PMT Please write clearly in block capitals. Centre number Candidate number Surname Forename(s) Candidate signature I declare this is my own work. H GCSE BIOLOGY Higher Tier Paper 2 H Friday 9 June 2023 Afternoon Time allowed: 1 hour 45 minutes Materials For Examiner’s Use For this paper you must have: • a ruler Question Mark • a scientific calculator. 1 Instructions 2 • Use black ink or black ball-point pen. 3 • Pencil should only be used for drawing. 4 • Fill in the boxes at the top of this page. 5 • Answer all questions in the spaces provided. • If you need extra space for your answer(s), use the lined pages at the end of 6 this book. Write the question number against your answer(s). 7 • Do all rough work in this book. Cross through any work you do not want 8 to be marked. • In all calculations, show clearly how you work out your answer. 9 TOTAL Information • The maximum mark for this paper is 100. • The marks for questions are shown in brackets. • You are expected to use a calculator where appropriate. • You are reminded of the need for good English and clear presentation in your answers. * jun2384612H01 * 8461/2H IB/M/Jun23/E21

PMT
Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
H
GCSE
BIOLOGY
Higher Tier Paper 2 H
Friday 9 June 2023 Afternoon Time allowed: 1 hour 45 minutes
Materials
For this paper you must have: For Examiner’s Use
• a ruler
Question Mark
• a scientific calculator.
1
Instructions 2
• Use black ink or black ball-point pen. 3
• Pencil should only be used for drawing.
4
• Fill in the boxes at the top of this page.
• Answer all questions in the spaces provided. 5
• If you need extra space for your answer(s), use the lined pages at the end of 6
this book. Write the question number against your answer(s). 7
• Do all rough work in this book. Cross through any work you do not want
8
to be marked.
• In all calculations, show clearly how you work out your answer. 9
TOTAL
Information
• The maximum mark for this paper is 100.
• The marks for questions are shown in brackets.
• You are expected to use a calculator where appropriate.
• You are reminded of the need for good English and clear presentation
in your answers.
* jun2384612H01 * 8461/2H
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PMT 2 Do not write outside the There are no questions printed on this page box DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED * 02 * IB/M/Jun23/8461/2H

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DO NOT WRITE ON THIS PAGE
ANSWER IN THE SPACES PROVIDED
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PMT 3 Do not write outside the Answer all questions in the spaces provided. box 0 1 Many different species can live together in the same habitat. 0 1 . 1 What name is given to all of the organisms living in the same habitat? [1 mark] Tick (  ) one box. A community A food chain A population An ecosystem Question 1 continues on the next page Turn over ► * 03 * IB/M/Jun23/8461/2H

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Answer all questions in the spaces provided. box
0 1 Many different species can live together in the same habitat.
0 1 . 1 What name is given to all of the organisms living in the same habitat?
[1 mark]
Tick (  ) one box.
A community
A food chain
A population
An ecosystem
Question 1 continues on the next page
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PMT 4 Do not write outside the box Figure 1 shows four species of bird from the same habitat in the UK. Figure 1 Brambling ( Fringilla montifringilla ) Bullfinch ( Pyrrhula pyrrhula ) Chaffinch ( Fringilla coelebs ) Goldfinch ( Carduelis carduelis ) * 04 * IB/M/Jun23/8461/2H

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Figure 1 shows four species of bird from the same habitat in the UK.
Figure 1
Brambling ( Fringilla montifringilla ) Bullfinch ( Pyrrhula pyrrhula )
Chaffinch ( Fringilla coelebs ) Goldfinch ( Carduelis carduelis )
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PMT 5 Do not write outside the 0 1 . 2 Which species of bird in Figure 1 do scientists think are most closely related? box [1 mark] Tick (  ) one box. Brambling and chaffinch Brambling and goldfinch Bullfinch and chaffinch Bullfinch and goldfinch 0 1 . 3 Scientists think the brambling and the bullfinch belong to different species. What evidence is used by scientists to classify the brambling and the bullfinch as different species? [1 mark] Tick (  ) one box. The brambling and the bullfinch are different sizes. The brambling and the bullfinch cannot breed together to give fertile offspring. The brambling and the bullfinch live in different parts of the habitat. The brambling eats mainly seeds and the bullfinch eats mainly insects. Question 1 continues on the next page Turn over ► * 05 * IB/M/Jun23/8461/2H

