PLACE
LABEL
HERE
Tasmanian Secondary Assessment Board
Tasmanian Certificate of Education
External Assessment
1997
BY826 BIOLOGY
SECTION A
Time: 35 minutes
On the basis of your performance in this examination, the examiners will provide a rating of A, B, C
or D on the following criterion taken from the syllabus statement:
Criterion 3
Pages:
Questions:
©
Demonstrate understanding and knowledge of biological
principles and how they apply to the molecular and cellular levels
of biological organisation.
8
3
Copyright for part(s) of this examination may be held by individuals and/or organisations other than the Tasmanian
Secondary Assessment Board.
BY826 Biology
GENERAL INSTRUCTIONS
Answer ALL questions. Answers must be written in the spaces provided on the exam paper.
Information written outside the spaces will not necessarily be taken into consideration.
Candidates are reminded that spelling and expression which make it difficult for the examiner to
understand what candidates mean, will result in loss of marks.
_______________________________________________________________________________
Page 2
BY826 Biology
SECTION A
This section assesses Criterion 3
Suggested Time : 35 minutes
Question 1
(a)
Refer to the diagram below which shows a cell that was drawn from a photomicrograph.
A
D
B
E
C
F
(i)
Name the organelle labelled B.
(1 mark)
.........................................................................................................
(ii)
State the function of the structure labelled in D.
(1 mark)
.........................................................................................................
.........................................................................................................
(iii) Write the letter that identifies an organelle in which a large amount of ATP is produced.
(1 mark)
.........................................................................................................
(iv)
State one piece of evidence that indicates that the photomicrograph was produced using an
electron microscope.
(1 mark)
.........................................................................................................
(b)
The width of the cell is 90 µm. Estimate the diameter of the nucleus of the cell.
(1 mark)
.................................................................................................................
(c)
State one piece of evidence that indicates that this is an animal cell.
(1 mark)
.................................................................................................................
Question 1 continues over the page.
Page 3
BY826 Biology
Question 1 (continued)
(d)
The diagram below illustrates the nucleus of a cell undergoing division.
1
(i)
3
2
4
Using the numbers from the diagram list the correct sequence for cell division. (2 marks)
.........................................................................................................
(ii)
Which type of cell division does this sequence represent?
(1 mark)
.........................................................................................................
(e)
The diagram below shows the amount of DNA per cell in a dividing cell.
B
X
Amount of
DNA/Cell
C
A
D
Time
(i)
What is happening to the DNA at X and what name is given to this process?
(1 mark)
.........................................................................................................
.........................................................................................................
(ii)
Which stage(s) are:
(1 mark)
diploid (2n)?
....................................................................................
haploid (1n)?
....................................................................................
(iii) What event could again change the amount of DNA in the cells that are produced at D?
(1 mark)
............................................................................................................................................
............................................................................................................................................
Total Question 1:
Page 4
/12
BY826 Biology
Question 2
(a)
Plants are sometimes referred to as ‘energy converters’. Briefly trace the energy flow within a
green plant cell, highlighting the key processes involved.
(6 marks)
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
(b)
The enzyme amylase catalyses the breakdown of starch into maltose as follows.
amylase
starch 
→ maltose + water
An experiment (Experiment 1) was carried out to investigate how varying the concentration of
starch affected the rate of the reaction. The concentration of enzyme, pH and temperature were
kept constant throughout the experiment. The results are show in the figure below.
Rate of
Reaction
(arbitrary
units)
X
Y
Experiment 1
Starch Concentration
(arbitrary units)
(i)
Explain why the reaction rate increases until starch concentration reaches point X.
(1 mark)
............................................................................................................................................
............................................................................................................................................
(ii)
Explain why the reaction rate is constant between points X and Y.
(1 mark)
............................................................................................................................................
............................................................................................................................................
Question 2 continues over the page.
Page 5
BY826 Biology
Question 2 (continued)
(c)
Another experiment (Experiment 2) was conducted with an increased amount of enzyme and the
results plotted on the same graph as those of Experiment 1. The graph is as follows.
.
Rate of
Reaction
(arbitrary
units)
Graph A
.
