BIOLOGY-YBI11 · Pearson Edexcel International A Level
BIOLOGY-YBI11/21
Paper 2
Biology · June 2025 · Variant 1
Relative difficulty
Analysis source: Pearson Edexcel
Analysis aligned to the official syllabus and assessment design.
4.0 / 5
90
105 min
Gene Technology, Epigenetics, and Hormonal/Nervous Coordination
Cohort performance
Session statistics from official examination reports
Total marks
90
Duration
105 min
Session difficulty
4.0 / 5
Key examiner messages
Top priorities from the principal examiner before you revise
The Summer 2025 Unit 5 paper (WBI15/01) presented a sophisticated assessment of the upper-level Edexcel specification.
Standing out as a highly conceptual paper, it demanded deep integration of metabolic biochemistry (respiration and muscle action) alongside modern gene technologies (such as CRISPR-Cas9 and epigenetics).
The difficulty was amplified by multi-variable graphs and a dense scientific article focusing on Y-chromosome depletion and its physiological links to cardiac disease and cancer.
Question difficulty map
How candidates performed on each question in this series
No data available in official reports
Assessment objectives
Skill and AO weighting from official examiner commentary
Skill weighting
Shows the skill mix this paper tested most heavily.
Biological
Weight: 6100%Recall
Weight: 583%Analysis & T
Weight: 467%Scientific Synthesis
Weight: 350%Mathematical
Weight: 117%
Method marks watchlist
Where working, steps, or method marks were commonly lost
No data available in official reports
Recurring mistakes across years
Themes examiners flag in multiple recent sessions for this subject
No data available in official reports
Question choice intelligence
Mean scores and popularity for optional questions (HKDSE electives)
No data available in official reports
Level exemplars
What candidate scripts at each grade level looked like
No data available in official reports
Grade & admission context
How marks relate to grade thresholds and entry standards
Report type
Examiner report — national grade boundaries and question-level commentary
Level A*
Approx. 90% of maximum mark
Level A
Approx. 80% of maximum mark
Level B
Approx. 70% of maximum mark
Level C
Approx. 60% of maximum mark
Level D
Approx. 50% of maximum mark
Level E
Approx. 40% of maximum mark
Deep insights
What top candidates did
Techniques and approaches examiners rewarded in this series
No data available in official reports
Command word playbook
How to match each command word to the expected response style
Give reasons and link mechanism to outcome; each point needs a because/so chain.
State features in sequence or list observable properties — do not explain causes unless asked.
Show formula, substitution, and unit; method marks need visible working.
Present multiple perspectives with evidence; balance breadth and depth.
Match the expected response style for “Comment” questions.
Apply knowledge to an unfamiliar context; concise, practical points score best.
Time traps
Sections where candidates spent disproportionate time relative to marks
No data available in official reports
Syllabus traceability
Topics linked to questions and mark weighting in this session
Coordination, Response and Gene Technology
61 marks this session
Respiration, Muscles and the Internal Environment
29 marks this session
MCQ trap analytics
Commonly chosen wrong options from examiner commentary
No data available in official reports
Topic heatmap across years
Mark concentration by topic and exam year for this subject
Mark intensity
Plant Structure and Function, Biodiversity and Conservation
Coordination, Response and Gene Technology
Membranes, Proteins, DNA and Gene Expression
Respiration, Muscles and the Internal Environment
Microbiology, Immunity and Forensics
Molecules, Transport and Health
Energy Flow, Ecosystems and the Environment
Difficulty trend
How session difficulty has shifted across recent years
Paper comparison
Marks and duration breakdown across papers in this session
Unit 5: Respiration, Internal Environment, Coordination and Gene Technology (WBI15/01):
Marks you can still earn
Where valid approaches outside the mark scheme may still gain credit
No data available in official reports
Practise what examiners flagged
Target weak topics from this report inside the Revui app
Coordination, Response and Gene Technology
61 marks this session
Practise in RevuiRespiration, Muscles and the Internal Environment
29 marks this session
Practise in RevuiBiology
Session priority from examiner report
Practise in RevuiSelf-diagnostic checklist
Key actions before you sit this paper — copy and tick off as you revise
- 1Message
The Summer 2025 Unit 5 paper (WBI15/01) presented a sophisticated assessment of the upper-level Edexcel specification.
- 2Message
Standing out as a highly conceptual paper, it demanded deep integration of metabolic biochemistry (respiration and muscle action) alongside modern gene technologies (such as CRISPR-Cas9 and epigenetics).
- 3Message
The difficulty was amplified by multi-variable graphs and a dense scientific article focusing on Y-chromosome depletion and its physiological links to cardiac disease and cancer.
Teacher briefing pack
One-page session summary for tutors and classroom review
June 2025 2025
Biology
The Summer 2025 Unit 5 paper (WBI15/01) presented a sophisticated assessment of the upper-level Edexcel specification. Standing out as a highly conceptual paper, it demanded deep integration of metabolic biochemistry (respiration and muscle action) alongside modern gene technolog
The Summer 2025 Unit 5 paper (WBI15/01) presented a sophisticated assessment of the upper-level Edexcel specification.
Standing out as a highly conceptual paper, it demanded deep integration of metabolic biochemistry (respiration and muscle action) alongside modern gene technologies (such as CRISPR-Cas9 and epigenetics).
The difficulty was amplified by multi-variable graphs and a dense scientific article focusing on Y-chromosome depletion and its physiological links to cardiac disease and cancer.
- Total marks
- 90
- Duration
- 105 min
- Session difficulty
- 4.0 / 5
Session analysis
The Summer 2025 Unit 5 paper (WBI15/01) presented a sophisticated assessment of the upper-level Edexcel specification. Standing out as a highly conceptual paper, it demanded deep integration of metabolic biochemistry (respiration and muscle action) alongside modern gene technologies (such as CRISPR-Cas9 and epigenetics). The difficulty was amplified by multi-variable graphs and a dense scientific article focusing on Y-chromosome depletion and its physiological links to cardiac disease and cancer.
Updated Jun 12, 2026
Paper breakdown
Unit 5: Respiration, Internal Environment, Coordination and Gene Technology (WBI15/01):
Top chapters
Exam structure insights
Marks by chapter
See where the marks were concentrated so revision time goes to the highest-value topics.
Mark accessibility
Estimate which marks were basic, mid-level, or high-difficulty.
74% within easy or medium reach
Command word frequency
Spot common command words so answers match the expected response style.
Question type mix
Compare the mark share of each paper section and question type.
Short Answer
46·22·51%
Structured Essay / Long Answer
28·4·31%
Multiple Choice
8·8·9%
Mathematical/Calculation
8·4·9%
Study ROI
Bigger bubbles recur more often; higher bubbles carry more marks, helping you rank revision priorities.
Next-year prediction
Topics worth watching next year, with the reason shown directly below each bar.
Myofibrils, Muscle Contraction (Sliding Filament Theory) and Muscle Fatigue
90%90%
Osmoregulation, Loop of Henle and Kidney Nephron Structure
85%85%
Paper analysis
The Summer 2025 Unit 5 paper (WBI15/01) presented a sophisticated assessment of the upper-level Edexcel specification. Standing out as a highly conceptual paper, it demanded deep integration of metabolic biochemistry (respiration and muscle action) alongside modern gene technologies (such as CRISPR-Cas9 and epigenetics). The difficulty was amplified by multi-variable graphs and a dense scientific article focusing on Y-chromosome depletion and its physiological links to cardiac disease and cancer.
Analysis is paraphrased for study purposes. Always verify against the official examiner report and mark scheme.