Mark Scheme (Results)
Summer 2025
Pearson Edexcel International Advanced Level
In Biology (WBI15)
Paper 01 Respiration, Internal Environment,
Coordination, and Gene Technology
,Edexcel and BTEC Qualifications
Edexcel and BTEC qualifications are awarded by Pearson, the UK’s largest awarding body. We
provide a wide range of qualifications including academic, vocational, occupational and specific
programmes for employers. For further information visit our qualifications websites at
www.edexcel.com or www.btec.co.uk. Alternatively, you can get in touch with us using the
details on our contact us page at www.edexcel.com/contactus.
Pearson: helping people progress, everywhere
Pearson aspires to be the world’s leading learning company. Our aim is to help everyone
progress in their lives through education. We believe in every kind of learning, for all kinds of
people, wherever they are in the world. We’ve been involved in education for over 150 years,
and by working across 70 countries, in 100 languages, we have built an international reputation
for our commitment to high standards and raising achievement through innovation in
education. Find out more about how we can help you and your students at:
www.pearson.com/uk
Summer 2025
Question paper log number P78739A
Publications Code WBI15_01_2506_MS
All the material in this publication is copyright
© Pearson Education Ltd 2025
,General Marking Guidance
• All candidates must receive the same
treatment. Examiners must mark the first candidate in
exactly the same way as they mark the last.
• Mark schemes should be applied positively. Candidates
must be rewarded for what they have shown they can
do rather than penalised for omissions.
• Examiners should mark according to the mark scheme
not according to their perception of where the grade
boundaries may lie.
• There is no ceiling on achievement. All marks on the
mark scheme should be used appropriately.
• All the marks on the mark scheme are designed to be
awarded. Examiners should always award full marks if
deserved, i.e. if the answer matches the mark
scheme. Examiners should also be prepared to award
zero marks if the candidate’s response is not worthy of
credit according to the mark scheme.
• Where some judgement is required, mark schemes will
provide the principles by which marks will be awarded
and exemplification may be limited.
• When examiners are in doubt regarding the application
of the mark scheme to a candidate’s response, the team
leader must be consulted.
• Crossed out work should be marked UNLESS the
candidate has replaced it with an alternative response.
, Question Answer Additional guidance Mark
number
1(a) An answer that includes the following points: ACCEPT phonetic spelling
• A dendrite(s) (1) ACCEPT dendron (2)
• B cell body (1) ACCEPT soma/ cell membrane /
centron
IGNORE body cell
• C myelin (sheath(s) (1)
ACCEPT {fatty / lipid} sheath /
Schwann cell / glial cell / axon
IGNORE lipid unqualified
IGNORE sheath unqualified
All 3 correct = 2 marks
1 or 2 correct = 1 mark
Summer 2025
Pearson Edexcel International Advanced Level
In Biology (WBI15)
Paper 01 Respiration, Internal Environment,
Coordination, and Gene Technology
,Edexcel and BTEC Qualifications
Edexcel and BTEC qualifications are awarded by Pearson, the UK’s largest awarding body. We
provide a wide range of qualifications including academic, vocational, occupational and specific
programmes for employers. For further information visit our qualifications websites at
www.edexcel.com or www.btec.co.uk. Alternatively, you can get in touch with us using the
details on our contact us page at www.edexcel.com/contactus.
Pearson: helping people progress, everywhere
Pearson aspires to be the world’s leading learning company. Our aim is to help everyone
progress in their lives through education. We believe in every kind of learning, for all kinds of
people, wherever they are in the world. We’ve been involved in education for over 150 years,
and by working across 70 countries, in 100 languages, we have built an international reputation
for our commitment to high standards and raising achievement through innovation in
education. Find out more about how we can help you and your students at:
www.pearson.com/uk
Summer 2025
Question paper log number P78739A
Publications Code WBI15_01_2506_MS
All the material in this publication is copyright
© Pearson Education Ltd 2025
,General Marking Guidance
• All candidates must receive the same
treatment. Examiners must mark the first candidate in
exactly the same way as they mark the last.
• Mark schemes should be applied positively. Candidates
must be rewarded for what they have shown they can
do rather than penalised for omissions.
• Examiners should mark according to the mark scheme
not according to their perception of where the grade
boundaries may lie.
• There is no ceiling on achievement. All marks on the
mark scheme should be used appropriately.
• All the marks on the mark scheme are designed to be
awarded. Examiners should always award full marks if
deserved, i.e. if the answer matches the mark
scheme. Examiners should also be prepared to award
zero marks if the candidate’s response is not worthy of
credit according to the mark scheme.
• Where some judgement is required, mark schemes will
provide the principles by which marks will be awarded
and exemplification may be limited.
• When examiners are in doubt regarding the application
of the mark scheme to a candidate’s response, the team
leader must be consulted.
• Crossed out work should be marked UNLESS the
candidate has replaced it with an alternative response.
, Question Answer Additional guidance Mark
number
1(a) An answer that includes the following points: ACCEPT phonetic spelling
• A dendrite(s) (1) ACCEPT dendron (2)
• B cell body (1) ACCEPT soma/ cell membrane /
centron
IGNORE body cell
• C myelin (sheath(s) (1)
ACCEPT {fatty / lipid} sheath /
Schwann cell / glial cell / axon
IGNORE lipid unqualified
IGNORE sheath unqualified
All 3 correct = 2 marks
1 or 2 correct = 1 mark
