2025 AQA AS BIOLOGY Paper 1 Worked Exam Solutions (MARKING SCHEME
ATTACHED) Monday 12 May 2025 [VERIFIED]
Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
AS
BIOLOGY
Paper 1
Monday 12 May 2025 Morning Time allowed: 1 hour 30 minutes
Materials For Examiner’s Use
For this paper you must have:
Question Mark
a ruler with millimetre measurements
a scientific calculator. 1
2
Instructions
3
Use black ink or black ball-point pen.
Fill in the boxes at the top of this page. 4
Answer all questions. 5
You must answer the questions in the spaces provided. Do not write 6
outside the box around each page or on blank pages.
7
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). 8
Show all your working. 9
Do all rough work in this book. Cross through any work you do not want to be marked.
TOTAL
Information
The marks for the questions are shown in brackets.
The maximum mark for this paper is 75.
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7 4 0 1 /1
IB/M/Jun25/G4002/V5
, 2
Do not write
outside the
Answer all questions in the spaces provided. box
0 1 . 1 Figure 1 shows the structure of the amino acid alanine.
Figure 1
Name the NH2 and COOH groups in the amino acid. [1 mark]
NH2
COOH
Figure 2 shows the molecule formed from alanine and another amino acid.
Figure 2
0 1 . 2 Name the type of bond and the type of molecule formed when the two amino acids in
Figure 2 are joined.
[2 marks]
Type of bond
Type of molecule
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, 3
Do not write
outside the
0 1 . 3 Table 1 shows the R groups of six different amino acids. box
Table 1
Amino acid R group Amino acid R group
Alanine CH3 Glycine H
Aspartic acid CH2COOH Serine CH2OH
Glutamine (CH2)2CONH2 Valine CH(CH3)2
Use the information in Table 1 to identify the amino acid joined to alanine in
Figure 2.
[1 mark]
Question 1 continues on the next page
Turn over ►
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, 4
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outside the
0 1 . 4 Figure 3 represents the structure of an antibody. box
Figure 3
The total number of amino acids in a particular antibody molecule is 1322
The ratio of amino acids in the heavy chains to the amino acids in the light chains is
2.13 : 1
Calculate how many amino acids there are in one heavy chain.
Give your answer to the nearest whole number.
[2 marks]
amino acids 6
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IB/M/Jun25/7401/1
ATTACHED) Monday 12 May 2025 [VERIFIED]
Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
AS
BIOLOGY
Paper 1
Monday 12 May 2025 Morning Time allowed: 1 hour 30 minutes
Materials For Examiner’s Use
For this paper you must have:
Question Mark
a ruler with millimetre measurements
a scientific calculator. 1
2
Instructions
3
Use black ink or black ball-point pen.
Fill in the boxes at the top of this page. 4
Answer all questions. 5
You must answer the questions in the spaces provided. Do not write 6
outside the box around each page or on blank pages.
7
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). 8
Show all your working. 9
Do all rough work in this book. Cross through any work you do not want to be marked.
TOTAL
Information
The marks for the questions are shown in brackets.
The maximum mark for this paper is 75.
tyrionpapers.com for m o r e resources
7 4 0 1 /1
IB/M/Jun25/G4002/V5
, 2
Do not write
outside the
Answer all questions in the spaces provided. box
0 1 . 1 Figure 1 shows the structure of the amino acid alanine.
Figure 1
Name the NH2 and COOH groups in the amino acid. [1 mark]
NH2
COOH
Figure 2 shows the molecule formed from alanine and another amino acid.
Figure 2
0 1 . 2 Name the type of bond and the type of molecule formed when the two amino acids in
Figure 2 are joined.
[2 marks]
Type of bond
Type of molecule
tyrionpapers.com for more resources
IB/M/Jun25/7401/1
, 3
Do not write
outside the
0 1 . 3 Table 1 shows the R groups of six different amino acids. box
Table 1
Amino acid R group Amino acid R group
Alanine CH3 Glycine H
Aspartic acid CH2COOH Serine CH2OH
Glutamine (CH2)2CONH2 Valine CH(CH3)2
Use the information in Table 1 to identify the amino acid joined to alanine in
Figure 2.
[1 mark]
Question 1 continues on the next page
Turn over ►
tyrionpapers.com for more resources
IB/M/Jun25/7401/1
, 4
Do not write
outside the
0 1 . 4 Figure 3 represents the structure of an antibody. box
Figure 3
The total number of amino acids in a particular antibody molecule is 1322
The ratio of amino acids in the heavy chains to the amino acids in the light chains is
2.13 : 1
Calculate how many amino acids there are in one heavy chain.
Give your answer to the nearest whole number.
[2 marks]
amino acids 6
tyrionpapers.com for more resources
IB/M/Jun25/7401/1
