Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
A-level
BIOLOGY
Paper 2
Friday 13 June 2025 Morning Time allowed: 2 hours
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.
4
• Fill in the boxes at the top of this page.
• 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 10
to be marked.
TOTAL
Information
• The marks for the questions are shown in brackets.
• The maximum mark for this paper is 91.
*jun257402201*
IB/M/Jun25/G4007/V5 7402/2
, 2
Do not write
outside the
Answer all questions in the spaces provided. box
0 1 . 1 In the following passage, the numbered spaces can be filled with biological terms.
Glycolysis is the first stage of respiration. It occurs in the (1) of cells and is
an anaerobic process. Glycolysis involves the (2) of glucose to glucose
phosphate, using ATP. The oxidation of triose phosphate to (3) results in
the net gain of ATP and reduced (4) .
Write the correct biological term beside each number below that matches the space in
the passage.
[2 marks]
1
2
3
4
0 1 . 2 The equation for the aerobic respiration of glucose is:
C6H12O6 + 6 O2 6 CO2 + 6 H2O
Six carbon dioxide molecules are produced from each glucose molecule.
Use your knowledge of the link reaction and Krebs cycle to explain why.
[2 marks]
*02*
IB/M/Jun25/7402/2
, 3
Do not write
outside the
0 1 . 3 An inhibitor of the electron transfer chain was added to aerobically respiring yeast box
cells.
As aerobic respiration was inhibited, the following changes occurred:
• oxygen uptake decreased
• ATP production decreased
• ethanol was produced.
Explain the changes in the yeast cells following the addition of the inhibitor.
[3 marks]
Oxygen uptake decreased
ATP production decreased
Ethanol was produced
7
Turn over for the next question
Turn over ►
*03*
IB/M/Jun25/7402/2
, 4
Do not write
outside the
0 2 . 1 What term is used to describe the maintenance of a stable internal environment? box
[1 mark]
0 2 . 2 A high blood glucose concentration can cause dehydration of body cells.
Explain why.
Do not refer to ADH or the role of the kidneys in your answer.
[2 marks]
0 2 . 3 The hormone glucagon is involved in maintaining a stable blood glucose
concentration.
Which is not a result of the action of glucagon?
Tick () one box.
[1 mark]
Activation of a protein kinase enzyme
Activation of cyclic AMP hydrolysis
Gluconeogenesis
Glycogenolysis
*04*
IB/M/Jun25/7402/2
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
A-level
BIOLOGY
Paper 2
Friday 13 June 2025 Morning Time allowed: 2 hours
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.
4
• Fill in the boxes at the top of this page.
• 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 10
to be marked.
TOTAL
Information
• The marks for the questions are shown in brackets.
• The maximum mark for this paper is 91.
*jun257402201*
IB/M/Jun25/G4007/V5 7402/2
, 2
Do not write
outside the
Answer all questions in the spaces provided. box
0 1 . 1 In the following passage, the numbered spaces can be filled with biological terms.
Glycolysis is the first stage of respiration. It occurs in the (1) of cells and is
an anaerobic process. Glycolysis involves the (2) of glucose to glucose
phosphate, using ATP. The oxidation of triose phosphate to (3) results in
the net gain of ATP and reduced (4) .
Write the correct biological term beside each number below that matches the space in
the passage.
[2 marks]
1
2
3
4
0 1 . 2 The equation for the aerobic respiration of glucose is:
C6H12O6 + 6 O2 6 CO2 + 6 H2O
Six carbon dioxide molecules are produced from each glucose molecule.
Use your knowledge of the link reaction and Krebs cycle to explain why.
[2 marks]
*02*
IB/M/Jun25/7402/2
, 3
Do not write
outside the
0 1 . 3 An inhibitor of the electron transfer chain was added to aerobically respiring yeast box
cells.
As aerobic respiration was inhibited, the following changes occurred:
• oxygen uptake decreased
• ATP production decreased
• ethanol was produced.
Explain the changes in the yeast cells following the addition of the inhibitor.
[3 marks]
Oxygen uptake decreased
ATP production decreased
Ethanol was produced
7
Turn over for the next question
Turn over ►
*03*
IB/M/Jun25/7402/2
, 4
Do not write
outside the
0 2 . 1 What term is used to describe the maintenance of a stable internal environment? box
[1 mark]
0 2 . 2 A high blood glucose concentration can cause dehydration of body cells.
Explain why.
Do not refer to ADH or the role of the kidneys in your answer.
[2 marks]
0 2 . 3 The hormone glucagon is involved in maintaining a stable blood glucose
concentration.
Which is not a result of the action of glucagon?
Tick () one box.
[1 mark]
Activation of a protein kinase enzyme
Activation of cyclic AMP hydrolysis
Gluconeogenesis
Glycogenolysis
*04*
IB/M/Jun25/7402/2