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0 1 . 2 Which species of bird in Figure 1 do scientists think are most closely related? box
[1 mark]
Tick (  ) one box.
Brambling and chaffinch
Brambling and goldfinch
Bullfinch and chaffinch
Bullfinch and goldfinch
0 1 . 3 Scientists think the brambling and the bullfinch belong to different species.
What evidence is used by scientists to classify the brambling and the bullfinch as
different species?
[1 mark]
Tick (  ) one box.
The brambling and the bullfinch are different sizes.
The brambling and the bullfinch cannot breed together to give fertile
offspring.
The brambling and the bullfinch live in different parts of the habitat.
The brambling eats mainly seeds and the bullfinch eats mainly insects.
Question 1 continues on the next page
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PMT 6 Do not write outside the Four other species of bird ( A , B , C and D ) live in a habitat in the UK. box Figure 2 shows how the numbers of each species of bird varied during one year. Figure 2 Use information from Figure 2 to answer Questions 01.4 to 01. 6 0 1 . 4 Describe what happens to the number of birds of species A during the year. [ 3 marks] * 06 * IB/M/Jun23/8461/2H

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Four other species of bird ( A , B , C and D ) live in a habitat in the UK. box
Figure 2 shows how the numbers of each species of bird varied during one year.
Figure 2
Use information from Figure 2 to answer Questions 01.4 to 01. 6
0 1 . 4 Describe what happens to the number of birds of species A during the year.
[ 3 marks]
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PMT 7 Do not write outside the 0 1 . 5 In June and July, a disease affected the populations of some of the species. box Which species had the lowest resistance to the disease? [1 mark] Tick (  ) one box. A B C D 0 1 . 6 One species migrates between the UK and other countries. Which species migrates between the UK and other countries? Give a reason for your answer. [1 mark] Species Reason 8 Turn over for the next question Turn over ► * 07 * IB/M/Jun23/8461/2H

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0 1 . 5 In June and July, a disease affected the populations of some of the species. box
Which species had the lowest resistance to the disease?
[1 mark]
Tick (  ) one box.
A B C D
0 1 . 6 One species migrates between the UK and other countries.
Which species migrates between the UK and other countries?
Give a reason for your answer.
[1 mark]
Species
Reason
8
Turn over for the next question
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PMT 8 Do not write outside the 0 2 A person’s eyes can focus on objects at different distances. box A person looks at a distant object. The person then looks at a near object. The person’s eyes make adjustments so that the near object forms a clear image. 0 2 . 1 Which term describes the adjustment of focus from the distant object to the near object? [1 mark] Tick (  ) one box. Accommodation Adaptation Hyperopia Myopia Figure 3 shows the eye. Figure 3 . * 08 * IB/M/Jun23/8461/2H

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0 2 A person’s eyes can focus on objects at different distances. box
A person looks at a distant object.
The person then looks at a near object.
The person’s eyes make adjustments so that the near object forms a clear image.
0 2 . 1 Which term describes the adjustment of focus from the distant object to the
near object?
[1 mark]
Tick (  ) one box.
Accommodation
Adaptation
Hyperopia
Myopia
Figure 3 shows the eye.
Figure 3
.
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PMT 9 Do not write outside the 0 2 . 2 Which structure in Figure 3 is where the image is focused ? box [1 mark] Tick (  ) one box. A B C D E 0 2 . 3 Which structure in Figure 3 is a muscle that contracts when focusing on a near object ? [1 mark] Tick (  ) one box. A B C D E 0 2 . 4 What happens to the shape of the lens when focusing on a near object? [1 mark] 0 2 . 5 The eyes can function in dimly-lit areas and in brightly-lit areas. The iris contains muscles. Describe how muscles in the iris help the person to see clearly when moving from a dimly-lit area to a brightly-lit area. [ 2 marks] Turn over ► * 09 * IB/M/Jun23/8461/2H

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9
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0 2 . 2 Which structure in Figure 3 is where the image is focused ? box
[1 mark]
Tick (  ) one box.
A B C D E
0 2 . 3 Which structure in Figure 3 is a muscle that contracts when focusing on a
near object ?
[1 mark]
Tick (  ) one box.
A B C D E
0 2 . 4 What happens to the shape of the lens when focusing on a near object?
[1 mark]
0 2 . 5 The eyes can function in dimly-lit areas and in brightly-lit areas.
The iris contains muscles.
Describe how muscles in the iris help the person to see clearly when moving from a
dimly-lit area to a brightly-lit area.
[ 2 marks]
Turn over ►
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PMT 10 Do not write outside the 0 2 . 6 It is important to be able to react quickly. box Many people think that drinking coffee decreases reaction time. Plan an investigation to test the effect of drinking coffee on reaction time. You should include: • the test for reaction time that you would use • how to make the investigation valid. [4 marks] 10 * 10 * IB/M/Jun23/8461/2H

