Centre Candidate
Surname
Number Number
First name(s) 2
GCE A LEVEL
S25-A400U10-1
A400U10-1
THURSDAY, 5 JUNE 2025 – AFTERNOON
BIOLOGY – A level component 1
Energy for Life
2 hours
For Examiner’s use only
Maximum Mark
Question
Mark Awarded
1. 12
A 4 0 0 U101
2. 14
01
3. 17
4. 21
5. 19
6. 8
ADDITIONAL MATERIALS 7. 9
A calculator and a ruler. Total 100
INSTRUCTIONS TO CANDIDATES
Use black ink or black ball-point pen. Do not use gel pen or correction fluid.
You may use a pencil for graphs and diagrams only.
Write your name, centre number and candidate number in the spaces at the top of this page.
Answer all questions.
Write your answers in the spaces provided in this booklet. If you run out of space, use the additional
page(s) at the back of the booklet, taking care to number the question(s) correctly.
INFORMATION FOR CANDIDATES
The number of marks is given in brackets at the end of each question or part-question.
The assessment of the quality of extended response (QER) will take place in question 7.
The quality of written communication will affect the awarding of marks.
JUN25A400U10101 © WJEC CBAC Ltd. BE/GR*(X24-A400U10-1)
, 2
BLANK PAGE
PLEASE DO NOT WRITE
ON THIS PAGE
02 © WJEC CBAC Ltd. (A400U10-1)
, 3
Examiner
only
Answer all questions.
1. The oxidation of respiratory substrates is catalysed by enzymes. In a series of reactions
hydrogen ions are produced which are transferred to the hydrogen carriers involved in
respiration. These carriers then deliver hydrogen to the site of ATP synthesis.
(a) (i) Name two hydrogen carriers that are involved in aerobic respiration in
mitochondria. [1]
........................................................................................ ........................................................................................
(ii) Describe the role of hydrogen ions in ATP synthesis. [3]
A 4 0 0 U101
03
(iii) Explain why the two hydrogen carriers involved in aerobic respiration result in the
synthesis of different numbers of ATP molecules. [2]
03 © WJEC CBAC Ltd. (A400U10-1) Turn over.
Surname
Number Number
First name(s) 2
GCE A LEVEL
S25-A400U10-1
A400U10-1
THURSDAY, 5 JUNE 2025 – AFTERNOON
BIOLOGY – A level component 1
Energy for Life
2 hours
For Examiner’s use only
Maximum Mark
Question
Mark Awarded
1. 12
A 4 0 0 U101
2. 14
01
3. 17
4. 21
5. 19
6. 8
ADDITIONAL MATERIALS 7. 9
A calculator and a ruler. Total 100
INSTRUCTIONS TO CANDIDATES
Use black ink or black ball-point pen. Do not use gel pen or correction fluid.
You may use a pencil for graphs and diagrams only.
Write your name, centre number and candidate number in the spaces at the top of this page.
Answer all questions.
Write your answers in the spaces provided in this booklet. If you run out of space, use the additional
page(s) at the back of the booklet, taking care to number the question(s) correctly.
INFORMATION FOR CANDIDATES
The number of marks is given in brackets at the end of each question or part-question.
The assessment of the quality of extended response (QER) will take place in question 7.
The quality of written communication will affect the awarding of marks.
JUN25A400U10101 © WJEC CBAC Ltd. BE/GR*(X24-A400U10-1)
, 2
BLANK PAGE
PLEASE DO NOT WRITE
ON THIS PAGE
02 © WJEC CBAC Ltd. (A400U10-1)
, 3
Examiner
only
Answer all questions.
1. The oxidation of respiratory substrates is catalysed by enzymes. In a series of reactions
hydrogen ions are produced which are transferred to the hydrogen carriers involved in
respiration. These carriers then deliver hydrogen to the site of ATP synthesis.
(a) (i) Name two hydrogen carriers that are involved in aerobic respiration in
mitochondria. [1]
........................................................................................ ........................................................................................
(ii) Describe the role of hydrogen ions in ATP synthesis. [3]
A 4 0 0 U101
03
(iii) Explain why the two hydrogen carriers involved in aerobic respiration result in the
synthesis of different numbers of ATP molecules. [2]
03 © WJEC CBAC Ltd. (A400U10-1) Turn over.
