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AQA A LEVEL ( 7402 /1) BIOLOGY PAPER 1 QUESTION PAPER+ MARK
SCHEME JUNE 2024
A-level
BIOLOGY
Paper 1
Wednesday 5 June 2024 Afternoon Time allowed: 2 hours
Materials
For this paper you must have:
a ruler with millimetre measurements
a scientific calculator.
Instructions
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.
Information
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
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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Do not write
outside the
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
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
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DO NOT WRITE ON THIS PAGE
ANSWER IN THE SPACES PROVIDED
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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]
A
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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Do not write
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
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
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Do not write
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 =
0.98 (P < 0.05)
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
UUU CGG GCG
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 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
PPO
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
- Cut a 1 cm cube of apple tissue from variety D.
- Put the cube on a plate and leave the plate at 30 °C
- Measure the time for the brown pigment to appear.
- Repeat steps 1 to 3 two more times.
- Repeat steps 1 to 4 with apple tissue from variety E.
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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