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0 2 . 6 It is important to be able to react quickly. box
Many people think that drinking coffee decreases reaction time.
Plan an investigation to test the effect of drinking coffee on reaction time.
You should include:
• the test for reaction time that you would use
• how to make the investigation valid.
[4 marks]
10
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PMT 11 Do not write outside the Turn over for the next question box DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED Turn over ► * 11 * IB/M/Jun23/8461/2H

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ANSWER IN THE SPACES PROVIDED
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PMT 12 Do not write outside the 0 3 Reproduction can produce offspring which are: box • genetically different or • genetically identical . Farmers grow tomato plants in greenhouses. The tomatoes are sold in supermarkets. 0 3 . 1 Suggest one advantage of growing tomato plants that are genetically different. [1 mark] 0 3 . 2 Suggest one advantage of growing tomato plants that are genetically identical. [1 mark] 0 3 . 3 Scientists can grow genetically identical tomato plants using tissue culture. What is tissue culture? [1 mark] 0 3 . 4 Genetically identical tomato plants growing in the same garden do not all grow to the same height. Give one reason why. [1 mark] * 12 * IB/M/Jun23/8461/2H

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0 3 Reproduction can produce offspring which are: box
• genetically different
or
• genetically identical .
Farmers grow tomato plants in greenhouses.
The tomatoes are sold in supermarkets.
0 3 . 1 Suggest one advantage of growing tomato plants that are genetically different.
[1 mark]
0 3 . 2 Suggest one advantage of growing tomato plants that are genetically identical.
[1 mark]
0 3 . 3 Scientists can grow genetically identical tomato plants using tissue culture.
What is tissue culture?
[1 mark]
0 3 . 4 Genetically identical tomato plants growing in the same garden do not all grow to the
same height.
Give one reason why.
[1 mark]
* 12 *
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PMT 13 Do not write outside the The sex of dogs is determined by X and Y chromosomes in the same way as box in humans. 0 3 . 5 Complete the Punnett square diagram in Figure 4 to show the inheritance of sex in dogs. Use the symbols X and Y . [3 marks] Figure 4 Female Male 0 3 . 6 A female dog gave birth to six offspring. Why would you expect there to be three male offspring and three female offspring? Use your answer to Question 03.5 . [1 mark] Question 3 continues on the next page Turn over ► * 13 * IB/M/Jun23/8461/2H

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The sex of dogs is determined by X and Y chromosomes in the same way as box
in humans.
0 3 . 5 Complete the Punnett square diagram in Figure 4 to show the inheritance of sex
in dogs.
Use the symbols X and Y .
[3 marks]
Figure 4
Female
Male
0 3 . 6 A female dog gave birth to six offspring.
Why would you expect there to be three male offspring and three female offspring?
Use your answer to Question 03.5 .
[1 mark]
Question 3 continues on the next page
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PMT 14 Do not write outside the Farmers keep chickens for: box • meat production • egg production. Some varieties of chicken grow more quickly and are more suitable for meat production. Other varieties of chicken produce more eggs. A farmer keeps two varieties of chicken, A and B . The farmer investigated the growth rates and egg-production rates of both varieties. Figure 5 shows the results. Figure 5 0 3 . 7 Suggest two control variables the farmer should have used in this investigation. [2 marks] 1 2 * 14 * IB/M/Jun23/8461/2H

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14
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Farmers keep chickens for: box
• meat production
• egg production.
Some varieties of chicken grow more quickly and are more suitable for
meat production.
Other varieties of chicken produce more eggs.
A farmer keeps two varieties of chicken, A and B .
The farmer investigated the growth rates and egg-production rates of both varieties.
Figure 5 shows the results.
Figure 5
0 3 . 7 Suggest two control variables the farmer should have used in this investigation.
[2 marks]
1
2
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PMT 15 Do not write outside the 0 3 . 8 Figure 5 shows mean values from 500 chickens of each variety. box Give the reason the farmer used a large number of chickens. [ 1 mark] 0 3 . 9 The farmer wants to produce a new variety of chicken that is good for both meat production and egg production. Describe how selective breeding of chicken varieties A and B can produce the new variety of chicken. [4 marks] 15 Turn over for the next question Turn over ► * 15 * IB/M/Jun23/8461/2H

