Edexcel International AS Level Biology Paper 1 2026 with Mark Scheme (PDF)

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Pearson Edexcel International Advanced Level
Tuesday 5 May 2026
Mark Scheme (Results)
Afternoon (Time: 1 hour 30 minutes) Paper
reference WBI11/01
Biology  


International Advanced Subsidiary/Advanced Level
UNIT 1: Molecules, Diet, Transport and Health Summer 2026
You must have: Total Marks
Pearson Edexcel International Advanced Subsidiary Level
Scientific calculator, ruler, HB pencil in Biology

Instructions WBI11/01
•• Use black ink or ball-point pen.
Fill in the boxes at the top of this page with your name,
centre number and candidate number.
•• Answer all questions.
Answer the questions in the spaces provided
– there may be more space than you need.
•• Calculators may be used.
You must show all your working out with your answer clearly identified at the
end of your solution.

Information
•• The total mark for this paper is 80.
The marks for each question are shown in brackets
– use this as a guide as to how much time to spend on each question.
• structure
In questions marked with an asterisk (*), marks will be awarded for your ability to
your answer logically, showing how the points you make are related or
follow on from each other where appropriate.

Advice
•• Read each question carefully before you start to answer it.
Try to answer every question.
• Check your answers if you have time at the end. Turn over


P79211APearson Education Ltd.
P:1/1/1/1/1/1/
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, Answer ALL questions. Write your answers in the spaces provided. Edexcel and BTEC Qualifications
Some questions must be answered with a cross in a box . If you change your mind about an




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answer, put a line through the box and then mark your new answer with a cross .
Edexcel and BTEC qualifications are awarded by Pearson, the UK’s
1 (a) Read through the following description of osmosis. largest awarding body. We provide a wide range of qualifications
including academic, vocational, occupational and specific
Complete the description by writing the most appropriate word or words on the
dotted lines. programmes for employers. For further information visit our
(4) qualifications websites at or .
Alternatively, you can get in touch with us using the details on our
Osmosis is the movement of . ............................................................................................ water molecules
contact us page at
through a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ......................................... cell membrane,

............ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............ a water potential gradient.


The water potential gradient is affected by the .............................................................................................
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of solutes dissolved in the cytoplasm.
Pearson aspires to be the world’s leading learning company. Our aim is to help
(b) The water potential of a plant tissue can be calculated using the equation: 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
water potential = osmotic potential + turgor pressure
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Calculate the water potential of a plant tissue with a turgor pressure of 150 kPa 100 languages, we have built an international reputation for our commitment to
and an osmotic potential of –398 kPa. high standards and raising achievement through innovation in education. Find
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Answer .................................... . . . . . . . . . . . . . . . . . . . . . . . . . . kPa
(Total for Question 1 = 5 marks)

Summer 2026
Question Paper Log Number P79211A
Publication Code WBI11_01_2606
All the material in this publication is
Pearson Education Ltd 2026




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, General Marking Guidance
2 The photograph shows fruit from a papaya plant.
• All candidates must receive the same treatment. Examiners must mark the
first candidate in exactly the same way as they mark the last.
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• 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
(Source: funkyfood London - Paul Williams / Alamy Stock Photo) should always award full marks if deserved, i.e. if the answer matches the
This fruit contains an enzyme called papain. 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
Papain breaks down proteins into peptides and amino acids.
scheme.
(a) Name the type of reaction that breaks down protein into peptides and • Where some judgement is required, mark schemes will provide the
amino acids. principles by which marks will be awarded and exemplification may be
(1)
limited.
................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • When examiners are in doubt regarding the application of the mark scheme
to a candidate’s response, the team leader must be consulted.
(b) The diagram shows a papain molecule and part of a protein molecule in a beaker.
• Crossed out work should be marked UNLESS the candidate has replaced it
with an alternative response.




part of
a protein
molecule


papain




Complete the diagram to show the two stages in the breakdown of this protein to
produce a peptide and one amino acid.
(2)




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, Question Answer Additional guidance Mark
number
The graph shows the free energy change when protein in a solution with no 1(a) A description that makes reference to the following points:
papain present breaks down into its products.
• free (1) ACCEPT unrestricted / polar




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Free energy ACCEPT {selectively / semi} permeable
• partially permeable (1)

IGNORE along / across / through / with
• down (1) DO NOT ACCEPT up / against

ACCEPT number / osmotic concentration /
• concentration / mass (1) osmolarity
IGNORE solubility / amount (4)




Question Answer Additional guidance Mark
Time of reaction
number
1(b)
Complete the graph to show the free energy change when papain is present in
the protein solution.
• - 248 (kPa) (1) (1)
(2)



Question Answer Additional guidance Mark
number
2(a)
(Total for Question 2 = 5 marks)
• hydrolysis (reaction) (1)
ACCEPT phonetic spellings / catabolic /
proteolysis
DO NOT ACCEPT condensation / (1)
polymerization / denaturation




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