Experiment 1
Graph B
Starch Concentration
(arbitrary units)
Explain which graph, Graph A or Graph B, represents the results of Experiment 2.
(2 marks)
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
Total Question 2:
Page 6
/10
BY826 Biology
Question 3
(a)
An amoeba is a unicellular organism that lives in aquatic environments. The diagram below
shows the same amoeba in three different aquatic environments.
X
Y
Z
(i)
What can you conclude about the concentration of environment Z compared to the
concentration of the amoeba placed in it?
(1 mark)
............................................................................................................................................
............................................................................................................................................
(ii)
Name and describe the main process that is occurring in the amoeba in environment Y.
(3 marks)
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
(iii) Why is it necessary for all freshwater animals to osmoregulate but not freshwater plants?
(2 marks)
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
Question 3 continues over the page.
Page 7
BY826 Biology
Question 3 (continued)
(b)
Selectively permeable membranes are crucial to the viability of cells.
(i)
To what extent is the cell (plasma) membrane responsible for the cell’s homeostatic
balance. Briefly discuss its role in the regulation of the cell’s internal environment.
(3 marks)
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
(ii)
It is generally accepted that the development of eukaryotic cells was one of the most
important evolutionary advances.
Using examples, outline two ways in which internal membranes have been adapted to
serve a range of useful functions in the cell.
(2 marks)
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
Total Question 3:
Page 8
/11
PLACE
LABEL
HERE
Tasmanian Secondary Assessment Board
Tasmanian Certificate of Education
External Assessment
1997
BY826 BIOLOGY
SECTION B
Time: 35 minutes
On the basis of your performance in this examination, the examiners will provide a rating of A, B, C
or D on the following criterion taken from the syllabus statement:
Criterion 4
Pages:
Questions:
10
3
Display understanding and knowledge of biological principles and
how they apply to the organism.
BY826 Biology
GENERAL INSTRUCTIONS
Answer ALL questions. Answers must be written in the spaces provided on the exam paper.
Information written outside the spaces will not necessarily be taken into consideration.
Candidates are reminded that spelling and expression which make it difficult for the examiner to
understand what candidates mean, will result in loss of marks.
_______________________________________________________________________________
_
Page 2
BY826 Biology
SECTION B
This section assesses Criterion 4
Suggested Time : 35 minutes
Question 4
(a)
The diagram below represents the gas exchange between an organism and its environment.
Blood flow
Gas exchange
Lungs or gills
X
Blood transports gases
Gas exchange
Y
Respiring cell
Blood flow
(i)
Name two gases exchanged at point X.
(1 mark)
.........................................................................................................
.........................................................................................................
(ii)
Name the process by which gases are exchanged at points X and Y.
(1 mark)
.........................................................................................................
(iii) List two structural characteristics that make lungs and gills efficient surfaces for gas
exchange.
(2 marks)
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
(iv)
Explain why a constant flow of blood is needed to maintain the exchange of gases at point
Y.
(2 marks)
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
Question 4 continues over the page.
Page 3
BY826 Biology
Question 4 (continued)
(b)
Both tall plants and animals face a challenge in moving fluids upwards through their circulatory
systems against gravity.
Briefly outline two ways in which this upward movement is assisted in a plant or animal you
have studied.
(3 marks)
......................................................................................................................................................
................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
(c)
The table below shows the breathing rate of a resting small mammal in an experimental
chamber. The number of breaths taken per minute (breaths min −1 ) is shown in the right
column. In different trials, the breathing rate was measured while gas with different mixtures of
CO2 and O2 was flowing through the chamber. Normal atmosphere contains 0.035% CO2 and
approximately 20% O2 .
Gas in
Gas out
Chamber with controlled gas flow
CO2
O2
N2
Gas bottles supplying oxygen,
carbon dioxide and nitrogen
% of CO2 in Gas
% of O 2 in Gas
Breaths min −1
Mixture 1
0.035
20
68
Mixture 2
0.05
20
69
Mixture 3
0.7
20
134
Mixture 4
0.035
15
72
Mixture 5
0.035
12
73
Question 4 continues opposite.
Page 4
BY826 Biology
Question 4 (continued)
Basing your answer around the information in the table describe how the process of breathing is
controlled.