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15
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0 3 . 8 Figure 5 shows mean values from 500 chickens of each variety. box
Give the reason the farmer used a large number of chickens.
[ 1 mark]
0 3 . 9 The farmer wants to produce a new variety of chicken that is good for both meat
production and egg production.
Describe how selective breeding of chicken varieties A and B can produce the new
variety of chicken.
[4 marks]
15
Turn over for the next question
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PMT 16 Do not write outside the There are no questions printed on this page box DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED * 16 * IB/M/Jun23/8461/2H

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ANSWER IN THE SPACES PROVIDED
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PMT 17 Do not write outside the 0 4 Organic substances decay into simpler substances. box 0 4 . 1 The leaves fall off many trees in autumn. The dead leaves contain carbon compounds and nitrogen compounds. Describe how carbon and nitrogen in compounds in the leaves are recycled and used by living trees. You should include a description of: • how the leaves are broken down • how substances are taken in and used by the trees. [ 6 mark s ] Question 4 continues on the next page Turn over ► * 17 * IB/M/Jun23/8461/2H

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0 4 Organic substances decay into simpler substances. box
0 4 . 1 The leaves fall off many trees in autumn.
The dead leaves contain carbon compounds and nitrogen compounds.
Describe how carbon and nitrogen in compounds in the leaves are recycled and used
by living trees.
You should include a description of:
• how the leaves are broken down
• how substances are taken in and used by the trees.
[ 6 mark s ]
Question 4 continues on the next page
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PMT 18 Do not write outside the Students investigated the effect of temperature on the decay of milk. box This is the method used. 1. Place 25 cm 3 of fresh milk into each of three beakers. 2. Keep one beaker of milk at 5 ° C. 3. Keep one beaker of milk at 15 ° C. 4. Keep one beaker of milk at 25 ° C. 5. Record the pH of the milk in each beaker every day for 4 days. Table 1 shows the results. Table 1 pH of milk Time in days 5 C 15 C 25 C 0 6.8 6.8 6.8 1 6.5 6.1 5.3 2 6.2 5.5 4.9 3 5.9 5.1 4.8 4 5.6 4.8 4.8 0 4 . 2 Suggest one improvement the students could have made to the method. [1 mark] * 18 * IB/M/Jun23/8461/2H

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Students investigated the effect of temperature on the decay of milk. box
This is the method used.
1. Place 25 cm 3 of fresh milk into each of three beakers.
2. Keep one beaker of milk at 5 ° C.
3. Keep one beaker of milk at 15 ° C.
4. Keep one beaker of milk at 25 ° C.
5. Record the pH of the milk in each beaker every day for 4 days.
Table 1 shows the results.
Table 1
pH of milk
Time in
days
5 C 15 C 25 C
0 6.8 6.8 6.8
1 6.5 6.1 5.3
2 6.2 5.5 4.9
3 5.9 5.1 4.8
4 5.6 4.8 4.8
0 4 . 2 Suggest one improvement the students could have made to the method.
[1 mark]
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PMT 19 Do not write outside the Figure 6 shows the results at 5 ° C and at 15 ° C. box Figure 6 0 4 . 3 Complete Figure 6 . You should: • plot the data for 25 ° C from Table 1 • draw a line of best fit. [3 marks] Question 4 continues on the next page Turn over ► * 19 * IB/M/Jun23/8461/2H

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Figure 6 shows the results at 5 ° C and at 15 ° C. box
Figure 6
0 4 . 3 Complete Figure 6 .
You should:
• plot the data for 25 ° C from Table 1
• draw a line of best fit.
[3 marks]
Question 4 continues on the next page
Turn over ►
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PMT 20 Do not write outside the Figure 7 shows the results for 5 ° C and at 15 ° C again. box Figure 7 * 20 * IB/M/Jun23/8461/2H

