BIOLOGY-A-H420 · Cambridge OCR A Level
BIOLOGY-A-H420/21
Paper 2
Biology A - H420 · 2022 · Variant 1
Relative difficulty
Analysis source: OCR
Analysis aligned to the official syllabus and assessment design.
4.1 / 5
270
360 min
Cloning and biotechnology (Aseptic technique, serial dilutions, fermentation processes, single-cell protein production, and animal cloning methods)
Cohort performance
Session statistics from official examination reports
Total marks
270
Duration
360 min
Session difficulty
4.1 / 5
Key examiner messages
Top priorities from the principal examiner before you revise
Many students found success on standard recall questions, such as identifying the Calvin cycle intermediates or describing the basics of the sliding filament model.
However, a significant number of marks were lost on practical and calculation-heavy questions:
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 & Calculation
Weight: 5100%Experimental
Weight: 480%Structured Explanation
Weight: 360%Interpretation
Weight: 120%
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. 68% of maximum mark
Level A
Approx. 58% of maximum mark
Level B
Approx. 48% of maximum mark
Level C
Approx. 39% of maximum mark
Level D
Approx. 29% of maximum mark
Level E
Approx. 19% 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.
Weigh arguments for and against with evidence; end with a supported judgement.
Apply knowledge to an unfamiliar context; concise, practical points score best.
Match the expected response style for “State” questions.
Name or point to the specific feature asked for — avoid extra explanation.
Match the expected response style for “Outline” 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
Cloning and biotechnology
42 marks this session
Biodiversity
26 marks this session
Plant and animal responses
24 marks this session
Biological molecules
18 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
Cloning and biotechnology
Biodiversity
Plant and animal responses
Manipulating genomes
Cell division, cell diversity and cellular organisation
Photosynthesis
Respiration
Transport in animals
Difficulty trend
How session difficulty has shifted across recent years
Paper comparison
Marks and duration breakdown across papers in this session
H420/01 Biological processes: H420/02 Biological diversity: H420/03 Unified biology:
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
Cloning and biotechnology
42 marks this session
Practise in RevuiBiodiversity
26 marks this session
Practise in RevuiPlant and animal responses
24 marks this session
Practise in RevuiBiological molecules
18 marks this session
Practise in RevuiSelf-diagnostic checklist
Key actions before you sit this paper — copy and tick off as you revise
- 1Message
Many students found success on standard recall questions, such as identifying the Calvin cycle intermediates or describing the basics of the sliding filament model.
- 2Message
However, a significant number of marks were lost on practical and calculation-heavy questions:
Teacher briefing pack
One-page session summary for tutors and classroom review
2022 2022
Biology A - H420
Many students found success on standard recall questions, such as identifying the Calvin cycle intermediates or describing the basics of the sliding filament model. However, a significant number of marks were lost on practical and calculation-heavy questions:
Many students found success on standard recall questions, such as identifying the Calvin cycle intermediates or describing the basics of the sliding filament model.
However, a significant number of marks were lost on practical and calculation-heavy questions:
- Total marks
- 270
- Duration
- 360 min
- Session difficulty
- 4.1 / 5
Session analysis
Many students found success on standard recall questions, such as identifying the Calvin cycle intermediates or describing the basics of the sliding filament model. However, a significant number of marks were lost on practical and calculation-heavy questions:
Updated Jun 14, 2026
Paper breakdown
H420/01 Biological processes: H420/02 Biological diversity: H420/03 Unified biology:
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.
68% 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 / Structural Questions
210·68·78%
Multiple Choice Questions
(MCQs)
30·30·11%
Extended Level-of-Response (Starred) Questions
30·5·11%
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.
Patterns of inheritance (Monohybrid, Dihybrid, Codominance, Epistasis)
90%90%
Neuronal Communication (Action potentials, myelin sheath, synapse transmission)
85%85%
Ecosystems and Nutrient Cycling (Nitrogen / Carbon cycles, ecological succession)
80%80%
Analysis is paraphrased for study purposes. Always verify against the official examiner report and mark scheme.