(3 marks)
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
Total Question 4:
Page 5
/12
BY826 Biology
Question 5
(a)
Many examples of homeostatic feedback systems occur in the endocrine system of a
multicellular organism. The diagram below shows a schematic diagram of a feedback system.
Endocrine
organ
Message
Effector
Response
Feedback
(i)
Describe a specific example of such a system. State the anatomical structures/chemicals/
actions that correspond to Endocrine organ, Message, Effector and Response in the
diagram.
(4 marks)
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
(ii)
In your example for part (i) above, what is the effect of the response on the endocrine
organ? Is this effect positive or negative?
(2 marks)
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
Question 5 continues opposite.
Page 6
BY826 Biology
Question 5 (continued)
(b)
What are three important differences in nutritional requirements between a normal person and a
hospital patient fed through an intravenous drip?
(3 marks)
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
Total Question 5:
Page 7
/9
BY826 Biology
Question 6
(a)
The diagram below shows a specimen of the freshwater invertebrate, Hydra, which is able to
reproduce both sexually and asexually.
Q
P
(i)
Which of the pairs of labelled parts, P or Q, would be involved with sexual reproduction?
(1 mark)
.........................................................................................................
(ii)
What type of cell division would be occurring when Hydra reproduces asexually and
what is the significance of this type of cell division in relation to asexual reproduction?
(2 marks)
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
(iii) Hydra possesses both male and female sex organs.
disadvantage of this.
State one advantage and one
(2 marks)
Advantage: ...........................................................................................
.........................................................................................................
Disadvantage: ........................................................................................
.........................................................................................................
Question 6 continues opposite.
Page 8
BY826 Biology
Question 6 (continued)
(b)
This question is based on the following pedigree in which guinea pigs with black coats are
shown in black and white-coated guinea pigs are represented by white. Circles represent females
and squares represent males.
MALE
FEMALE
B
A
C
E
(i)
F
G
According to this pedigree, black coat colour in guinea pigs appears to be inherited as:
1.
2.
3.
4.
a dominant trait.
a recessive trait.
an intermediate trait.
a sex-linked recessive trait.
Correct number is:
(ii)
D
....................
(1 mark)
What would be the expected ratio of genotypes from a cross between guinea pigs
F and G? .............................................................................................
..........................................................................................................
B and D? .............................................................................................
..........................................................................................................
(2 marks)
(iii) What is the probability of the next offspring from the mating of guinea pigs B and A
being black coated?
(1 mark)
.........................................................................................................
Question 6 continues over the page.
Page 9
BY826 Biology
Question 6 (continued)
(c)
The body cells of a female platypus contain 54 chromosomes (two of which are sex
chromosomes), while the body cells of a male platypus contain 53 chromosomes (only one of
which is a sex chromosome).
With the use of a diagram or grid explain sex determination in the platypus species.
(3 marks)
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
Total Question 6:
Page 10
/12
PLACE
LABEL
HERE
Tasmanian Secondary Assessment Board
Tasmanian Certificate of Education
External Assessment
1997
BY826 BIOLOGY
SECTION C
Time: 35 minutes
On the basis of your performance in this examination, the examiners will provide a rating of A, B, C
or D on the following criterion taken from the syllabus statement:
Criterion 5
Pages:
Questions:
8
3
Demonstrate understanding and knowledge of biological
principles and how they apply to the interrelationships between
organism and environments.
BY826 Biology
GENERAL INSTRUCTIONS
Answer ALL questions. Answers must be written in the spaces provided on the exam paper.
Information written outside the spaces will not necessarily be taken into consideration.
Candidates are reminded that spelling and expression which make it difficult for the examiner to
understand what candidates mean, will result in loss of marks.
_______________________________________________________________________________
Page 2
BY826 Biology
SECTION C
This section assesses Criterion 5
Suggested Time : 35 minutes
Question 7
(a)
The first section of this question is based on the diagram below.
tapeworms
K
birds
lizards
frogs
earthworms
beetles
grasses &
shrubs
(i)
Name an organism which could well occupy position K in the food web above. (1 mark)
.........................................................................................................
(ii)
Indicate two different feeding relationships within the food web above by writing the
name for each above an appropriate arrow.