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Figure 7 shows the results for 5 ° C and at 15 ° C again. box
Figure 7
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PMT 21 Do not write outside the 0 4 . 4 The rate of pH change increases with an increase in temperature. box The rate of pH change at 5 ° C is 0.3 pH units per day. Calculate how many times faster the rate of pH change is at 15 ° C than the rate of pH change at 5 ° C, at day 2 . You should draw a tangent on Figure 7 . [4 marks] Rate at 15 ° C is times faster. 0 4 . 5 Milk contains lipids. The lipids are broken down when the milk decays. Explain why the pH changes more quickly when the temperature is higher. [3 marks] 17 Turn over for the next question Turn over ► * 21 * IB/M/Jun23/8461/2H

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0 4 . 4 The rate of pH change increases with an increase in temperature. box
The rate of pH change at 5 ° C is 0.3 pH units per day.
Calculate how many times faster the rate of pH change is at 15 ° C than the rate of pH
change at 5 ° C, at day 2 .
You should draw a tangent on Figure 7 .
[4 marks]
Rate at 15 ° C is times faster.
0 4 . 5 Milk contains lipids.
The lipids are broken down when the milk decays.
Explain why the pH changes more quickly when the temperature is higher.
[3 marks]
17
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PMT 22 Do not write outside the 0 5 Homeostasis is the regulation of the body’s internal conditions. box Many internal conditions are controlled by hormones. Homeostasis works by negative feedback control. 0 5 . 1 Figure 8 shows how the concentration of substance Q in the blood is controlled by negative feedback. Figure 8 Explain how the concentration of substance Q in the blood is controlled by negative feedback. Use information from Figure 8 . [3 marks] * 22 * IB/M/Jun23/8461/2H

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0 5 Homeostasis is the regulation of the body’s internal conditions. box
Many internal conditions are controlled by hormones.
Homeostasis works by negative feedback control.
0 5 . 1 Figure 8 shows how the concentration of substance Q in the blood is controlled by
negative feedback.
Figure 8
Explain how the concentration of substance Q in the blood is controlled by
negative feedback.
Use information from Figure 8 .
[3 marks]
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PMT 23 Do not write outside the 0 5 . 2 Thyroxine is a hormone produced by the thyroid gland. box A decrease in body temperature causes an increase in thyroxine production. Explain how the production of thyroxine causes an increase in body temperature. [2 marks] Question 5 continues on the next page Turn over ► * 23 * IB/M/Jun23/8461/2H

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0 5 . 2 Thyroxine is a hormone produced by the thyroid gland. box
A decrease in body temperature causes an increase in thyroxine production.
Explain how the production of thyroxine causes an increase in body temperature.
[2 marks]
Question 5 continues on the next page
Turn over ►
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PMT 24 Do not write outside the 0 5 . 3 ADH is a hormone made by the pituitary gland. box ADH controls how much water is reabsorbed from the kidney tubules. Table 2 shows effects of ADH. Table 2 Concentration of Concentration of ADH Rate of urine dissolved substances in the blood in production in in urine in arbitrary nanograms/dm 3 cm 3 /minute units 0.0 50 20.0 1.25 700 8.8 2.50 980 3.9 3.75 1110 1.8 5.00 1170 0.9 The concentration of ADH in a man’s blood was 3.75 nanograms/dm 3 . The concentration of ADH in his blood decreased to 1.25 nanograms/dm 3 . Explain how the decrease in the concentration of ADH would cause the changes to the urine shown in Table 2 . [4 marks] 9 * 24 * IB/M/Jun23/8461/2H

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0 5 . 3 ADH is a hormone made by the pituitary gland. box
ADH controls how much water is reabsorbed from the kidney tubules.
Table 2 shows effects of ADH.
Table 2
Concentration of
Concentration of ADH Rate of urine
dissolved substances
in the blood in production in
in urine in arbitrary
nanograms/dm 3 cm 3 /minute
units
0.0 50 20.0
1.25 700 8.8
2.50 980 3.9
3.75 1110 1.8
5.00 1170 0.9
The concentration of ADH in a man’s blood was 3.75 nanograms/dm 3 .
The concentration of ADH in his blood decreased to 1.25 nanograms/dm 3 .
Explain how the decrease in the concentration of ADH would cause the changes to
the urine shown in Table 2 .
[4 marks]
9
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PMT 25 Do not write outside the Turn over for the next question box DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED Turn over ► * 25 * IB/M/Jun23/8461/2H

