BIOLOGY-YBI11 · Pearson Edexcel International A Level
BIOLOGY-YBI11/12
Paper 1
Biology · Winter 2026 · Variant 2
Relative difficulty
Analysis source: Pearson Edexcel
Analysis aligned to the official syllabus and assessment design.
4.0 / 5
440
550 min
Microbiology, Epidemiology, Immunity and Pathogenic Defense Mechanisms
Cohort performance
Session statistics from official examination reports
Total marks
440
Duration
550 min
Session difficulty
4.0 / 5
Key examiner messages
Top priorities from the principal examiner before you revise
High-scoring candidates demonstrated exceptional precision in mathematical calculations—such as magnification conversions, tumor volume estimations to correct significant figures, and the application of the Hardy-Weinberg equation.
However, many candidates lost marks on Level-of-Response (6-mark) questions by failing to balance description (what the data shows) with scientific explanation (the underlying biological mechanisms).
For instance, in the Unit 2 DNA methylation question, weaker scripts confused histone modification with direct cytosine methylation, whereas top-tier answers explicitly linked methyltransferase suppression to chromatin coiling (heterochromatin) and the subsequent prevention of RNA polymerase binding.
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.
Mathematical
Weight: 8100%Hypothesis & Experiments
Weight: 788%Theoretical Recall
Weight: 675%Graphical Analysis
Weight: 450%Synoptic Comprehension
Weight: 225%
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.
Apply knowledge to an unfamiliar context; concise, practical points score best.
Match the expected response style for “Name” questions.
Match the expected response style for “Comment” questions.
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
Microbiology, Immunity and Forensics
71 marks this session
Plant Structure and Function, Biodiversity and Conservation
69 marks this session
Energy Flow, Ecosystems and the Environment
60 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
WBI11/01A - Unit 1: Molecules, Diet, Transport and Health: WBI12/01A - Unit 2: Cells, Development, Biodiversity and Conservation: WBI13/01A - Unit 3: Practical Skills in Biology I: WBI14/01A - Unit 4: Energy, Environment, Microbiology and Immunity: WBI15/01A - Unit 5: Respiration, Internal Environment, Coordination and Gene Technology: WBI16/01A - Unit 6: Practical Skills in Biology II:
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
Microbiology, Immunity and Forensics
71 marks this session
Practise in RevuiPlant Structure and Function, Biodiversity and Conservation
69 marks this session
Practise in RevuiEnergy Flow, Ecosystems and the Environment
60 marks this session
Practise in RevuiSelf-diagnostic checklist
Key actions before you sit this paper — copy and tick off as you revise
- 1Message
High-scoring candidates demonstrated exceptional precision in mathematical calculations—such as magnification conversions, tumor volume estimations to correct significant figures, and the application of the Hardy-Weinberg equation.
- 2Message
However, many candidates lost marks on Level-of-Response (6-mark) questions by failing to balance description (what the data shows) with scientific explanation (the underlying biological mechanisms).
- 3Message
For instance, in the Unit 2 DNA methylation question, weaker scripts confused histone modification with direct cytosine methylation, whereas top-tier answers explicitly linked methyltransferase suppression to chromatin coiling (heterochromatin) and the subsequent prevention of RNA polymerase binding.
Teacher briefing pack
One-page session summary for tutors and classroom review
Winter 2026 2026
Biology
High-scoring candidates demonstrated exceptional precision in mathematical calculations—such as magnification conversions, tumor volume estimations to correct significant figures, and the application of the Hardy-Weinberg equation. However, many candidates lost marks on Level-of-
High-scoring candidates demonstrated exceptional precision in mathematical calculations—such as magnification conversions, tumor volume estimations to correct significant figures, and the application of the Hardy-Weinberg equation.
However, many candidates lost marks on Level-of-Response (6-mark) questions by failing to balance description (what the data shows) with scientific explanation (the underlying biological mechanisms).
For instance, in the Unit 2 DNA methylation question, weaker scripts confused histone modification with direct cytosine methylation, whereas top-tier answers explicitly linked methyltransferase suppression to chromatin coiling (heterochromatin) and the subsequent prevention of RNA polymerase binding.
- Total marks
- 440
- Duration
- 550 min
- Session difficulty
- 4.0 / 5
Session analysis
High-scoring candidates demonstrated exceptional precision in mathematical calculations—such as magnification conversions, tumor volume estimations to correct significant figures, and the application of the Hardy-Weinberg equation. However, many candidates lost marks on Level-of-Response (6-mark) questions by failing to balance description (what the data shows) with scientific explanation (the underlying biological mechanisms). For instance, in the Unit 2 DNA methylation question, weaker scripts confused histone modification with direct cytosine methylation, whereas top-tier answers explicitly linked methyltransferase suppression to chromatin coiling (heterochromatin) and the subsequent prevention of RNA polymerase binding.
Updated Jun 12, 2026
Paper breakdown
WBI11/01A - Unit 1: Molecules, Diet, Transport and Health: WBI12/01A - Unit 2: Cells, Development, Biodiversity and Conservation: WBI13/01A - Unit 3: Practical Skills in Biology I: WBI14/01A - Unit 4: Energy, Environment, Microbiology and Immunity: WBI15/01A - Unit 5: Respiration, Internal Environment, Coordination and Gene Technology: WBI16/01A - Unit 6: Practical Skills in Biology II:
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.
77% 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 & Structure Questions
242·48·55%
Experimental Design & Practical Skills
80·12·18%
Calculations & Mathematical Modelling
42·18·10%
Multiple Choice & Objective Questions
40·28·9%
Level of Response
(Extended Writing)
36·6·8%
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.
Cardiac Cycle Pressure Changes and Arterial System Dynamics
85%85%
Plant Stem Mineral Nutrition and Photosynthetic Pigment Chromatography
80%80%
Somatic and Autonomic Nervous System Pathways with Muscle Contraction
75%75%
Examiner notes & key calculations
- Meiosis Precision: Students frequently lose marks by quoting the wrong stage for genetic variation; crossing over must be pinned to Prophase I and independent assortment to Metaphase I.
- Exponential Growth in PCR: Simply stating that DNA 'increases rapidly' was insufficient; candidates must specify that the DNA quantity doubles with each cycle.
- Variable Control in Practical Designs: In both Unit 3 and Unit 6, when devising procedures, failing to specify a range of at least five distinct values for the independent variable remains a persistent error.
- Statistical Rigor: In Unit 6 Q3, misinterpreting the comparison between calculated t-values and critical tables led to incorrect conclusions regarding the null hypothesis.
Analysis is paraphrased for study purposes. Always verify against the official examiner report and mark scheme.