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AQA A LEVEL (7402/1) BIOLOGY PAPER 1 QUESTION PAPER+ MARK SCHEME JUNE 2024
Typology: Exams
1 / 55
Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signat ure
I declare this is my own work.
For this paper you must have:
a ruler with millimetre measurements
a scientific calculator.
Use black ink or black ball-point pen.
Fill in the boxes at the top of this page.
Answer all questions.
You must answer the questions in the spaces provided. Do not write
outside the box around each page or on blank pages.
If you need extra space for your answer(s), use the lined pages at the end of
this book. Write the question number against your answer(s).
Show all your working.
Do all rough work in this book. Cross through any work you do not
want to be marked.
The marks for the questions are shown in brackets.
The maximum mark for this paper is 91.
For Examiner’s Use
Question Mark
1 2 3 4 5 6 7 8 9
10
TOTAL
Do not write
outside the
box Answer all questions in the spaces provided.
Figure 1 shows the structure of a fatty acid molecule and the structure of a glycerol
molecule.
Figure 1
On Figure 1 , draw a circle around the part of the fatty acid molecule and the part of
the glycerol molecule that is removed to form a bond in a triglyceride molecule.
Name the bond formed between a fatty acid and glycerol in a triglyceride molecule.
Name the reaction involved in forming a bond between a fatty acid and glycerol in a
triglyceride molecule.
[3 marks]
Bond
Reaction
Do not write
outside the
box
Table 1 shows information about three fatty acids.
Table 1
. 2 Name the fatty acid shown in Table 1 that is a saturated fatty acid.
[1 mark]
The melting point is the temperature at which a solid changes state to be a liquid.
Use Table 1 to describe the relationship between fatty acid structure and fatty acid
melting point.
[1 mark]
Question 1 continues on the next page
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box 0 1
The ratio of saturated to unsaturated fatty acids in a cell-surface membrane
determines the extent of the membrane’s fluidity.
Scientists provided a cell culture of mouse phagocytes with liquid broth rich in
unsaturated fatty acids.
The scientists observed:
an increase in the proportion of phospholipids in the phagocytes containing
unsaturated fatty acids
more phagocytosis.
Suggest and explain why there was more phagocytosis.
[3 marks]
Do not write
outside the
box 0 2
Describe the processes of facilitated diffusion and active transport.
[3 marks]
Facilitated diffusion
Active transport
. 2 What are microvilli?
[1 mark]
Question 2 continues on the next page
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outside the
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Vitamin A is a fat-soluble substance.
Micelles are involved in the process of vitamin A absorption.
Describe the process of vitamin A absorption into cells lining the ileum.
[3 marks]
Do not write
outside the
box
Turn over for the next question
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. 1 Describe how we breathe in.
[3 marks]
A scientist prepared alveolar tissue to view using an optical microscope. The scientist
cut very thin slices of the alveolar tissue.
Explain why the scientist used very thin slices of alveolar tissue with the
optical microscope.
[2 marks]
Do not write
outside the
box 0 3
Figure 2 is an image of the lung tissue observed using an optical microscope.
Figure 2
Identify the tube labelled A.
[1 mark]
The scientist used a ruler to measure the diameter of some of the alveoli.
Table 2 shows the scientist’s results.
Table 2
Alveolus diameter / mm
Alveolus diameter / mm 4 2 5 1 2 3 5 2
. 4 The magnification of the image in Figure 2 is × 40
Use this information and Table 2 to calculate the mean diameter, in μm, of the alveoli.
Show your working.
[2 marks]
Answer μm
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outside the
box 0 3
Give the uncertainty associated with taking a measurement using a ruler with
1 mm graduations.
Calculate the percentage error for a measurement using the ruler of 4 mm
[2 marks]
Uncertainty ± mm
Percentage error
Do not write
outside the
box 0 4
Molasses is a solution obtained from sugar beet plants. The sugars present in
molasses are sucrose, glucose and fructose.
Give the number of different types of monosaccharides present in molasses.
[1 mark]
A student used the biochemical test for reducing sugars on a clear sample of
molasses.