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ANSWER IN THE SPACES PROVIDED
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PMT 26 Do not write outside the 0 6 This question is about the effects of deforestation and agriculture. box The processes of photosynthesis and respiration affect the carbon dioxide concentration in the air. Figure 9 shows the changes in the carbon dioxide concentration in the air in a tropical rainforest during one day. The data are mean daily values over a whole year. Figure 9 0 6 . 1 Explain what causes the changes in the carbon dioxide concentration in the air: • from 0 to 6 hours • from 8 to 12 hours. Use information from Figure 9 . [4 marks] 0 to 6 hours 8 to 12 hours * 26 * IB/M/Jun23/8461/2H

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0 6 This question is about the effects of deforestation and agriculture. box
The processes of photosynthesis and respiration affect the carbon dioxide
concentration in the air.
Figure 9 shows the changes in the carbon dioxide concentration in the air in a tropical
rainforest during one day.
The data are mean daily values over a whole year.
Figure 9
0 6 . 1 Explain what causes the changes in the carbon dioxide concentration in the air:
• from 0 to 6 hours
• from 8 to 12 hours.
Use information from Figure 9 .
[4 marks]
0 to 6 hours
8 to 12 hours
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PMT 27 Do not write outside the 0 6 . 2 An area of rainforest is cut down and replaced with a field of maize plants. box Only one crop of maize is grown each year. Figure 10 shows the changes in the carbon dioxide concentration in the air in the field of maize during one day. The data are mean daily values over the 6-month growing period. Figure 10 The maize grows for only 6 months of the year. Explain why replacing rainforest with maize will increase the carbon dioxide concentration in the air after one year. Use information from Figure 9 and Figure 10 . [ 2 marks] Question 6 continues on the next page Turn over ► * 27 * IB/M/Jun23/8461/2H

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0 6 . 2 An area of rainforest is cut down and replaced with a field of maize plants. box
Only one crop of maize is grown each year.
Figure 10 shows the changes in the carbon dioxide concentration in the air in the field
of maize during one day.
The data are mean daily values over the 6-month growing period.
Figure 10
The maize grows for only 6 months of the year.
Explain why replacing rainforest with maize will increase the carbon dioxide
concentration in the air after one year.
Use information from Figure 9 and Figure 10 .
[ 2 marks]
Question 6 continues on the next page
Turn over ►
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PMT 28 Do not write outside the A tropical rainforest can contain over 1000 different tree species. box Large areas of tropical rainforest have been cut down during the last 100 years so crops can be grown. Scientists studied the regeneration of different areas of tropical rainforest. The scientists: • investigated areas of rainforest that had been cut down at different times during the previous 100 years • recorded the number of tree species that re-grew in each area • compared each area with a control area next to it. The control areas were undisturbed rainforest which had never been cut down. Figure 11 shows the scientists’ results. Figure 11 * 28 * IB/M/Jun23/8461/2H

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28
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A tropical rainforest can contain over 1000 different tree species. box
Large areas of tropical rainforest have been cut down during the last 100 years so
crops can be grown.
Scientists studied the regeneration of different areas of tropical rainforest.
The scientists:
• investigated areas of rainforest that had been cut down at different times during the
previous 100 years
• recorded the number of tree species that re-grew in each area
• compared each area with a control area next to it. The control areas were
undisturbed rainforest which had never been cut down.
Figure 11 shows the scientists’ results.
Figure 11
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PMT 29 Do not write outside the 0 6 . 3 The values plotted in Figure 11 are percentages of the results for the control areas. box Explain why the scientists presented their results as percentages . [2 marks] During the 100 years, the biodiversity of trees in the regenerating rainforest increases. 0 6 . 4 Give one other conclusion you can make from Figure 11 . [ 1 mark] 0 6 . 5 Give two reasons why an increase in the diversity of trees in the rainforest leads to an increase in animal diversity. [2 marks] 1 2 11 Turn over for the next question Turn over ► * 29 * IB/M/Jun23/8461/2H

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0 6 . 3 The values plotted in Figure 11 are percentages of the results for the control areas. box
Explain why the scientists presented their results as percentages .
[2 marks]
During the 100 years, the biodiversity of trees in the regenerating rainforest increases.
0 6 . 4 Give one other conclusion you can make from Figure 11 .
[ 1 mark]
0 6 . 5 Give two reasons why an increase in the diversity of trees in the rainforest leads to an
increase in animal diversity.
[2 marks]
1
2
11
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PMT 30 Do not write outside the 0 7 Hormones are important for regulating the menstrual cycle. box During the menstrual cycle, eggs mature inside follicles in the ovaries. A 27-year-old woman was infertile. A doctor tested a sample of the woman’s blood. The test did not detect any follicle stimulating hormone (FSH) in the woman’s blood. The doctor gave the woman daily injections of FSH for 7 days. The doctor measured: • the concentration of FSH in the woman’s blood • the concentration of oestrogen in the woman’s blood • the volumes of developing follicles in the ovaries. Figure 12 shows the results. Figure 12 * 30 * IB/M/Jun23/8461/2H

