GENERAL CERTIFICATE OF EDUCATION
TYSTYSGRIF ADDYSG GYFFREDINOL
2009 - 2010
BIOLOGY
SPECIMEN QUESTION PAPERS
SPECIMEN MARKING SCHEMES
GCE BIOLOGY Specimen Assessment Materials 3
Contents
Page
Question Papers
Unit 1
Biology/Human Biology
5
Unit 2
Biology
21
Unit 4
Biology
35
Unit 5
Biology/Human Biology
53
Unit 1
Biology/Human Biology
71
Unit 2
Biology
79
Unit 4
Biology
85
Unit 5
Biology/Human Biology
93
Mark Schemes
GCE BIOLOGY Specimen Assessment Materials 5
CYD-BWYLLGOR ADDYSG CYMRU
Tystysgrif Addysg Gyffredinol
Uwch Gyfrannol/Uwch
WELSH JOINT EDUCATION COMMITTEE
General Certificate of Education
Advanced Subsidiary/Advanced
BIOLOGY/HUMAN BIOLOGY
UNIT 1
SPECIMEN PAPER
(1 hour 30 minutes)
INSTRUCTIONS TO CANDIDATES
Write your name, centre number and candidate number in the spaces at the top of this page.
Answer all questions.
Write your answers in the spaces provided in this booklet.
INFORMATION FOR CANDIDATES
The number of marks is given in brackets at the end of each question or part-question.
You are reminded that assessment will take into account the quality of written communication
used in your answers.
No certificate will be awarded to a candidate detected in any unfair practice during the
examination.
GCE BIOLOGY Specimen Assessment Materials 6
1.
Complete the table below by placing ticks in the appropriate column(s). Each row may have
one or more ticks.
Monosaccharide
Disaccharide
Structural
Polysaccharide
Storage
Polysaccharide
Glucose is an example of
Cellulose is an example of
Amylose is an example of
Maltose is an example of
Insoluble
Deoxyribose is an example of
(Total 6 marks)
GCE BIOLOGY Specimen Assessment Materials 7
2.
The diagram below shows a section of DNA molecule.
(a)
Name the parts labelled A and B.
[1]
A ............................................
B ............................................
(b)
What type of bonding is shown at E?
[1]
..............................................................................................................................
(c)
(i)
What type of nitrogenous base is guanine?
[1]
..............................................................................................................................
(ii)
Name the bases C and D.
[2]
C ............................................
D ............................................
(d)
On the diagram above, draw a ring around a single nucleotide unit.
[1]
GCE BIOLOGY Specimen Assessment Materials 8
(e)
A large sample of DNA was analysed and it was found that guanine made up 28% of
the number of base molecules present. Calculate the number of thymine base
molecules present as a percentage.
You must show your working.
[3]
..............................................................................................................................
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(Total 9 marks)
GCE BIOLOGY Specimen Assessment Materials 9
3.
Beetroot cells contain a red pigment.
Cut cubes of beetroot were washed to remove the red pigment from damaged surface cells.
The cubes were placed in test tubes containing 10cm3 water, in waterbaths at a range of
temperatures.
The tubes were left at each temperature for 10 minutes.
The beetroot was removed from the tubes and the colour of the solution in the tube measured
on a colorimeter.
The darker the red colour of the solution, the greater the colorimeter reading.
The following results were obtained.
Temperature (ºC)
Colorimeter
Reading
(Arbitrary
units)
(i)
10
20
30
40
50
60
70
0
1
4
7
80
90
100
Describe the pattern of results from the above table.
[2]
..............................................................................................................................
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(ii)
Explain the results as fully as you can. Refer to cell membrane structure in your
answer.
[3]
..............................................................................................................................
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(iii)
Explain the difference in the results if you were investigating the effect of ethanol on
the permeability of the membrane.
[2]
..............................................................................................................................
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(Total 7 marks)
GCE BIOLOGY Specimen Assessment Materials 10
4.
In an experiment the enzyme catalase, obtained from liver tissue, was used to break down
hydrogen peroxide releasing oxygen. The experiment was carried out at selected pH values
and the volume of oxygen given off was measured at intervals. The results obtained were
plotted as shown below.
(a)
Which one of the four pH values would be nearest to the optimum for catalase?
[1]
..........................................
(b)
Select the letter which indicates:
(i)
The fastest rate of reaction.
[2]
..........................................
Give a reason for your choice. ................................................................
..................................................................................................................
(ii)
The least concentration of hydrogen peroxide.
[2]
..................................................................................................................
Give a reason for your choice ...............................................................
..................................................................................................................
(c)
Explain fully the results obtained at pH 4.4.
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[3]
GCE BIOLOGY Specimen Assessment Materials 11
(d)
A control was set up at optimum pH conditions using boiled and cooled liver.
Suggest an explanation for the shape of the control curve shown on the above graph.
[1]
..............................................................................................................................
..............................................................................................................................
(e)
Outline how the experiment could be modified in order to investigate the effect of the
concentration of catalase on the rate of the reaction.
[2]
..............................................................................................................................
..............................................................................................................................
..............................................................................................................................
..............................................................................................................................
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(Total 11 marks)
GCE BIOLOGY Specimen Assessment Materials 12
5.
Milk can be made lactose-free by passing it down a column of the immobilised enzyme
lactase.
An experiment was carried out to determine the optimum size of alginate beads to use in this
process.
Three bead sizes were prepared and placed in columns. The same volume of milk was run
into each column at the same rate of flow.
The percentage product for each experiment was calculated.
The entire experiment was repeated a number of times.
Bead diameter (mm)
Mean percentage of product
(a)
(i)
2
4
6
98
84
70
Suggest the bead size which should be used in the process. Give a reason for
your answer.
[1]
..................................................................................................................
..................................................................................................................
(ii)
Give two reasons for the different results from the three bead sizes.
[2]
..................................................................................................................
..................................................................................................................
..................................................................................................................
(iii)
What would you expect to happen to the results if the flow rate was
decreased? Explain your answer.
[2]
..................................................................................................................
..................................................................................................................
..................................................................................................................
(iv)
Which other factor should be kept constant during the experiment?
[1]
..................................................................................................................
(b)
Give two advantages of using immobilised enzymes in industrial processes.
[2]
..............................................................................................................................
..............................................................................................................................
..............................................................................................................................
(Total 8 marks)
GCE BIOLOGY Specimen Assessment Materials 13
6.
The diagram represents the nucleus of an animal cell (2n = 6) at early prophase of
mitosis.
(a)
In the space below draw an annotated diagram to indicate what happens to this cell at
anaphase of mitosis.
[4]
GCE BIOLOGY Specimen Assessment Materials 14
(b)
What events must occur during interphase before mitosis can take place?
[5]
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(Total 9 marks)
GCE BIOLOGY Specimen Assessment Materials 15
7.
When a potato tuber is cut open, the surfaces exposed to the air gradually turn brown due to
the production of dark brown coloured pigments from phenolic compounds (e.g. catechol).
The enzyme, polyphenol oxidase, catalyses this process.
The graph below shows the results of an experiment in which different concentrations of the
enzyme were added to tubes containing catechol solution. The tubes were kept at a constant
temperature and shaken periodically during the experiment.
The time taken for a standard brown colour to develop was recorded and from this the rate of
reaction was calculated, using
1
for the colour to develop.
time in minutes
A graph was then plotted of rate against enzyme concentration.
(a)
What general conclusion concerning enzyme action can be drawn from these results?
[1]
..............................................................................................................................
..............................................................................................................................
(b)
At what enzyme concentration would the standard colour be obtained after 18
minutes? Show your working.
[2]
..............................................................................................................................
..............................................................................................................................
GCE BIOLOGY Specimen Assessment Materials 16
(c)
Explain why the addition of lemon juice (citric acid) to the tubes stops any colour
change.
[1]
..............................................................................................................................
..............................................................................................................................
(d)
Explain what is likely to happen to the rate of colour change if the temperature of a
tube containing the enzyme polyphenol oxidase and catechol was gradually raised
from 10ºC to 100ºC.
[2]
..............................................................................................................................
..............................................................................................................................
..............................................................................................................................
..............................................................................................................................
(e)
Suggest what might happen to the rate of reaction if a competitive inhibitor was
added. Explain your answer.
[2]
..............................................................................................................................
..............................................................................................................................
..............................................................................................................................
..............................................................................................................................
(f)
'All enzymes are proteins', describe how you would test to show that polyphenol
oxidase is a protein.
[2]
..............................................................................................................................
..............................................................................................................................
..............................................................................................................................
..............................................................................................................................
(Total 10 marks)
GCE BIOLOGY Specimen Assessment Materials 17
8.
Answer ONE of the following questions.
Any diagrams included in your answer must be fully annotated.
EITHER
(a)
Distinguish between primary, secondary, tertiary and quaternary
structure of proteins.
