumulate in the culture medium, making it unfavourable for the growth of the
bacteria.
1m
Living and active bacteria are present in the yoghurt. They can start the conversion of milk sugar
and milk proteins more quickly.
1m
Yes, it is valid.
The lactose content in the milk is drastically decreased as lactose is fermented by bacteria /
Lactobacillus bulgaricus.
1m
DNA fragments which are short tandem repeats / variable number tandem repeats.
1m
Band 3 has a longer base sequence than band 5.
1m
Gel electrophoresis
1m
F1
1m
DNA of F1 shares half of the DNA bands of the child (i.e. bands 2, 4, 7, 9 and 10)
1m
Genetic engineering is the changing of the genetic make-up of an organism
1m
by direct manipulation of its genetic material.
1m
Type 2
1m
The staggered cuts are sticky ends
1m
which can join a complementary end of a different DNA fragment.
1m
The defective gene produces a wrong protein that cannot perform the normal function.
1m
Expression of the normal gene incorporated in the genome produces the protein that performs
the normal function.
1m
Reasons:
Viruses infect / enter cells readily.
1m
Viruses infect specific cells only. / Viruses are specific in action.
1m
Potential hazard:
Viruses may cause disease / harm to the human body.
1m
(1) Performing gene therapy on a zygote may correct a disease before it develops in the
individuals.
1m
The genetic correction in germ line therapy is inheritable.
1m
(2) Future generations are unable to give consent. /
It may result in designer babies / eugenics / can cause new mutations.
1m
The cost is high when compared with conventional treatments.
1m
The genes introduced may have unknown / adverse effects on other genes.
1m
New Senior Secondary Mastering Biology (Second Edition)
Mock Exam I Biology Answers
ã Oxford University Press 2014
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