Describe the biochemical test for a reducing sugar.
Explain the result expected from the test on the sample of molasses.
[3 marks]
Description of biochemical test
Explanation of expected result
. 3 ‘Free sugar’ is the sugar in food and drinks released when food is crushed or when
sugar is added to food at home or by manufacturers.
Scientists recommend that no more than 5% of the energy consumed per day should
come from ‘free sugar’.
The mean daily energy requirement for a 10 - year-old child is 8100 kJ
The ‘free sugar ’ in one tablespoon of molasses contains 250 kJ of energy.
Calculate the number of tablespoons of molasses required for a 10 - year-old child to
reach the recommendation for energy consumed in ‘free sugar’ per day.
[1 mark]
Number of tablespoons per day
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box 0 4
A scientist used the apparatus in Figure 3 to investigate osmosis.
Figure 3
Use your understanding of osmosis to explain why the air pressure in the
tube increased.
[3 marks]
Do not write
outside the
box 0 4
The scientist repeated the investigation, but made one change to the molasses. The
scientist did not change the volume of molasses at the start of the investigation.
The scientist observed that the air pressure inside the tube increased by 160 kPa
compared with 800 kPa in the first investigation.
Suggest the change the scientist made to the molasses to cause this smaller increase
in air pressure.
Use the air pressure figures in a calculation to support your answer.
[2 marks]
Suggested change
Turn over for the next question
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outside the
box 0 5
Describe the appearance and behaviour of chromosomes during prophase and during
anaphase of mitosis.
[4 marks]
Prophase
Anaphase
A scientist used an optical microscope to determine the mitotic index in cells at
different distances from the tip of onion roots.
Figure 4 shows the results.
Figure 4
Complete the word equation used to determine each mitotic index in Figure 4.
[1 mark]
Mitotic Index =
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outside the
box 0 5
The scientist used data from Figure 4 to calculate a correlation coefficient (r). The
scientist then used a statistical test to determine the probability (P) associated with the
value of r.
r =
What can you conclude from this result?
[2 marks]
What can you conclude about the effect that distance from the root tip has on the
proportion of cells in different stages of the cell cycle?
Use information in Figure 4.
[3 marks]
Turn over for the next question
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outside the
. Give three structural differences between an mRNA molecule and a tRNA molecule.
[3 marks]
mRNA tRNA
. Table 3 shows mRNA codons and the amino acid coded by each codon.
Table 3
Figure 5 shows the mRNA base sequence produced when part of a gene coding for
an enzyme is transcribed.
Figure 5
Use Table 3 to give the amino acids coded by the mRNA base sequence in Figure 5.
[1 mark]
box
Do not write
outside the
box 0 6
A mutation occurred in the part of the gene transcribed in Question 06..
Figure 6 shows the mRNA base sequence produced when the identical part in the
mutated gene is transcribed.
Figure 6
The amino acids coded by this mRNA base sequence form part of the enzyme’s
active site.
Use all the information in this question to:
name the type of mutation that occurred to produce the mutated gene
give the change in DNA caused by this mutation
explain the effect this mutation will have on the function of the enzyme.
[4 marks]
Type of mutation
Change in DNA
Explanation of effect on function of enzyme
Turn over for the next question
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Do not write
outside the
box 0 7
A student investigated the activity of the enzyme polyphenol oxidase (PPO) in
apple tissue.
When apple tissue is exposed to air, PPO catalyses a reaction between colourless
phenol compounds in apple tissue and oxygen.
Figure 7 shows the reaction.
Figure 7
phenol compounds + oxygen → brown pigment
The student measured the time taken for the brown pigment to appear in two apple
varieties ( D and E ).
Method
The student obtained the results shown below, but did not record the data in a
results table.
Variety D = 15 min 50 s, 18 min, 14 min 30 s
Variety E = 6 min 30 s, 8 min, 7 min
In the box labelled Figure 8 , design a suitable results table.
Enter the student’s results into the table.
Calculate the mean results and include these in the table.
Use 1 decimal place for both mean results.