[10]
OR
(b)
With the aid of labelled drawings, compare and contrast a
mitochondrion and a chloroplast.
[10]
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GCE BIOLOGY Specimen Assessment Materials 18
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GCE BIOLOGY Specimen Assessment Materials 19
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GCE BIOLOGY Specimen Assessment Materials 21
CYD-BWYLLGOR ADDYSG CYMRU
Tystysgrif Addysg Gyffredinol
Uwch Gyfrannol/Uwch
WELSH JOINT EDUCATION COMMITTEE
General Certificate of Education
Advanced Subsidiary/Advanced
BIOLOGY
UNIT 2
SPECIMEN PAPER
(1 hour 30 minutes)
INSTRUCTIONS TO CANDIDATES
Write your name, centre number and candidate number in the spaces at the top of this page.
Answer all questions.
Write your answers in the spaces provided in this booklet.
INFORMATION FOR CANDIDATES
The number of marks is given in brackets at the end of each question or part-question.
You are reminded that assessment will take into account the quality of written communication
used in your answers.
No certificate will be awarded to a candidate detected in any unfair practice during the
examination.
GCE BIOLOGY Specimen Assessment Materials 22
1.
The diagram shows the relationship between six different species (A, B, C, D, E and
F) which have evolved from a common ancestor.
(a)
(i)
State which two species are most closely related.
[1]
.......................... and ..........................
(ii)
Use the information in the diagram to explain why A and B are less closely
related to each other than B and C.
[1]
..................................................................................................................
..................................................................................................................
(b)
If specimens of species A, B and C had been provided instead of the diagram, how
could you tell which two were most closely related?
[1]
..............................................................................................................................
..............................................................................................................................
(Total 3 marks)
GCE BIOLOGY Specimen Assessment Materials 23
2.
(a)
Describe the digestion of carbohydrate in the alimentary canal.
[6]
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(b)
Some people continually overproduce acid in the stomach. During acid reflux, the
acidic contents of the stomach move up into the oesophagus, causing irritation and
damage to the cells lining the oesophagus. Acid reflux is one cause of 'heartburn'.
A pH probe was used to discover whether a patient's 'heartburn' was caused by acid
reflux.
This probe monitored the pH in the oesophagus from 8am to midnight. The results
are shown below.
GCE BIOLOGY Specimen Assessment Materials 24
(i)
State two functions of the acid secreted in the stomach.
[1]
..................................................................................................................
..................................................................................................................
..................................................................................................................
(ii)
Why are cells lining the stomach not affected by acid in the same way as the
cells lining the oesophagus?
[1]
..................................................................................................................
(iii)
Suggest an explanation for the pH values observed in the oesophagus up to
an hour after a meal is eaten.
[2]
..................................................................................................................
..................................................................................................................
..................................................................................................................
(Total 10 marks)
GCE BIOLOGY Specimen Assessment Materials 25
3.
An experiment was performed in which 14CO2 was applied to a single leaf of a plant kept in
the light. The distribution of the 14C throughout the plant was subsequently monitored.
The diagram shows the distribution of 14C throughout the plant (in arbitary units).
(a)
State the name of the substance in which the 14C will be transported in the stem.
[1]
.........................................................................
(b)
Explain how the results demonstrate that bi-directional flow occurs in the stem.
[2]
..............................................................................................................................
..............................................................................................................................
..............................................................................................................................
..............................................................................................................................
(c)
(i)
Explain the relatively high value of 14C found at the top of the stem.
[2]
..................................................................................................................
..................................................................................................................
..................................................................................................................
..................................................................................................................
(ii)
State the general name given to areas which unloading of carbohydrate
occurs.
[1]
.........................................................................
(Total 6 Marks)
GCE BIOLOGY Specimen Assessment Materials 26
4.
(a)
The following diagram shows blood pressure changes as blood travels through one
circuit of the circulatory system.
(i)
Explain fully the reasons for the alternating high and low blood pressure in
region A.
[4]
..................................................................................................................
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..................................................................................................................
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(ii)
Why does the blood pressure decrease so rapidly in region B.?
[1]
..................................................................................................................
..................................................................................................................
(b)
Why is it important that the blood pressure in the lung capillaries is lower than that in
the body capillaries?
[1]
..............................................................................................................................
..............................................................................................................................
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GCE BIOLOGY Specimen Assessment Materials 27
(c)
There is a difference between the arterial pressures and the capillary pressures.
Explain, in relation to the functions of these vessels, why this is more efficient. [4]
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(d)
Give one reason to explain how a return flow to the heart is possible when the vein
pressures are so low.
[1]
..............................................................................................................................
..............................................................................................................................
(e)
The diagrams represent sections through the hearts of a fish (lateral view) and a
mammal (ventral view).
Write the sequence of letters which indicates decreasing levels of maximum pressure
in the regions of the heart of the
[1]
fish ....................................................................................................................
mammal ............................................................................................................
GCE BIOLOGY Specimen Assessment Materials 28
(f)
Suggest two advantages of a double circulation system.
[2]
............................................................................................................................
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(Total 14 Marks)
GCE BIOLOGY Specimen Assessment Materials 29
5.
(a)
Single celled organisms such as Amoeba rarely exceed 500μm in diameter. Suggest
two reasons, giving a brief explanation for each, why the size of such organisms
rarely exceeds this.
[2]
1.
..................................................................................................................
..................................................................................................................
..................................................................................................................
2.
..................................................................................................................
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(b)
Give three adaptations for gas exchange which are shown by an earthworm.
1.
[3]
..................................................................................................................
..................................................................................................................
2.
..................................................................................................................
..................................................................................................................
3.
..................................................................................................................
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(c)
Most fish have a counter current system operating in the gills.
(i)
What is meant by the term counter current as used in the above statement?[1]
..................................................................................................................
..................................................................................................................
..................................................................................................................
(ii)
Explain the advantage to the fish of having a counter system in the gills.
[2]
..................................................................................................................
..................................................................................................................
..................................................................................................................
..................................................................................................................
(d)
Both fish and mammals have ventilation mechanisms.
Explain the function of ventilation mechanisms.
............................................................................................................................
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............................................................................................................................
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[2]
GCE BIOLOGY Specimen Assessment Materials 30
(e)
The diagram below compares a normal spirometer trace with one from a trained
athlete and one from an asthma sufferer.
(i)
What feature shows the effect of training on the trace obtained from the
athlete?
[1]
............................................................................................................................
(ii)
What additional feature distinguishes the asthma sufferer's trace from the
other traces and explain the cause of this feature.
[2]
............................................................................................................................
............................................................................................................................
............................................................................................................................
(f)
Carbon dioxide in the exhaled gases is removed by passing the gases through soda
lime or carbosorb before they are returned to the spirometer. Explain why the carbon
dioxide levels in the blood would rise if the carbon dioxide in the exhaled gases was
not removed.
[2]
..............................................................................................................................
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(g)
Explain why the spirometer cannot be used to measure the total capacity of the lungs.
[2]
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(Total 17 Marks)
GCE BIOLOGY Specimen Assessment Materials 31
6.
The graph shows changes in the mean stomatal pore size on leaves of a plant subjected to
natural light from the window of a laboratory for a 24 hour period.
(a)
What effect does light have on the pore size?
[1]
.........................................................................................................................................
(b)
A computer simulation was used to predict the effect of different pore sizes on
transpiration rate, at two different air speeds. The following results were obtained:
-2
Mean pore size / µm
(i)
Transpiration rate / µgh-1
air speed = 1 ms-1
air speed = 20 ms-1
40
100
480
80
100
720
120
110
880
160
120
980
200
120
1060
Using the information, suggest how increasing pore size will affect
transpiration rate.
[1]
............................................................................................................................
............................................................................................................................
(ii)
Explain why the results are different at low and high air speeds.
[2]
............................................................................................................................
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GCE BIOLOGY Specimen Assessment Materials 32
(c)
In an experiment, a well watered plant was placed near the window of a laboratory.
A fan was arranged to give a constant air speed of 20 ms-1. Measurements of
transpiration rate were started at dawn and continued for 24 hours.
(i)
Using information from parts (a) and (b), describe how you would expect the
transpiration rate to change over the period of the experiment.
[4]
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(ii)
Describe a suitable control for the experiment, which would help to show that
the results are due to the effect of light on the plant.
[2]
............................................................................................................................
............................................................................................................................
............................................................................................................................
(Total 10 Marks)
GCE BIOLOGY Specimen Assessment Materials 33
7.
Answer one of the following questions.
Any diagrams included in your answer must be fully annotated.
Either, (a)
Or
(b)
(i)
Explain the advantages of asexual reproduction in plants.
(ii)
Explain the ways in which the reproduction and dispersal of
flowering plants show adaptations for life on land.
[10]
(i)
Explain, giving suitable examples, what is meant by the terms
complete and incomplete metamorphosis.
(ii)
Explain why insects have been successful in colonising land.