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0 7 Hormones are important for regulating the menstrual cycle. box
During the menstrual cycle, eggs mature inside follicles in the ovaries.
A 27-year-old woman was infertile.
A doctor tested a sample of the woman’s blood.
The test did not detect any follicle stimulating hormone (FSH) in the woman’s blood.
The doctor gave the woman daily injections of FSH for 7 days.
The doctor measured:
• the concentration of FSH in the woman’s blood
• the concentration of oestrogen in the woman’s blood
• the volumes of developing follicles in the ovaries.
Figure 12 shows the results.
Figure 12
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PMT 31 Do not write outside the 0 7 . 1 Give evidence from Figure 12 that the follicles in the ovaries release oestrogen . box [1 mark] 0 7 . 2 Injection of FSH caused the development of a number of follicles. The mean diameter of the follicles on day 11 was 22 millimetres. Calculate the number of follicles in the woman’s ovaries on day 11. Assume each follicle is a sphere. 4 π Volume of a sphere = r 3 3 r = radius π = 3.14 Give your answer to the nearest whole number . [5 marks ] Number of follicles (to the nearest whole number) = Question 7 continues on the next page Turn over ► * 31 * IB/M/Jun23/8461/2H

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0 7 . 1 Give evidence from Figure 12 that the follicles in the ovaries release oestrogen . box
[1 mark]
0 7 . 2 Injection of FSH caused the development of a number of follicles.
The mean diameter of the follicles on day 11 was 22 millimetres.
Calculate the number of follicles in the woman’s ovaries on day 11.
Assume each follicle is a sphere.
4
Volume of a sphere = π r 3
3
r = radius
π = 3.14
Give your answer to the nearest whole number .
[5 marks ]
Number of follicles (to the nearest whole number) =
Question 7 continues on the next page
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PMT 32 Do not write outside the 0 7 . 3 Before treatment with FSH, the woman had underdeveloped breasts. box Explain why the lack of FSH in the woman’s blood caused underdeveloped breasts . [2 marks] 0 7 . 4 Usually males and females both produce FSH. The woman had inherited a faulty gene for FSH production from each of her parents. The woman’s parents both produce FSH. Show how the woman’s parents could have a child that does not produce FSH. You should: • draw a Punnett square diagram • identify the phenotype of each offspring genotype • use the symbols below: H = allele for making FSH h = allele for not making FSH [3 marks] * 32 * IB/M/Jun23/8461/2H

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0 7 . 3 Before treatment with FSH, the woman had underdeveloped breasts. box
Explain why the lack of FSH in the woman’s blood caused underdeveloped breasts .
[2 marks]
0 7 . 4 Usually males and females both produce FSH.
The woman had inherited a faulty gene for FSH production from each of her parents.
The woman’s parents both produce FSH.
Show how the woman’s parents could have a child that does not produce FSH.
You should:
• draw a Punnett square diagram
• identify the phenotype of each offspring genotype
• use the symbols below:
H = allele for making FSH
h = allele for not making FSH
[3 marks]
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PMT 33 Do not write outside the 0 7 . 5 The woman continues to have injections of FSH. box The woman has a child with a man who is heterozygous for the FSH gene. Explain why the probability that the child will be able to produce FSH is 0.5. [3 marks] 14 Turn over for the next question Turn over ► * 33 * IB/M/Jun23/8461/2H

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0 7 . 5 The woman continues to have injections of FSH. box
The woman has a child with a man who is heterozygous for the FSH gene.
Explain why the probability that the child will be able to produce FSH is 0.5.
[3 marks]
14
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PMT 34 Do not write outside the 0 8 Figure 13 shows six stages in the process of meiosis. box Figure 13 0 8 . 1 In Figure 13 , A is the first stage and F is the final stage. Stages B to E are not in the correct order. Give the correct order of stages A to F . [1 mark] A → → → → → F * 34 * IB/M/Jun23/8461/2H