(1 mark)
(iii) Which vital group is not shown on the diagram?
(1 mark)
.........................................................................................................
(iv)
If the population of earthworms sharply declined, state with a brief explanation, the
expected effects on the populations of:
Birds
...............................................................................................
..........................................................................................................
Frogs
...............................................................................................
..........................................................................................................
(3 marks)
(v)
Name a species that has been introduced into Australia and describe two likely effects that
such an introduced species could have on the food web above.
(3 marks)
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
Question 7 continues over the page.
Page 3
BY826 Biology
Question 7 (continued)
(b)
The classification of four types of cats is represented by the following diagram.
T
U
V
W
X
Y
Z
(i)
At which level are the organisms most similar?
(1 mark)
.........................................................................................................
(ii)
Name the genus of the lion.
(1 mark)
.........................................................................................................
(iii) List two advantages of classification schemes.
(1 mark)
.........................................................................................................
.........................................................................................................
Total Question 7:
Page 4
/12
BY826 Biology
Question 8
(a)
DDT is a pesticide that was in widespread use for insect control during the 1950s and the
1960s. It has now been phased out in Australia and replaced by other chemicals. Recently a
group of scientists studied the concentrations of DDT in the environment and in the tissues of
living organisms. The following table gives the data for a marine ecosystem.
Sample
Concentration of DDT
(parts per million)
sea water
0.02
plankton
0.13
small fish
1.29
seagull
(i)
69.00
Draw a pyramid of biomass for this ecosystem and explain the shape of the diagram.
(4 marks)
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
(ii)
Explain the difference in the concentration of DDT in plankton and small fish. (2 marks)
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
Question 8 continues over the page.
Page 5
BY826 Biology
Question 8 (continued)
(iii) Even if DDT had not been banned because of its effect on the environment, it would still
have a limited period of time as an effective insecticide. Why?
(1 mark)
.........................................................................................................
.........................................................................................................
(b)
The element nitrogen is more abundant in the atmosphere than carbon. Explain why carbon is
more readily available to plants than nitrogen.
(3 marks)
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
Total Question 8:
Page 6
/10
BY826 Biology
Question 9
(a)
Common brushtail possums inhabit forests and woodlands along the entire east coast of
Australia. Possums from the rainforests of north Queensland have copper-coloured fur, while
those from Tasmania are dark grey or black. In New South Wales and Victoria fur colour is
typically a light brownish-grey.
(i)
Explain how such variations in fur colour may have arisen in these populations of
brushtail possums?
(4 marks)
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
(ii)
The three colour variants are assumed to belong to the same species. What evidence is
needed to prove that this assumption is correct?
(1 mark)
.........................................................................................................
.........................................................................................................
(iii) Given sufficient time, the Tasmanian possum could develop into a separate species.
Describe the role of isolation in this process.
(2 marks)
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
Question 9 continues over the page.
Page 7
BY826 Biology
Question 9 (continued)
(b)
There are many examples of animals and plants for which population numbers have fallen to
low levels and extinction is a strong possibility. For some vertebrate animals ‘captive breeding
programs’ have been started with the intention of reproducing animals which can later be
released into the wild. However, the success of these programs depends on more than just
breeding large numbers. There are important aspects of the genetic diversity of populations
which the breeders must understand.
Considering such issues of population genetics, how might breeders use the information
provided by geneticists to increase the chances of successfully reintroducing animals to the
wild?
(4 marks)
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
Total Question 9:
Page 8
/11
PLACE
LABEL
HERE
Tasmanian Secondary Assessment Board
Tasmanian Certificate of Education
External Assessment
1997
BY826 BIOLOGY
SECTION D
Time: 35 minutes
On the basis of your performance in this examination, the examiners will provide a rating of A, B, C
or D on the following criteria taken from the syllabus statement:
Criterion 8
Pages:
Questions:
5
3
Develop feasible hypotheses and design controlled experiments to
test hypotheses.
BY826 Biology
GENERAL INSTRUCTIONS
Answer ALL questions. Answers must be written in the spaces provided on the exam paper.
Information written outside the spaces will not necessarily be taken into consideration.
Candidates are reminded that spelling and expression which make it difficult for the examiner to
understand what candidates mean, will result in loss of marks.