[10]
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GCE BIOLOGY Specimen Assessment Materials 35
CYD-BWYLLGOR ADDYSG CYMRU
Tystysgrif Addysg Gyffredinol
Uwch
WELSH JOINT EDUCATION COMMITTEE
General Certificate of Education
Advanced
BIOLOGY
UNIT 4
SPECIMEN PAPER
(1 hour 45 minutes)
INSTRUCTIONS TO CANDIDATES
Write your centre number, name and candidate number in the spaces provided above.
Answer all questions.
Write your answers in the spaces provided in this booklet.
INFORMATION FOR CANDIDATES
The number of marks is given in brackets at the end of each question or part-question.
You are reminded that assessment will take into account the quality of written communication
used in your answers.
No certificate will be awarded to a candidate detected in any unfair practice during the
examination.
GCE BIOLOGY Specimen Assessment Materials 36
1.
Whitefly is a typical greenhouse pest that affects many crops. Treatment against this pest can
be chemical control by the use of pyrethroids, or biological control by use of the parasitic
wasp Encarsia formosa.
(a)
State what is meant by the term parasite.
[2]
.........................................................................................................................................
.........................................................................................................................................
(b)
State one advantage of the use of chemical control of pests such as whitefly.
[1]
.........................................................................................................................................
.........................................................................................................................................
(c)
The following information is provided by a manufacturer who supplies Encarsia
formosa to growers to control whitefly:
•
At a temperature below 18ºC the parasitic wasps are almost unable to fly and
their searching ability is seriously limited.
•
Certain pesticides (e.g. pyrethroids) can have a long residual effect on
Encarsia.
•
As whitefly populations develop, the leaves of the crop become coated with
their sticky excreta (honeydew) and this hampers the mobility of Encarsia.
Using the manufacturer's information and your knowledge:
(i)
Give two reasons why it would not be appropriate to use both chemical
(pyrethroids) and biological (Encarsia formosa) to control whitefly, at the
same time.
[2]
..................................................................................................................
..................................................................................................................
..................................................................................................................
(ii)
Suggest why the use of Encarsia formosa would not be effective if whitefly
attacked crops in fields in the UK.
[3]
..................................................................................................................
..................................................................................................................
..................................................................................................................
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GCE BIOLOGY Specimen Assessment Materials 37
(ii)
Explain why the late application reduces the effectiveness of Encarsia
formosa.
[1]
..................................................................................................................
..................................................................................................................
(d)
Certain ornamental plants must be grown in a completely pest free environment.
Suggest why Encarsia formosa could not be used to achieve this situation.
[1]
..............................................................................................................................
..............................................................................................................................
(Total 10 Marks)
GCE BIOLOGY Specimen Assessment Materials 38
2.
(a)
Suggest how you could ensure that aseptic and sterile conditions are present during
the preparation of agar plates and the transfer of the bacteria from the culture medium
to the plates.
[3]
..............................................................................................................................
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(b)
Some substances are know to interfere with the action of antibiotics and are called
antagonist. Two strips of filter paper, one soaked with the antibiotic and the other
soaked with a suspected antagonist, are placed so that they cross at right angles on a
Petri dish. The Petri dish contains nutrient agar inoculated with a microorganism
sensitive to the antibiotic. Draw and label on the diagram the pattern of bacterial
growth you would expect to see after 48 hours incubation.
[2]
GCE BIOLOGY Specimen Assessment Materials 39
(c)
Three students were carrying out an experiment in which bacteria were cultured in a
liquid. A sample of the bacteria was stained purple by the Gram stain.
(i)
What does the staining indicate about the structure of the bacterial cell wall?
[2]
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(ii)
Often a culture must be diluted before a count can be made of the numbers of
organisms present.
The diagrams below show how a dilution was carried out and the result of
incubating 1cm3 of the diluted sample on a nutrient agar plate for 24 hours.
GCE BIOLOGY Specimen Assessment Materials 40
Using this information, complete the dilution factors and calculate the
estimated total population in 1cm3 of the original culture.
Show your working.
[3]
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(Total 10 Marks)
GCE BIOLOGY Specimen Assessment Materials 41
3.
The table shows the velocity of impulse conduction in the nerves of various animals.
Temperature
ºC
Fibre
diameter (µm)
Impulse
velocity (ms-1)
Squid giant axon (unmyelinated)
20
500
25
Crab (unmyelinated)
20
20
5
Prawn (unmyelinated)
20
35
15
Frog (myelinated)
24
14
26
Cat (myelinated)
38
18
98
Cat (unmyelinated)
38
1.5
2.1
(a)
(i)
Comment on the impulse velocity along myelinated and unmyelinated fibres.
[1]
..................................................................................................................
..................................................................................................................
(ii)
State how the velocity of an impulse is influenced by the diameter of the fibre
along which it travels.
[1]
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(iii)
Explain how you deduced this relationship from the data in the table.
[2]
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(b)
Explain fully why the conclusions may not be valid.
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[2]
GCE BIOLOGY Specimen Assessment Materials 42
(c)
The graph shows tracings, obtained at three different temperatures, by electrically
stimulating the nerve supplying frog muscle.
(i)
State three effects of temperature on the contraction of the muscle after
stimulation.
[3]
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(ii)
Suggest an explanation for these effects.
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[2]
GCE BIOLOGY Specimen Assessment Materials 43
(d)
"Donepezil is an oral medication used to treat Alzheimer's disease, the progressive
disease of the brain that leads to nerve cell death and in turn, causes deficits in the
neurotransmitters. It belongs to a class of drugs called cholinesterase inhibitors,
because it acts as a competitive inhibitor of acetylcholinesterase.".
(i)
Suggest why donepezil might alleviate some of the symptoms of Alzheimer's
disease.
[1]
..................................................................................................................
..................................................................................................................
(ii)
Explain the mechanism of competitive inhibition.
[3]
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(Total 15 Marks)
GCE BIOLOGY Specimen Assessment Materials 44
4.
Diagrams of the nephrons from the kidneys of three different mammals are shown below.
GCE BIOLOGY Specimen Assessment Materials 45
(a)
(i)
Suggest the relationship between the length of part D and the water potential
(concentration) of the urine in the mammals, X, Y and Z.
[1]
..................................................................................................................
(ii)
Explain how structure D affects the water potential of urine.
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[5]
GCE BIOLOGY Specimen Assessment Materials 46
(b)
The graphs below show how the hydrostatic and osmotic pressures change in the
blood supply to a nephron.
(i)
Through which type of blood vessel is the greatest drop in hydrostatic
pressure?
[1]
.........................................................................................
(ii)
Explain the drop in hydrostatic pressure as the blood flows into the
peritubular capillaries.
[1]
..................................................................................................................
(iii)
The walls of the capillaries are permeable to fluids.
capillaries named in the graph will fluid move out?
In which of the
[1]
.........................................................................................
(iv)
Using the terms hydrostatic pressure and osmotic pressure explain why fluid
moves out of these vessels.
[1]
..................................................................................................................
..................................................................................................................
GCE BIOLOGY Specimen Assessment Materials 47
(c)
Nitrogenous waste in animals may occur as ammonia, urea, or uric acid. Ammonia is
very soluble and highly toxic; urea is soluble and mildly toxic; uric acid is insoluble
and non-toxic. The table shows the percentages of these three compounds in the
urine of four different animals.
Fresh water fish
Sea water fish
Lizard
Bird
(i)
Ammonia
Urea
Uric acid
56
7
0
3
6
81
0
4
0
0
91
72
Give an explanation for the difference in the main excretory compound in
fresh water and sea water fish.
[4]
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(ii)
Both lizards and birds are terrestrial, egg-laying animals. How do these
characteristics relate to the nature of their main excretory products?
[2]
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(Total 16 Marks)
GCE BIOLOGY Specimen Assessment Materials 48
5.
ATP is a compound that is described as the universal energy currency in living organisms.
(a)
(i)
Using the structure of ATP, explain what is meant by the phrase energy
currency.
[5]
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(ii)
Give two examples of the use of ATP.
[1]
.........................................................................................
........................................................................................
(b)
A diagram summarising the role of the electron transport system in ATP production is
shown below.
This process takes place during both respiration and photosynthesis.
GCE BIOLOGY Specimen Assessment Materials 49
State the electron donor (X) and the final electron acceptor (Y) during
(i)
respiration;
[2]
X .........................................
Y .........................................
(ii)
photosynthesis.
[2]
X .........................................
Y .........................................
(c)
As the electron is transferred along the electron transport chain, energy is made
available for ATP formation.
Explain how this energy is used to produce ATP.
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[4]
GCE BIOLOGY Specimen Assessment Materials 50
(d)
Dinitrophenol is a chemical which was used in the manufacture of explosives during
the First World War but it poisoned some of the workers. If dinitrophenol is absorbed
into the body it reduces the quantity of ATP produced by the electron transport chain.