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0 8 Figure 13 shows six stages in the process of meiosis. box
Figure 13
0 8 . 1 In Figure 13 , A is the first stage and F is the final stage.
Stages B to E are not in the correct order.
Give the correct order of stages A to F .
[1 mark]
A → → → → → F
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PMT 35 Do not write outside the At the end of meiosis the number of chromosomes is different from the number of box chromosomes at the start of meiosis. 0 8 . 2 Give the number of chromosomes in one cell in Figure 13 : • at the start of meiosis • at the end of meiosis. [2 marks] Start End 0 8 . 3 Explain why the change in the number of chromosomes is important. [3 marks] 0 8 . 4 Meiosis produces cells that are genetically different. Describe how meiosis produces cells that are genetically different. [2 marks] Question 8 continues on the next page Turn over ► * 35 * IB/M/Jun23/8461/2H

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At the end of meiosis the number of chromosomes is different from the number of box
chromosomes at the start of meiosis.
0 8 . 2 Give the number of chromosomes in one cell in Figure 13 :
• at the start of meiosis
• at the end of meiosis.
[2 marks]
Start
End
0 8 . 3 Explain why the change in the number of chromosomes is important.
[3 marks]
0 8 . 4 Meiosis produces cells that are genetically different.
Describe how meiosis produces cells that are genetically different.
[2 marks]
Question 8 continues on the next page
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PMT 36 Do not write outside the Chromosomes contain DNA. box Figure 14 shows part of a DNA molecule. Figure 14 0 8 . 5 What type of substances are labelled A , C , G and T in Figure 14 ? [1 mark] 0 8 . 6 DNA is made of nucleotides. How many nucleotides are shown in Figure 14 ? [1 mark] 10 * 36 * IB/M/Jun23/8461/2H

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Chromosomes contain DNA. box
Figure 14 shows part of a DNA molecule.
Figure 14
0 8 . 5 What type of substances are labelled A , C , G and T in Figure 14 ?
[1 mark]
0 8 . 6 DNA is made of nucleotides.
How many nucleotides are shown in Figure 14 ?
[1 mark]
10
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PMT 37 Do not write outside the 0 9 A wide variety of species exists on Earth. box Most scientists accept Darwin’s theory of evolution by natural selection as the explanation for this variety of species. Explain how our understanding of evolution has developed due to: • fossil evidence • increased understanding of the mechanisms of genetics. [ 6 marks] 6 END OF QUESTIONS * 37 * IB/M/Jun23/8461/2H

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0 9 A wide variety of species exists on Earth. box
Most scientists accept Darwin’s theory of evolution by natural selection as the
explanation for this variety of species.
Explain how our understanding of evolution has developed due to:
• fossil evidence
• increased understanding of the mechanisms of genetics.
[ 6 marks]
6
END OF QUESTIONS
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PMT 38 Do not write outside the There are no questions printed on this page box DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED * 38 * IB/M/Jun23/8461/2H

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There are no questions printed on this page box
DO NOT WRITE ON THIS PAGE
ANSWER IN THE SPACES PROVIDED
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PMT 39 Do not write outside the box Question Additional page, if required. number Write the question numbers in the left-hand margin. * 39 * IB/M/Jun23/8461/2H

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39
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Question Additional page, if required. box
number Write the question numbers in the left-hand margin.
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PMT 40 Do not write outside the box Question Additional page, if required. number Write the question numbers in the left-hand margin. Copyright information For confidentiality purposes, all acknowledgements of third-party copyright material are published in a separate booklet. This booklet is published after each live examination series and is available for free download from www.aqa.org.uk. Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright-holders may have been unsuccessful and AQA will be happy to rectify any omissions of acknowledgements. If you have any queries please contact the Copyright Team. Copyright © 2023 AQA and its licensors. All rights reserved. * 236g8461/2H * * 40 * IB/M/Jun23/8461/2H

PMT
40
Do not write
outside the
box
Question Additional page, if required.
number Write the question numbers in the left-hand margin.
Copyright information
For confidentiality purposes, all acknowledgements of third-party copyright material are published in a separate booklet. This booklet
is published after each live examination series and is available for free download from www.aqa.org.uk.
Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright-holders may have
been unsuccessful and AQA will be happy to rectify any omissions of acknowledgements. If you have any queries please contact the
Copyright Team.
Copyright © 2023 AQA and its licensors. All rights reserved.
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June 2023 QP