[3 marks]
Do not write
outside the
box
Figure 8
. 2 Suggest and explain why the results for variety D are different from the results
for variety E.
[2 marks]
Question 7 continues on the next page
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box 0 7
The student repeated the investigation but made one change to the method used to
prepare the apple tissue.
The student then observed shorter times for the brown pigment to appear in both
apple varieties.
Suggest the change the student made to the method of preparing the apple tissue.
Explain why the brown pigment appeared in a shorter time.
Do not suggest using a different volume or mass of apple.
[3 marks]
Change to method
Explanation
. The student wants to change the procedure to obtain a measure of PPO activity either
in terms of how much substrate is used or how much product is produced.
Which change in procedure will provide a successful measure of PPO activity for
the student?
Tick () one box.
[1 mark]
Measure the increase in oxygen concentration in the air around the
cube of apple tissue on a plate.
Measure the intensity of brown colour by comparing apple tissue with
a colour chart showing a range of apple tissues of known pigment
concentration.
Measure the intensity of colour produced from brown apple tissue in
a biuret test.
Measure the percentage of light transmitted through a cube of brown
apple tissue using a colorimeter.
Do not write
outside the
box 0 8
Give two structural features of an aorta wall and explain how they are related to the
function of an aorta.
[2 marks]
Question 8 continues on the next page
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. 2 Small tears may occur in the layers of tissue in an aorta wall. These tears weaken the
wall without bursting the aorta.
Scientists:
measured the aorta diameter ( d ) in a large population of people over 60 years of
age
calculated the risk of an aorta wall developing a tear.
Table 4 shows their results.
Table 4
Aorta diameter d / cm
Number of people in
the population
Risk of an aorta wall
developing a tear
d ≤ 3.5 2765 0.06
3.5 < d ≤ 4.0 630 0.33
4.0 < d ≤ 4.5 98 4.64
d > 4.5 7 380.00
Blood may push through the tears in the aorta wall. This produces a balloon-like
swelling called an aneurysm and increases the aorta diameter. Aneurysms can cause
the aorta to burst.
Using all the information, what can you conclude about aorta diameter and the risk of
developing an aneurysm?
box
[3 marks]
Do not write
outside the
. A scientist investigated changes in a diseased heart and changes in a healthy heart
during cardiac cycles.
For each heart, the scientist obtained a value for:
the mean blood volume in a full ventricle just before the ventricle contracts ( BVB )
the mean ejection fraction ( EF ).
The EF is the proportion of blood pumped out of a full ventricle in one heartbeat.
The EF is calculated using this formula:
Blood volume pumped out of a full ventricle in one heartbeat (stroke volume)
box
Table 5 shows the scientist’s results.
Table 5
Diseased heart Healthy heart
Mean BVB / cm
3
Mean EF 0.45 0.58
Using Table 5 , a student calculated that the percentage change in the stroke volume
of the diseased heart compared with the stroke volume of a healthy heart is – 30%.
The student’s answer is wrong because the final step of the calculation was
performed incorrectly.
Using the equation and Table 5 , calculate the correct percentage change in the stroke
volume of the diseased heart compared with the stroke volume of the healthy heart.
Identify the mathematical error in the final step of the student’s calculation.
[3 marks]
Correct answer %
Mathematical error
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Courtship behaviour in the frog species, Xenopus laevis , involves male frogs
calling to:
attract sexually active females – these are advertisement calls
start and continue mating – these are mating calls
signal when a male is not sexually active – these are rasping calls.
Scientists investigated frog courtship behaviour by feeding a population of sexually
active male frogs a diet containing the hormone EE2. The scientists also fed a
separate control population of sexually active male frogs a diet without EE2.
They determined the percentage of males making advertisement calls or rasping calls
in each population.
Table 6 shows their results.
Table 6
box
Population
Percentage of males making:
Advertisement calls Rasping calls
Males fed EE2 94.0 4.0
Males not fed EE2 (control) 97.0 0.5
There were 800 males in the control population.
Each male made one type of call.
Use this information and Table 6 to calculate the number of males making mating
calls in the control population.
[1 mark]
Answer males