The electron transport chain continues but most of the energy released is in the form
of heat. Explain why people suffering from dinitrophenol poisoning experience
symptoms such as lack of energy and weight loss.
[4]
..............................................................................................................................
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(Total 18 Marks)
GCE BIOLOGY Specimen Assessment Materials 51
6.
Answer one of the following questions.
Any diagrams included in your answer must be fully annotated.
Either, (a)
Describe the light-independent stage (Calvin cycle) of photosynthesis.
Indicate the possible fate of the products of this process.
[11]
Or
(i)
Explain why nitrogen is important to living organisms.
(ii)
Give an account of the different bacteria and their importance in the
nitrogen cycle and soil fertility.
[11]
(b)
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GCE BIOLOGY Specimen Assessment Materials 52
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GCE BIOLOGY Specimen Assessment Materials 53
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GCE BIOLOGY Specimen Assessment Materials 55
CYD-BWYLLGOR ADDYSG CYMRU
Tystysgrif Addysg Gyffredinol
Uwch
WELSH JOINT EDUCATION COMMITTEE
General Certificate of Education
Advanced
BIOLOGY/HUMAN BIOLOGY
UNIT 5
SPECIMEN PAPER
(1 hour 45 minutes)
INSTRUCTIONS TO CANDIDATES
Write your centre number, name and candidate number in the spaces provided above.
Answer all questions.
Write your answers in the spaces provided in this booklet.
INFORMATION FOR CANDIDATES
The number of marks is given in brackets at the end of each question or part-question.
You are reminded that assessment will take into account the quality of written communication
used in your answers.
No certificate will be awarded to a candidate detected in any unfair practice during the
examination.
GCE BIOLOGY Specimen Assessment Materials 56
1.
The diagram shows the flow of energy through an ecosystem.
(a)
The energy flow through the herbivores can be expressed by the equation:
C1 = C2 + R2 + E2
(i)
Calculate the respiratory loss by the herbivores and write your answer in the
correct position on the diagram.
[1]
(ii)
Give the equation that expresses the energy flow through the carnivores. [1]
..................................................................................................................
(b)
The values given are for a small wood and are in kJm-2yr-1. The area of wood is
25 000 m2.
(i)
Calculate the total amount of energy 'expelled' by this ecosystem in one year,
showing your workings.
[2]
..................................................................................................................
..................................................................................................................
..................................................................................................................
(ii)
Describe what happens to this 'expelled' energy.
[2]
..................................................................................................................
..................................................................................................................
..................................................................................................................
(Total 6 marks)
GCE BIOLOGY Specimen Assessment Materials 57
2.
In Africa, Lake Nabugabob separated from Lake Victoria thousands of years ago. There are
five species of cichlid fish of the genus Haplochromis in Lake Nabugabob, each descended
from a different species in the main lake, Lake Victoria.
(a)
Suggest how analysis of DNA or proteins might be used to supply additional
evidence that the Lake Nabugabob fish have descended from ancestors in Lake
Victoria.
[2]
.........................................................................................................................................
.........................................................................................................................................
.........................................................................................................................................
.........................................................................................................................................
(b)
Explain how the splitting of the fish population into Lake Nabugabob and Lake
Victoria populations has led to the formation of the separate species.
[6]
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(Total 8 marks)
GCE BIOLOGY Specimen Assessment Materials 58
3.
Duchenne muscular dystrophy (DMD) is a generative muscular disease. It is caused by a sexlinked recessive allele. A family pedigree showing inheritance is shown below.
(a)
Fully explain the term sex-linked recessive allele.
[4]
.........................................................................................................................................
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.........................................................................................................................................
.........................................................................................................................................
.........................................................................................................................................
(b)
Use the key below to answer the following questions.
KEY:
(i)
XN
Normal allele
Xn
Muscular dystrophy allele
Y
Male chromosome
The probable genotype of A, B, C and D is
[1]
…………………………………………….
(ii)
The genotype of E, F and G is
[1]
……………………………………………..
(iii)
Give the genotype of all the normal males.
…………………………………………….
[1]
GCE BIOLOGY Specimen Assessment Materials 59
(c)
(d)
Complete the genetic diagram to show the mechanism by which E inherited the
disease.
[4]
Parents
Male
X
Female
Genotype
………….
………….
Gametes
…… ……
…… ……
Offspring Genotypes
………….
………….
………….
………….
Corresponding
Offspring Phenotypes
………….
………….
………….
………….
Discuss an argument for and an argument against the screening of apparently normal
individuals for genetic disorders.
[2]
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(Total 13 marks)
GCE BIOLOGY Specimen Assessment Materials 60
4.
During protein synthesis, amino acids are carried by tRNA. Each amino acid is first joined to
its tRNA by an enzyme. The diagram below shows the stages in this process.
(a)
(i)
What is the name given to the region consisting of ABC?
[1]
.....................................................................
(ii)
The shape of the enzyme molecule partly depends upon different types of
bond. Name two of these bonds.
[2]
..................................................................................................................
..................................................................................................................
The diagram below represents a stage in the synthesis of the polypeptide chain.
(b)
Name
(i)
the organelle labelled C,
[1]
.......................................................................
(ii)
the structure labelled D,
.......................................................................
[1]
GCE BIOLOGY Specimen Assessment Materials 61
(c)
The process shown arranges the correct sequence of amino acids in the peptide.
(i)
Name this process.
[1]
.......................................................................
(ii)
Explain what ensures that the correct amino acid is added.
[3]
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(d)
After the stage shown, explain what happens to A and B.
[3]
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(e)
It is important that this whole process is carried out correctly.
Explain why.
[2]
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(Total 14 marks)
GCE BIOLOGY Specimen Assessment Materials 62
5.
The following diagram is a simplified representation of a technique used in genetic
engineering.
GCE BIOLOGY Specimen Assessment Materials 63
(a)
Suggest why the same enzyme (enzyme A) is used to cut both the vector DNA and
the chromosomal DNA fragment.
[2]
.........................................................................................................................................
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(b)
What is the function of enzyme B?
[1]
.........................................................................................................................................
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(c)
Describe two ways in which the chromosomal DNA fragment can be obtained.
[3]
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(d)
Trials have been done to genetically modify cauliflowers to make their leaves much
greener than normal. 'Green genes' were introduced into cauliflower cells by either
attaching them to part of a cauliflower virus (which has been rendered harmless) or to
a bacterial plasmid. Suggest two reasons why there are concerns about this
technology.
[2]
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GCE BIOLOGY Specimen Assessment Materials 64
(e)
Recent progress has been made towards effective treatment for cystic fibrosis. The
key problem remains developing an effective delivery system to introduce the
replacement gene into the cells. One delivery system is a virus which is known not to
cause disease in humans.
(i)
What are the two major components of a virus?
[1]
........................................................................
........................................................................
(ii)
Briefly describe another delivery system which could be used to introduce the
gene to the lung cells.
[3]
..................................................................................................................
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(iii)
Which events must occur once the replacement gene is inside the lung cell for
the treatment to be successful?
[3]
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(Total 15 marks)
GCE BIOLOGY Specimen Assessment Materials 65
6.
The cultivated banana is sterile and seedless. It reproduces asexually, producing shoots or
suckers that develop into new plants. It is extremely difficult to develop disease-resistant
varieties of this plant.
In the 1950s the main variety grown in banana plantations was Gros Michel. This variety was
totally wiped out by Panama disease, caused by a soil fungus (Fusarium oxysporum). The
disease spread rapidly from one plant to another and from plantation to plantation.
Following the devastation, a variety of banana that was resistant to Panama disease,
Cavendish, was planted and has been used ever since. However, it became apparent that
Cavendish was susceptible to the disease Sigatoka, caused by another fungus
(Mycosphaerella fijiensis). Only the use of massive amounts of fungicide spray is keeping
Sigatoka under control. It seems that as soon as a new fungicide is used that fungus develops
resistance to it.
(a)
(i)
State the genus of the fungus that causes Panama disease.
[1]
..........................................................................
(ii)
Explain why Panama disease spread so quickly through the banana
plantations and wiped out the Gros Michel variety in the 1950s.
[3]
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………
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(b)
Explain how the fungus that causes Sigatoka becomes resistant to fungicides.
[7]
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GCE BIOLOGY Specimen Assessment Materials 66
(c)
Explain why it is so difficult to develop disease-resistant varieties of banana.
[3]
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(Total 14 marks)
GCE BIOLOGY Specimen Assessment Materials 67
8.
Answer one of the following questions.
Any diagrams included in your answer must be fully annotated.
Either, (a)
Give an account of the steps involved in cloning plants and mammals.
Describe one advantage and one disadvantage of these techniques.
or
Man has been accused of rape of the land and the sea and with agricultural
exploitation.
What are the consequences of:
(b)
(i)
(ii)
[10]
forest destruction
fishing.
What should be done to allow sustainability of both these resources?
