2023 AQA A-level BIOLOGY 7402/2 Paper 2
Question Paper & Mark scheme (Merged) June
2023 [VERIFIED]
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A-level
BIOLOGY
Paper 2
Friday 16 June 2023 Morning 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
For Examiner’s Use
Question Mark
1
2
3
4
5
6
7
8
9
10
TOTAL
• The marks for the questions are shown in brackets.
• The maximum mark for this paper is 91.
2
Answer all questions in the spaces provided.
0 1 . 1 A student used chromatography to separate the different photosynthetic pigments in a
chlorophyll solution. She had the following materials.
Chromatography paper
A ruler and pencil
Suitable glassware
A solvent (solvent A)
2 cm3
of the chlorophyll solution
Describe how she could use these materials to separate the photosynthetic
pigments by chromatography.
[4 marks]
0 1 . 2 Using solvent A, the student separated five pigments. She then repeated her method
using a different solvent, B. Using solvent B, she separated six pigments.
Explain the difference between these results.
[2 marks]
Do not write
outside the
box
6
*02*
IB/M/Jun23/7402/2
3
0 2 . 1 Glutamate is a neurotransmitter involved in the transmission of nerve impulses from pain
receptors to the brain. Ziconotide is a drug that can reduce severe, constant pain.
Ziconotide blocks the calcium ion channels at some of the synapses which use
glutamate.
The transmission of glutamate at synapses is similar to that of acetylcholine.
Explain how ziconotide reduces severe, constant pain.
[5 marks]
Ziconotide is a polypeptide and acts on synapses in the spinal cord. Scientists
investigated the effectiveness of ziconotide in reducing severe, constant pain.
Ziconotide was injected into each patient’s cerebrospinal fluid that bathes the brain
and spinal cord. Patients recorded the intensity of their pain using a statistically
valid scale.
0 2 . 2 Suggest two reasons why the patients had ziconotide injected into their
cerebrospinal fluid rather than taking a pill containing the drug.
[2 marks]
1
2
Question 2 continues on the next page
Turn over ►
*03*
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outside the
box
IB/M/Jun23/7402/2
4
0 2 . 3 Ziconotide was injected at 3 ng kg–1
h
–1
for 8 days into each patient. 1
ng = 1 × 10–9
g
Calculate the total mass in grams of ziconotide injected after 8 days into a patient
with a body mass of 82 kg
Show your working.
[2 marks]
Answer g
0 2 . 4 When the patients recorded the intensity of pain, suggest two reasons why it was
important to use a statistically valid scale.
[2 marks]
1
2
Do not write
outside the
box
11
*04*
IB/M/Jun23/7402/2
5
0 3Figure 1 shows part of a phosphorus cycle, including the mass of phosphorus in two
stores.
Figure 1
One teragram (Tg) is 1 × 1012
grams.
The supply of phosphorus to the soil is shown as a percentage of the total
phosphorus mass of each store.
0 3 . 1 Calculate in teragrams the difference in the supply of phosphorus to the soil from the
two stores shown in Figure 1.
Show your working.
[2 marks]
Answer Tg
Question 3 continues on the next page
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*05*
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outside the
box
IB/M/Jun23/7402/2
6
Water shortage can inhibit crop production. Scientists investigated the effect of the
mycorrhizal species Glomus intraradices on the growth of tomato plants under
conditions of water shortage and no water shortage.
• The scientists planted tomato seeds into a large number of pots containing
sterilised soil.
• They added a culture of G. intraradices to 50% of the pots and 50% were left
untreated.
• After the seeds had developed into seedlings (young plants), the seedlings from the
untreated and treated pots were planted into four separate large greenhouses
(glasshouses).
• A very limited supply of water (water shortage) was provided to two of the
greenhouses. A sufficient supply of water (no water shortage) was provided to the
other two greenhouses.
• After 60 days, the scientists determined the mean mass of tomatoes (kg m–2
)
from each greenhouse.
Greenhouse P – untreated seedlings with water shortage
Greenhouse Q – treated seedlings with water shortage
Greenhouse R – untreated seedlings with no water shortage
Greenhouse S – treated seedlings with no water shortage
Treated seedlings are plants grown with G. intr [Show Less]