_______________________________________________________________________________
_
SECTION D
This section assesses Criterion 8
Suggested time : 35 minutes
Question 10
A marine biologist wished to investigate factors which might affect the life present in intertidal rock
pools on a rocky shore. She collected the following data over a single 24 hour period in January just
before the tide returned to cover the pools.
Pool
Maximum
Depth (m)
Surface Area
( m 2)
Day Temp.
(˚C)
Night Temp.
(˚C)
1
0.09
2.13
24.8
13.1
11.7
2
0.14
2.07
23.5
13.4
10.1
3
0.20
1.90
20.8
13.6
7.2
4
0.26
1.99
21.3
13.8
7.5
5
0.57
1.96
18.6
14.0
4.4
Open Sea
–
–
15.6
13.9
1.7
(a)
Name three variables that were controlled in this experiment.
Difference in
Temp. (˚C)
(3 marks)
.................................................................................................................
.................................................................................................................
.................................................................................................................
(b)
Explain why sea water was also included in the tests.
(2 marks)
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
Question 10 continues opposite.
Page 2
BY826 Biology
Question 10 (continued)
(c)
For the experiment described, what was the
(i)
independent variable?
(1 mark)
.........................................................................................................
.........................................................................................................
(ii)
dependent variable?
(1 mark)
.........................................................................................................
.........................................................................................................
(d)
What hypothesis was being tested?
(3 marks)
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
(e)
After the experiment described, the marine biologist performed many similar experiments. Why
is it necessary to repeat an experiment a number of times?
(1 mark)
.................................................................................................................
.................................................................................................................
.................................................................................................................
Total Question 10:
Page 3
/11
BY826 Biology
Question 11
The coffee plantations in Northern Queensland suffered a dramatic crop failure last year. Most of the
coffee berries failed to mature properly, the outer casing went black with very little bean development
inside.
Growers in the area put the blame on the State Department of Agriculture who had sprayed
extensively in the district in an attempt to control the Papaya Fruit Fly, claiming it was the spray that
ruined the crop.
(a)
Outline a suitable testing program to find out if the spray was the likely cause of the problem.
(8 marks)
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
(b)
Suggest another possible hypothesis to account for the crop failure.
(3 marks)
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
Total Question 11:
Page 4
/11
BY826 Biology
Question 12
(a)
The saliva of some cigarette smokers is less effective in digesting starch than is the saliva of
some non-smokers.
Outline some of the difficulties faced in testing the hypothesis that cigarette smoke inactivates
salivary amylase, and how they could be overcome.
(6 marks)
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
(b)
It has been claimed on television lately that pills containing extracts from celery seeds can
reduce the aches and pains in joints that are caused by arthritis.
What ethical issues must be considered and how could you take them into account when
designing an experiment to test this claim?
(4 marks)
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
Total Question 12:
Page 5
/10
PLACE
LABEL
HERE
Tasmanian Secondary Assessment Board
Tasmanian Certificate of Education
External Assessment
1997
BY826 BIOLOGY
SECTION E
Time: 35 minutes
On the basis of your performance in this examination, the examiners will provide a rating of A, B, C or
D on the following criterion taken from the syllabus statement:
Criterion 9
Pages:
Questions:
7
3
Analyse, interpret and evaluate information and data gained (from
individual investigations and the investigations of others) and to
evaluate the methods used and conclusions drawn from these
investigations.
BY826 Biology
GENERAL INSTRUCTIONS
Answer ALL questions. Answers must be written in the spaces provided on the exam paper.
Information written outside the spaces will not necessarily be taken into consideration.
Candidates are reminded that spelling and expression which make it difficult for the examiner to
understand what candidates mean, will result in loss of marks.
_______________________________________________________________________________
SECTION E
This section assesses Criterion 9
Suggested Time : 35 minutes
Question 13
The English biochemist, Hopkins, left two groups of eight young male rats on a diet consisting of
pure protein, starch, sucrose, inorganic salts and water. Group A was given, in addition, a small daily
ration of milk representing about 4% of the total food eaten. Group B was given exactly the same diet
except that they received no milk. After 18 days the milk was switched from Group A and given to
Group B.