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[10]
GCE BIOLOGY Specimen Assessment Materials 68
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GCE BIOLOGY Specimen Assessment Materials 69
MARK SCHEMES
GCE BIOLOGY Specimen Assessment Materials 71
STRICTLY CONFIDENTIAL
WELSH JOINT EDUCATION COMMITTEE
CYD-BWYLLGOR ADDYSG CYMRU
MARK SCHEME
COVER SHEET
AS/A2 UNITS
NOTES
Assistants are asked to read and digest thoroughly all the information set out in the document
"Instructions for Examiners". It is essential for the smooth running of the examination that these
instructions are adhered to by all. Particular attention should be paid to the following instructions
regarding marking:
1.
The markscheme indicates the central information required to access the mark. However
points, particularly in extended prose answers, should be made in the correct context and
expanded sufficiently beyond a basic phrase or term in order to provide a complete and
coherent answer to the question asked including relevant explanation of the points being
made.
2.
Compliance with the mark scheme is required of all assistants in order to ensure
comparability. The mark scheme shows a variety of suitable correct answers to the questions.
Over-rigidity in its interpretation is not intended and it is accepted that points may be made in
a variety of different ways to include converse and counterpoints. Thus, except where terms
are specifically requested, all correct responses even if expressed using different words are
acceptable provided the points are explicit, unambiguous and made in the correct context. If
the meaning is unclear then the mark cannot be awarded.
3.
Marking is to be carried out with a red ballpoint or felt-tip pen. The ticks are to be placed on
the word or phrase which qualifies for the mark.
4.
Sub-totals in the margins must clearly be seen to be the sum of ticks within the script and all
questions should show evidence of marking. The total for the question should be written at
the end of the question. Transfer each checked total to the front cover.
GCE BIOLOGY Specimen Assessment Materials 73
UNIT 1: BIOLOGY/HUMAN BIOLOGY
MARK SCHEME
1.
Monosaccharide
Glucose is an
example of
Disaccharide
Structural
Polysaccharide
Storage
Polysaccharide
[1]
9
Cellulose is an
example of
[1]
9
Amylose is an
example of
9
Maltose is an
example of
[1]
9
9
Insoluble
Deoxyribose is an
example of
[1]
9
9
[1]
[1]
(Total 6 Marks)
2.
(a)
A
B
Pentose sugar / deoxyribose (allow: 5 carbon sugar)
Phosphate
[1]
(b)
Hydrogen (Bonding) (not: H)
[1]
(c)
(i)
Purine
[1]
(ii)
C Adenine
D Thymine [allow a consequential error here]
[1]
[1]
Reject abbreviations A/T / consequential error if C is uracil.
(d)
Ring should cover any 1 base with 1 sugar and 1 phosphate (through dotted lines
i.e, bond)
[1]
(e)
If 28% G then C must be 28%
[1]
(28+28 = 56) / 100 − 56 = 44/(A+T = 44)
[1]
T = 22(%)
[1]
1 mark for each correct line.
(Total 9 Marks)
GCE BIOLOGY Specimen Assessment Materials 74
3.
(i)
{very little increase/0-7 units} up to {40ºC/first 4 temperatures;
rapid rise at 50ºC/rise from 7 to 80 at 50ºC;
small rise from 80 to 100 units from 50 to 70ºC
higher temperature, darker solution/higher reading
(ii)
[2]
Membrane (proteins) are stable between 10 and 40ºC/at low temperatures;
(Appearance of the red pigment means that) the (tonoplast and) cell membrane has
been damaged between 40 and 50ºC/at high temperatures;
(meaning) pigment has leaked out of cells/sap vacuole/change in membrane
permeability/damaged membrane;
(iii)
proteins change shape/denature and come out of bilayer;
[3]
Dissolves phospholipids/destroys cell membrane structure;
[1]
(So) pigment leaks out.
(not: ref. to higher or lower readings)
[1]
(Total 7 Marks)
4.
(a)
6.5
[1]
(b)
(i)
A
[1]
the greatest volume of oxygen produced in unit time / reference to minutes [1]
(ii)
E
[1]
the greatest number of substrate / hydrogen peroxide molecules have been
broken down to produce the oxygen / all the enzyme active sites are
occupied.
[1]
(c)
A change in pH in the environment of the active site alters the ionic charge of the
acidic and basic groups of the amino acids
and causes the shape of the protein to change.
This may prevent the substrate molecules from making a close fit to the active site.
[3]
(d)
The slight reaction is due to the decomposition of hydrogen peroxide in air.
(e)
(The substrate concentration is constant)
Use the optimum pH value
[1]
Vary the concentration of catalase by dilution of minced liver / changing the mass of
the minced liver added.
[1]
[1]
(Total 11 Marks)
GCE BIOLOGY Specimen Assessment Materials 75
5.
(a)
(i)
(ii)
2(mm)
(because) it gives the highest percentage of product
(not: converse)
[1]
smaller beads give a larger total area (exposed to the milk / substrate);
(not: smaller beads have large surface area)
OR
smaller beads will pack more closely (so there is more enzyme:substrate);
the milk will have longer contact / flow more slowly around small, close
packed beads;
OR
gives more time for the enzyme and substrate to come into contact
(iii)
(iv)
(b)
[2]
Percentage product would increase / get more product;
More time for enzyme-substrate complexes to occur / for reaction.
[2]
temperature / milk type / source (not: pH)
[1]
Can tolerate / more stable in a wider range of condition / temps / pH qualified;
Product not contaminated with enzyme / pure product / easily reused qualified;
Several enzymes (requiring different conditions) may be used together;
Enzymes easily added / removed = more control.
(allow: ref. to continuous production qualified,
(not: ref. to cost)
[2]
(Total 8 Marks)
GCE BIOLOGY Specimen Assessment Materials 76
6.
(a)
(b)
12 single structures (chromosomes);
[1]
Separated from each other;
[1]
Labels: centrioles, spindle fibres, centromere, chromosomes
Max 2 for any 3 labels.
[2]
replication of DNA must take place;
Centrioles replicate;
Organelles e.g. mitochondria are produced;
Protein synthesis occurs;
RNA / nucleotide synthesis occurs;
High rate respiration / ATP synthesis is needed;
AVP. e.g. Two chromatids formed.
(Max. 5) (not: growth)
[5]
(Total 9 Marks)
7.
(a)
As the concentration increased the rate of reaction increased.
[1]
(b)
5.5; (allow : 5.6)
[1]
Fig. from graph (1.1 to 1.2)
[1]
(c)
Enzyme has a pH optimum / does not work in acid pH caused by lemon juice
(allow: denatured not: destroyed / inhibited)
[1]
(d)
Faster (colour change) at start as temperature increases;
[1]
No further colour change after enzyme denatured.
[1]
rate drops / stops if all active sites blocked;
[1]
as it competes with normal substrate for active sites.
[1]
Biuret test / NaOH or any alkali plus CuSO4;
[1]
Purple / violet ring / colour develops if protein.
(linked marks)
[1]
(e)
(f)
(Total 10 Marks)
GCE BIOLOGY Specimen Assessment Materials 77
8.
(a)
A
Primary is (type, number and) sequence / order of amino acids
[1]
B
linked by peptide bonds
[1]
C
Secondary is (3D) folding / most common is (α) helix / β pleated sheet
[1]
D
formed by hydrogen bonds (between peptide bonds)
[1]
E
Tertiary is folding / twisting of a α helix / structure
[1]
F
(As shown by) globular proteins
[1]
G
To form very specific (3D) shapes
[1]
H
R groups project from α helix / side chains / part of active site
(i.e. function of R groups)
[1]
I
And may react to form bonds which stabilise 3D shape
(i.e. side chains)
[1]
J, K
Any two from, covalent / disulphide bridges; ionic / salt bridges;
hydrogen bonds; hydrophobic bonds.
[1]
L
Quaternary is two or more polypeptide / amino acid chains.
[1]
M
Joined by similar bonds between projecting R groups.
(i.e. named bond between R groups)
[1]
N
e.g. Haemoglobin.
[1]
O
Fibrous proteins have helices linked in strands.
(Maximum 10 from available 15)
[1]
(Total 10 Marks)
GCE BIOLOGY Specimen Assessment Materials 78
(b)
A
Mitochondrion has double / inner and outer membrane.
[1]
B
with narrow fluid filled Inter-membrane space between.
[1]
C
cristae / stalked particles are infoldings of the inner membrane.
[1]
D
the interior contains an organic matrix.
[1]
E
DNA / ribosome present (in either mitochondrion or chloroplast).
[1]
F
and the organelles are self replicating (either mitochondrion or chloroplast).
[1]
G
The function is energy release / ATP production / aerobic respiration.
[1]
H
Chloroplast has double / inner and outer membrane.
[1]
I
interior of the chloroplast is the gelatinous stroma.
[1]
J
Flattened sacs / lamellae / thylakoids are present in the stroma.
[1]
K
usually (stacked to form) grana.
[1]
L
sites of photosynthetic pigments / chlorophyll
e.g. grana, thylakoids
[1]
M
Starch grains may be present.
[1]
N
Chloroplast function is photosynthesis.
[1]
O
Some attempt at genuine comparison.
(Maximum 10 from available 15)
[1]
Any 9 points plus point O.
(Total 10 Marks)
GCE BIOLOGY Specimen Assessment Materials 79
WELSH JOINT EDUCATION COMMITTEE
CYD-BWYLLGOR ADDYSG CYMRU
General Certificate of Education
Tystysgrif Addysg Gyffredinol
MARK SPECIFICATION GRID
GCE BIOLOGY
UNIT TEST
Year of Examination ____Specimen______
Page__1____of_____1__
Session: summer/winter
Unit _BY1_
Assessment Objective
Paper
Other requirements
Total
Mark
Question
Number
Target Totals
AS BY1, BY2
A2 BY4, BY5
Specification
Reference
AO1
AO2
AO3
33
30
33
45
4
5
70
80
Synoptic
Quality of
written
com'cn.
N/A
9
9
9
1
1.1b
5
1
6
2
1.6 a&b
5
4
9
3
1.3a
3
4
7
9
4
1.4b
1
7
3
11
9
5
1.5a
3
4
1
8
6
1.7a
5
4
9
7
1.4c
3
7
10
8
1.1d/1.2a
7
3
10
32
34
Raw Totals:
4
70
9
9
GCE BIOLOGY Specimen Assessment Materials 81
UNIT 2: BIOLOGY
MARK SCHEME
1.
(a)
(b)
(i)
D and E.
[1]
(ii)
Ancestors of A and B diverged longer ago than B and C.
[1]
Those most closely related would have more characteristics in common.
(allow: explanation in terms of phenotype / DNA fingerprinting)
[1]
(Total 3 Marks)
2.
(a)
Digestion takes place in the mouth and duodenum/small intestine;
Amylase secretion in saliva and from pancreas;
amylase converts starch to maltose;
maltase converts maltose to glucose;
sucrase converts sucrose to glucose and fructose;
digestion of disaccharides to monosaccharides occurs in or on epithelial cells;
ref. hydrolysis.
[Max. 6]
(b)
(i)
disinfectant/kills bacteria;
optimum pH/correct pH;
activation of enzymes/named enzyme;
(not: stops amylase action) Any 2.
[1]
(ii)
covered with mucus/alkaline layer.
[1]
(iii)
food (and acid) remain in stomach / acid contents being mixed
with food for 2-4 hours;
more acid production stimulated once food in stomach;
pH falls as more acid moves up into oesophagus.
Max. 2
(Total 10 marks)
3.
(a)
sucrose
(not: sugar(s) / water)
[1]
(b)
14
[1]
[1]
(c)
(i)
C at top of stem / 14C in roots
but absorbed at leaf halfway up stem
(ii)
growing point / growth
active process / ATP required / energy required
respiration / carbohydrate in respiratory substrate
(Any 2)
[2]
sinks
[1]
(Total 6 Marks)
GCE BIOLOGY Specimen Assessment Materials 82
4.
(a)
(i)
(ii)
Contraction of ventricles causes a surge in blood pressure
This drops when the ventricles relax
But does not fall to zero because of the closing of the semi-lunar valves
The elastic recoil of the arteries maintains blood pressure.
[4]
Arteries are dividing up (into arterioles) with a larger surface area/blood is
distributed in larger number of blood vessels with greater S.A./greater
resistance due to larger S.A./more friction/distance from heart greater.
[1]
(b)
(Interstitial) fluid in the lungs must not build up as this reduces the efficiency of
gaseous exchange/fluid leaks out of capillaries and fills lungs.
[1]
(c)
(i)
(d)
Any comment on the suction effect of relaxing heart/the massaging effects of
muscles/the prevention of backflow by valves.
[1]
(e)
1 fish C B A;
2 mammal F E D.
[1]
separate circulation to lungs;
maintains high pressure to body.
[2]
(f)
The arteries function is transport
which is efficient at high speed, i.e. high pressure.
Capillary function is exchange
requiring slow speed (longer contact with surroundings) and therefore lower
pressure.
[4]
(Total 14 Marks)
GCE BIOLOGY Specimen Assessment Materials 83
5.
(a)
Surface area not increasing at same rate as volume, volume of cytoplasm related to
rate of use of oxygen and nutrients, surface area related to rate of uptake by
diffusion/SA: vol ratio not enough;
maximum rate of diffusion of materials through cytoplasm/distance;
Accept reference to nucleus.
not able to exchange enough as it gets bigger.
(Allow: support qualified)
Any two.
(b)
[2]
Large surface area;
moist skin/surface
blood supply close to surface;
rich/well developed capillary network in skin/good blood supply at surface/skin
haemoglobin.
(c)
Any three.
[3]
(i)
Blood and water flow in opposite directions.
[1]
(ii)
More efficient exchange of gases/constant diffusion/exchange across whole
lamella.
Concentration gradient maintained.
(d)
(e)
[2]
Move respiratory medium over respiratory surface/bring in oxygen/remove CO2. [1]
To maintain concentration gradient.
[1]
(i)
Bigger vital capacity.
(not: description; term needed)
[1]
(ii)
Flow rate decreased as air is expelled / more difficult to breathe out) /
reference to time.
[1]
(not: reference to height of peaks)
because constriction / inflammation (of the lining) of the bronchii restricts
flow.
[1]
(not: ref. to trachea)
(f)
high/increased levels of carbon dioxide in inhaled air;
Lower concentration gradient between blood and alveolar air;
Slower diffusion;
(g)
[Max. 2]
Total capacity includes residual volume / some air always remains in the lungs /
doesn't move.
[1]
Spirometer only measures movements of air in and out / the trace only records
movements.
[1]
(Total 17 Marks)
GCE BIOLOGY Specimen Assessment Materials 84
6.
(a)
Light increases pore size.
[1]
(b)
(i)
It will increase (transpiration rate.)
[1]
(ii)
At low air speeds a layer of saturated air reduces water potential gradient
between inside and outside.
[1]
/ reverse argument / at faster air speed evaporation is faster / water molecules
removed more quickly / increases diffusion or concentration gradient.
[1]
(c)
(i)
The rate will increase at first;
it will level out (at its maximum) and remain so until dusk / dark / specified
time;
it will decrease (over the next hour / 2 hours);
it will continue at this low level until dawn / day light / specified time.
quantitative relationship ref. to any stage
(ii)
1 mark for each point. Four from five.
[4]
Second plant kept in dark / covered / constant light.
[1]
Other conditions/wind speed identical.
[1]
(Total 10 Marks)
GCE BIOLOGY Specimen Assessment Materials 85
7.
(a)
A
Large numbers produced
B
The plants produced are identical clones
C
which is an advantage if environment constant
D
giving quicker colonisation
E
There is a lack of waste e.g. excess pollen production
F
So greater chance of survival
G
and no dependence on insects
H
Water is not required for dispersal of spores / pollen grains.
I
Pollen grain is drought resistant.
J
with adaptations to flowers to ensure transport by wind, insects or other
animals
K
Gametes do not need to swim in liquid medium.
L
Female gametes retained prior to fertilisation.
M
Zygote develops to specialised resistant seeds.
N
Seeds resistant to unfavourable conditions e.g. drought/cold
O
which normally disperse independently of water or example.
(Total 10 marks)
(b)
A
Complete goes through distinct stages
B
involving egg stage
C
larva which is feeding stage
D
pupa where tissues reorganise
E
adult which emerges from pupa
F
suitable named example
G
incomplete has egg stage
H
no larva or pupa
I
suitable example
J
for life on land insects have developed cuticle
K
for retention / control of water
L
and legs for movement
M
wings for flying
N
tracheal system for gaseous exchange
O
development of mouth parts
(Total 10 marks)
GCE BIOLOGY Specimen Assessment Materials 86
WELSH JOINT EDUCATION COMMITTEE
General Certificate of Education
MARK SPECIFICATION GRID
GCE BIOLOGY
UNIT TEST
Year of Examination ____Specimen______
CYD-BWYLLGOR ADDYSG CYMRU
Tystysgrif Addysg Gyffredinol
Page__1____of_____1__
Session: summer/winter
Unit _BY2_
Assessment Objective
Question
Number
Target Totals
AS BY1, BY2
A2 BY4, BY5
Specification
Reference
Paper
AO1
AO2
AO3
Total
Mark
33
30
33
45
4
5
70
80
1
3
Other requirements
Synoptic
Quality of
written
com'cn.
N/A
9
9
9
1
2.1
1
1
2
2.5
6
4
10
3
2.3
2
4
6
4
2.3
7
7
14
5
2.1 + 2.2
9
7
1
17
6
2.3
1
7
2
10
9
7
2.4
6
4
10
9
32
34
Raw
Totals:
4
70
9
9
GCE BIOLOGY Specimen Assessment Materials 87
UNIT 4: BIOLOGY
MARK SCHEME
1.