Average Mass of Animals/g
80
Group B
milk
stopped
70
Group A
milk
60
50
no milk
milk added
40
0
10
20
30
40
50
Days of Experiment
(a)
What was the increase in mass of Group B rats in the time from day 18 when their diet included
milk?
(1 mark)
.................................................................................................................
(b)
Why was it important to carry out this experiment on groups of rats rather than on two
individual rats?
(2 marks)
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
Question 13 continues opposite.
Page 2
BY826 Biology
Question 13 (continued)
(c)
What was the effect of milk and the absence of milk on the growth of the rats in Group A and
Group B as revealed by the graph?
(4 marks)
Group A: ...................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
Group B:
...................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
(d)
Consider the design of this experiment and discuss what the strengths and weakness are.
(4 marks)
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
.................................................................................................................
Total Question 13:
Page 3
/11
BY826 Biology
Question 14
A man was resting in a temperature controlled chamber which was kept at a constant temperature of
45˚C. His body temperature, rate of sweating and body heat loss were measured, and the results
plotted on graphs (see below). At the times shown he ate a quantity of crushed ice.
PERIOD B
ice eaten
PERIOD A
ice eaten
Temperature ˚C
37.8
internal body temperature
37.6
37.4
37.2
37.0
skin temperature
36.8
36.6
Rate of
Sweating
60
50
40
30
Heat Loss
from Man's Body
(joules per second)
20
120
80
40
0
–40
0
5
10
15
20
25
30
35
40
45
50
55
60
65
Time (minutes)
(a)
What happened to the following during the 25 minutes after the eating of ice?
The internal body temperature: ..........................................................................
.................................................................................................................
The skin temperature:
.............................................................................
.................................................................................................................
The rate of heat loss from the body: ....................................................................
.................................................................................................................
(3 marks)
Question 14 continues opposite.
Page 4
BY826 Biology
Question 14 (continued)
(b)
During the first 10 minutes after eating the ice, the skin temperature rose sharply. Why was
this?
(3 marks)
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.................................................................................................................
.................................................................................................................
(c)
How is the change in internal body temperature during Period B related to the rate of sweating?
(1 mark)
.................................................................................................................
(d)
Explain what this experiment tells you about the location of the temperature receptor. (3 marks)
.................................................................................................................
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Total Question 14:
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BY826 Biology
Question 15
(a)
Samples of water were taken from a river at a factory outflow and at a number of points
downstream. A clean freshwater stream entered the river some distance below the factory
outflow.
The table below shows the degree of pollution, determined by the oxygen content of the water, at
each sample point.
Distance from
Outflow/m
Oxygen Content/
Arbitrary Units
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
0.12
0.13
0.11
0.14
0.20
0.24
0.28
0.34
0.40
0.62
1.02
1.16
1.18
There is an inverse relationship between the reading on the scale of oxygen content and the level
of pollution. A reading of 1.2 on the scale for the oxygen content indicates zero pollution and a
reading of 0.0 indicates 100% pollution.
(i)
Use the table to suggest the distance from the outflow at which the fresh water entered the
river.
(1 mark)
..........................................................................................................
Explain the reasons for your choice.
(2 marks)
..........................................................................................................
..........................................................................................................
..........................................................................................................
..........................................................................................................
(ii)
How well do these readings prove that the factory is responsible for the river pollution?
What else could be done to strengthen the scientific evidence?
(4 marks)
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.........................................................................................................
.........................................................................................................
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Question 15 continues opposite.
Page 6
BY826 Biology
Question 15 (continued)
(b)
The graph below shows the relative metabolic rate for animals of different body weight.
Relative Metabolic
Rate
(Oxygen consumed
per kg per h)
e
mous
rat
0.01
0.1
1
cat
10
n
rse
ma
ho
100
1000
Body Weight (kg)
(i)
Describe the relationship shown in the graph.
(2 marks)
.........................................................................................................
.........................................................................................................
.........................................................................................................
.........................................................................................................
(ii)
What could be interpreted about the consumption of food per kg body weight and the size
of the animals?
(1 mark)
.........................................................................................................
.........................................................................................................
(iii) How does this information help to explain why there are few mammals much smaller than
a mouse?
(2 marks)
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Total Question 15:
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