(a)
an organism that feeds off another organism of a different species / host
harms host / doesn't kill host
(not: cause disease)
(Any 2)
[2]
(b)
quick acting / cheap / localised use / more efficient / effective / easy to apply /
produce
(Any 1)
[1]
(c)
(i)
(ii)
(iii)
(d)
chemicals non-specific
(chemicals) would kill wasp
long residual effects on Encarsia
waste of money
(Any 2)
[2]
cooler climate
wasp can't fly / little flying below 18ºC
would not fly to /reach more slowly, other infected plants in field
whitefly would not be killed / crops remain infected
(not: fly away)
(Any 3)
[3]
honeydew sticky so wasps can't move / fly
[1]
can't achieve this / biological control maintains low levels / specific to
whitefly
[1]
(Total 10 Marks)
GCE BIOLOGY Specimen Assessment Materials 88
2.
(a)
(b)
(c)
Autoclave / High temperatures and pressure / sterilised equipment.
Sterilise glass rod / loop etc. by flaming
Flame top of culture tube after removing lid
Lift Petri dish lid at angle / short time open
Bunsen to cause air flow.
(not: ref. to disinfect benches) (Max. 3)
[3]
1 mark for clear zone around antibiotic clearly labelled.
[1]
1 mark for shape (horizontal 'bow-tie').
[1]
(i)
(ii)
mostly peptidoglycan / thick murein layer;
carbohydrate / polysaccharide with amino acid side chains;
no lipoprotein / lipopolysaccharide.
[2]
calculation of dilution factor 10-2;
[1]
counting of colonies 7;
[1]
multiplication 700;
[1]
(allow: consequential error)
(Total 10 marks)
GCE BIOLOGY Specimen Assessment Materials 89
3.
(a)
(b)
(c)
(i)
Velocity is faster in myelinated.
[1]
(ii)
The greater the diameter the faster the impulse travels.
[1]
(iii)
Compared values for myelinated and unmyelinated.
Compared values of thick unmyelinated with thin unmyelinated.
[1]
[1]
More than one variable changed /
have not varied temp., with a single type of axon.
(i)
[2]
1. higher temperature sooner it starts contracting.
2. higher temperature the greater the contraction / shortening /
decrease in length
3. higher temperature - less time to return to normal length / relax
[3]
(d)
(ii)
ATPase / other relevant enzyme
enzyme controlled reactions are temperature dependent / correct
reference to collision theory
(Any 2)
[2]
(i)
it will prevent breakdown/slows hydrolysis of acetylcholine/
neurotransmitter
or therefore there will be a smaller deficit of neurotransmitters/more
present
[1]
(ii)
enzyme active site is specific shape
[1]
(substrate and inhibitor molecules have shapes) which both fit active
site/similar shape
[1]
bound inhibitor prevents substrate binding/competes with substrate to
bind
[1]
(Total 15 Marks)
GCE BIOLOGY Specimen Assessment Materials 90
4.
(a)
(i)
The longer the loop of Henle the lower the water potential of the urine
/ more concentrated urine / solute potential higher.
[1]
(ii)
Sodium (ions) pumped out; of ascending limb;
creates a region of low water potential around collecting ducts;
water moves out of collecting duct / descending limb;
by Osmosis;
ref. counter current.
(b)
(c)
[Max. 5]
(i)
afferent arterioles
[1]
(ii)
blood (slows as) passes from one large to many small
vessels/greater friction against walls of vessels/increased crosssectional area
[1]
(iii)
glomerular capillary
(iv)
hydrostatic pressure is high/greater than osmotic pressure/O.P.
low (not: increasing/decreasing)
[1]
[1]
(i)
Fresh water fish - tissue more concentrated than medium, water flows
by osmosis in to tissues so dilutes / ammonia is soluble.
Sea water fish - tissue less concentrated than medium, water moves out
by osmosis.
Ammonia becomes more concentrated.
Sea water fish has to produce a concentrated urine therefore
Urea is less toxic so sea water fish must convert ammonia to urea. [4]
(ii)
Insoluble products as not in water and non-toxic.
Reduced volume for eggs.
[2]
(Total 16 Marks)
GCE BIOLOGY Specimen Assessment Materials 91
5.
(a)
(i)
sugar + base + 3 phosphates or correct names;
ATP to ADP + Pi releases energy/exergonic or description;
ADP + Pi to ATP needs energy/endergonic or description;
easily reversible;
transfers energy from place of release/one molecule to energyrequiring reactions;
provides energy in 'small packets'/figure e.g. 30.6 or 3.1.
[5]
(Max. 5)
(ii)
(b)
(i)
(ii)
(c)
two of synthesis/muscle contraction/active transport/other
e.g. nerve impulses/photosynthesis etc.;
(not: movement/growth)
[1]
X
Y
H (atom)/reduce NAD/reduced FAD;
oxygen; (not water)
[1]
X
Y
chlorophyll/photosystem I or II;
chlorophyll/NADP/photosystem I;
[1]
[1]
(electron) fuels proton pump;
across membrane/into intermembrane space;
H+/protons diffuse/flow down concentration gradient;
Through ATP synthetase/stalked particles (not: ATPase);
Membrane impermeable to protons.
(Max.4)
(d)
[4]
Why person lacking energy e.g. ATP used for muscle contraction /less
absorption of food.
Food not enough to meet metabolic demands of body / named;
i.e. food broken down but not making sufficient ATP.
No excess food material to store.
Therefore respiration using body tissues / fat / protein / food stores.
AVP e.g. heat production increased metabolic rate / body respires faster to
produce ATP.
[Max. 4]
(Total 18 Marks)
GCE BIOLOGY Specimen Assessment Materials 92
6.
(a)
A
ATP, NADPH2 from light dependent stage are used.
B
Light independent stage take place in stroma of chloroplast.
C
A 5C acceptor molecule,
D
ribulose bisphosphate RUBP,
E
combines with carbon dioxide
F
catalysed by enzyme RuBisco/ref enzyme e.g. sequence of enzyme
controlled reactions.
G
(breaks down into 2 × 3C) glycerate 3 phosphate/PGA/GP.
H
(converted into 2 × 3C) triose phosphate/TP/GALP.
I
NADPH H+/reduced NADP.
J
supplies hydrogen/used for reduction.
K
ATP broken down into ADP and iP supplies energy.
(not: ATP supplies energy)
L
RuBP regenerated from TP.
M
Phosphate from ATP needed for this.
N
Products: Glucose, lipids, amino acids, chlorophyll, cellulose, starch.
Any 2 products.
O
Fate of two products qualified, e.g. glucose respired for energy
/amino acid make proteins
P
AVP e.g. balancing 6 RUBP etc./most TP to RBP some to glucose.
(Total 11 marks)
GCE BIOLOGY Specimen Assessment Materials 93
(b)
Nitrogen cycle mark scheme
(max. 6 for well annotated diagram)
A
Nitrogen is needed to synthesise amino acids (which are built
into proteins.)
B
Any sensible e.g. of protein use - antibodies/membrane
proteins/ enzymes.
C
Use of nitrogen to synthesise nucleic acids/DNA/RNA/ATP/
chlorophyll.
D
The nitrogen fixing bacteria.
E
Convert atmospheric nitrogen into nitrogen containing
compounds/ammonium/amino acids (not: nitrates).
F
This may be by free living bacteria in the soil.
G
Or by bacteria living in the root nodules of
H
Legumes/peas/beans/clover/lupins.
I
Growing these crops can improve soil fertility
J
Decomposers/putrefying/decay bacteria convert organic
nitrogen from dead organisms/ nitrogenous excretory
products/urea/uric acid.
K
Into ammonia/ammonium compounds.
L
The nitrifying bacteria convert this ammonia into nitrites.
M
And the nitrites into nitrates, which can be absorbed by plants.
(equivalent)
N
The denitrifying bacteria convert nitrates into atmospheric
nitrogen.
O
This is a problem in water logged soils since the bacteria are
anaerobic.
P
Which is why farmers drain wet land in order to increase soil
fertility.
(Total 11 marks)
GCE BIOLOGY Specimen Assessment Materials 94
WELSH JOINT EDUCATION COMMITTEE
CYD-BWYLLGOR ADDYSG CYMRU
General Certificate of Education
Tystysgrif Addysg Gyffredinol
MARK SPECIFICATION GRID
GCE BIOLOGY
UNIT TEST
Year of Examination ____Specimen______
Page__1____of_____1__
Session: summer/winter
Unit _BY4_
Assessment Objective
Paper
Other requirements
Total
Mark
AO1
AO2
AO3
33
30
33
45
4
5
Synoptic
Quality of
written
com'cn.
70
80
N/A
9
9
9
10
9
Question
Number
Target Totals
AS BY1, BY2
A2 BY4, BY5
Specification
Reference
1
4.5
2
8
2
4.4
3
6
1
10
3
4.7
3
8
4
15
9
9
4
4.6
5
11
16
9
9
5
4.3/4.2/4.1
10
8
18
9
9
6(a)+(b)
4.5/4.3
8
3
11
31
44
Raw Totals:
5
80
9
9
GCE BIOLOGY Specimen Assessment Materials 95
UNIT 5: BIOLOGY/HUMAN BIOLOGY
MARK SCHEME
1.
(a)
(b)
(i)
15576
[1]
(ii)
C2 = C3+R3+E3 / C3 = C2-(R3+E3)
[1]
(i)
total energy expelled per m2=972+3732+110+20+4834 (1)
total energy expelled = 4834 × 25000 (1) = 120,850,000 / 1.2085×108
[2]
(ii)
passes to decomposers / detritivores; respired / used / released by
decomposers; lost as heat
(Any 2) (not: eaten)
[2]
(Total 6 Marks)
2.
(a)
Reference to DNA / genetic fingerprinting / base sequencing / immunological
comparison;
Close similarities should be present between the species.
(i.e. technique and related result)
(b)
[2]
Populations physically / geographically separated (by a barrier);
Populations cannot interbreed;
Different mutations in each population;
Environmental conditions / habitats (or e.g.) differ;
Different selection pressures;
Leads to different gene pools / demes;
Leads to difference in physical characteristics / behaviour / appearance.
(i.e. change in genetics leads to change in phenotype)
Any 6 points in context.
[6]
(Total 8 Marks)
GCE BIOLOGY Specimen Assessment Materials 96
3.
(a)
carried on the sex / X chromosome;
only expressed if both chromosomes carry the allele / gene in females / homozygous;
always expressed in the male, (since Y is not homologous);
allele = different form of the same gene;
[4]
(b)
(i)
XN Xn
[1]
(ii)
Xn Y
[1]
(iii)
XN Y
[1]
(c)
[1]
[1]
Accept 1:1:1:1, but only if linked to genotype / 1:1:1:1 ratio of all four genotypes. [2]
Genotypes 1, linked phenotypes 1.
(not: ref. infected male)
(d)
Increased worry as may not develop disease / insurance company may not provide
cover / confidentiality issues / affects lifestyle choices / prevents gene being passed
on / reduces incidence of gene in population / AVP.
[2]
(Total 13 Marks)
GCE BIOLOGY Specimen Assessment Materials 97
4.
(a)
(b)
(c)
(d)
(i)
active site
[1]
(ii)
hydrogen / sulphur / peptide / ionic bond / van der Waals / disulphide bridges
(not: covalent)
[2]
(i)
Ribosome
[1]
(ii)
Anticodon
[1]
(i)
Translation
[1]
(ii)
Each type of tRNA has a specific linkage with one type of amino acid
[1]
tRNA joints to mRNA
[1]
by matching codon / anticodon
[1]
B moves into the vacant space to the right of A
and the addition of B's amino acid to the chain (removes the chain from A to B)
A is now free to move off and combine with another identical amino acid molecule
(i.e. reference to release).
B occupies position A was in / The ribosome moves one codon to the right / (mRNA
strand moves one codon to the left)
3 from 4.
[3]
(e)
The protein will only perform its function if the structure is correctly reproduced [1]
Active site altered or destroyed if amino acid sequence is changed
[1]
(not: makes the wrong protein)
(Total 14 marks)
5.
(a)
To give matching / the same (sticky) ends;
so that the vector / plasmid can join with the fragment;
Complementary bases. (not: codon)
(Any two)
[2]
(b)
Anneals / seals / splices sticky ends together.
[1]
(c)
Can be cut directly from host DNA / use of restriction enzymes.
[1]
RNA can be extracted / use of messenger RNA
and treated with reverse transcriptase
which turns RNA into DNA
i.e. Reverse transcriptase and a description of the process.
[2]
GCE BIOLOGY Specimen Assessment Materials 98
(d)
Reversion of virus to disease causing form
Bacteria / virus could be toxic to humans or insects
Virus / bacterium could transfer to another species
Accept ref. ethical reasons qualified e.g. Why change colour of leaves when
there is no nutritional value?
Accept ref. increase cost of plants putting financial burden on farmers
Accept other valid points e.g. unknown future side effects.
(not: playing God / genes escaping)
(e)
(i)
protein and nucleic acid / DNA / RNA
(ii)
Use of liposomes;
[Max. 2]
[1]
Transfer of non CF gene (into plasmid);
Coated in (spheres of) phospholipids / lipid (bilayer);
Breathed into lung via aerosol / inhaler.
(iii)
[3]
Gets into nucleus;
Insertion into genome / chromosome;
Transcription / eq. (in context);
Translation / eq. (in context).
[3]
(Total 15 marks)
GCE BIOLOGY Specimen Assessment Materials 99
6.
(a)
(b)
(c)
(i)
Fusarium
[1]
(ii)
banana plants genetically identical / clones;
same susceptibility / lack of resistance to Panama disease;
no / little mutation;
close planting enabled easy spread.
(Any 3)
[3]
natural selection;
fungicide is selective agent / selective pressure;
variation between individuals;
chance / random mutation;
some individuals have selective advantage / better change of surviving;
survival of resistants / death of non-resistants (not: survival of the fittest);
mutation / ability to survive pesticide passed on to offspring;
increased allele frequency.
(Any 7)
[7]
normally achieved with breeding programmes;
(using) reservoir of genes / alleles;
bananas are sterile / seedless / reproduce asexually;
so no easy way to incorporate new genes / alleles.
(Any 3)
[3]
(Total 14 marks)
GCE BIOLOGY Specimen Assessment Materials 100
7.
(a)
A
in plant tissue culture plants are grown from parts of a plant / cuttings /
suitable example
B
reference to term tissue culture / micropropagation
C
(explants) placed in sterile, (aerated) medium
D
cells divide (by mitosis)
E
to form callus
F
callus differentiates into plantlet
G
plantlets transplanted into (sterile) soil when big enough / eq. e.g. grown on
H
in animals a nucleus / DNA may be removed from diploid / somatic / udder /
body / undifferentiated cell
I
transferred to an exnucleated egg cell / egg cell with no nucleus
J
or an embryo split before differentiation/at early stage
K
the embryo allowed to develop in a surrogate (uterus)
L
reference to totipotent / stem cells / pre differentiation in either
M
advantages: maintain genetic stocks / gene library more quickly than seed
propagation / rapid increase in nos. / standardisation for transport / ref. to cost
qualified
N
disadvantages: in mammals unforeseen long term effects e.g. premature
ageing / gigantism
O
no variation / disease / entry of pathogens may be a problem
(Total 10 Marks)
GCE BIOLOGY Specimen Assessment Materials 101
(b)
Forestry / Fishing
A
Habitat destruction / comment on destruction balanced ecosystems
B
Leading to reduction in biodiversity / owtte
C
Qual of above e.g. loss of potentially important therapeutic plants / reduction
gene pool
D
Tree removal leads to soil erosion / dust bowls
E
Causing increase in sedimentation / deposits
F
Plant removal contributes to climate change / example / ref. to global
warming
G
Fall in CO2 reduction / raising CO2 levels / O2
H
Reduction of fish population to below sustainable levels / numbers cannot be
maintained - will be further decline
I
Curtailment of breeding due to fewer mature fish
J
So no regeneration
K
Quotas could reduce catches while maintaining industry
L
Managed areas / farms to supply commercial timber / fish / plant renewable
resources
M
Reduction fleet size / number of days fishing reduce number of fish taken
N
Exclusion zones / protected areas allow population to rebuild
O
Restricted mesh size to allow young fish to escape and breed.
(Total 10 Marks)
GCE BIOLOGY Specimen Assessment Materials 102
WELSH JOINT EDUCATION COMMITTEE
CYD-BWYLLGOR ADDYSG CYMRU
General Certificate of Education
Tystysgrif Addysg Gyffredinol
MARK SPECIFICATION GRID
GCE BIOLOGY
UNIT TEST
Year of Examination ____Specimen______
Page__1____of_____1__
Session: summer/winter
Unit _BY5_
Assessment Objective
Paper
Other requirements
Total
Mark
Question
Number
Target Totals
AS BY1, BY2
A2 BY4, BY5
Specification
Reference
AO1
AO2
AO3
33
30
33
45
4
5
70
80
Synoptic
Quality of
written
com'cn.
N/A
9
9
9
1
5.7
1
5
6
2
5.5
3
5
8
9
3
5.4
2
9
2
13
9
4
5.1
9
4
1
14
9
9
5
5.6
7
8
15
9
9
6
5.4/5.5
4
9
1
14
9
9
7
5.8 / 5.6
5
4
1
10
31
44
5
80
Raw Totals:
GCE Biology SAMs (2009-2010)/ED
30 July 2007
9