BIOLOGY-A-H420 · Cambridge OCR A Level
BIOLOGY-A-H420/21
Paper 2
Biology A - H420 · 2024 · Variant 1
Relative difficulty
Analysis source: OCR
Analysis aligned to the official syllabus and assessment design.
3.8 / 5
270
360 min
Genomics, biotechnology, and cellular mechanics
Cohort performance
Session statistics from official examination reports
Total marks
270
Duration
360 min
Session difficulty
3.8 / 5
Key examiner messages
Top priorities from the principal examiner before you revise
The June 2024 series for OCR A Level Biology A (H420) presents a robust challenge, earning a solid 4 out of 5 stars for difficulty.
This is driven by several multi-step mathematical calculations, extensive data interpretation tasks (including twin studies and threat index evaluations), and challenging experimental design scenarios.
Students had to demonstrate deep synoptic connections across diverse syllabus areas, making this a highly demanding assessment.
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.
Recall and Knowledge
Weight: 5100%Terminology
Weight: 480%Analysis and
Weight: 360%Experimental
Weight: 240%Mathematical and
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. 69% of maximum mark
Level A
Approx. 59% of maximum mark
Level B
Approx. 50% of maximum mark
Level C
Approx. 42% of maximum mark
Level D
Approx. 33% of maximum mark
Level E
Approx. 24% 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.
Match the expected response style for “State” questions.
Apply knowledge to an unfamiliar context; concise, practical points score best.
Name or point to the specific feature asked for — avoid extra explanation.
Weigh arguments for and against with evidence; end with a supported judgement.
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
Manipulating genomes
23 marks this session
Cell division, cell diversity and cellular organisation
23 marks this session
Photosynthesis
20 marks this session
Cloning and biotechnology
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
Manipulating genomes
23 marks this session
Practise in RevuiCell division, cell diversity and cellular organisation
23 marks this session
Practise in RevuiPhotosynthesis
20 marks this session
Practise in RevuiCloning and biotechnology
18 marks this session
Practise in RevuiSelf-diagnostic checklist
Key actions before you sit this paper — copy and tick off as you revise
- 1Message
The June 2024 series for OCR A Level Biology A (H420) presents a robust challenge, earning a solid 4 out of 5 stars for difficulty.
- 2Message
This is driven by several multi-step mathematical calculations, extensive data interpretation tasks (including twin studies and threat index evaluations), and challenging experimental design scenarios.
- 3Message
Students had to demonstrate deep synoptic connections across diverse syllabus areas, making this a highly demanding assessment.
Teacher briefing pack
One-page session summary for tutors and classroom review
2024 2024
Biology A - H420
The June 2024 series for OCR A Level Biology A (H420) presents a robust challenge, earning a solid 4 out of 5 stars for difficulty. This is driven by several multi-step mathematical calculations, extensive data interpretation tasks (including twin studies and threat index evaluat
The June 2024 series for OCR A Level Biology A (H420) presents a robust challenge, earning a solid 4 out of 5 stars for difficulty.
This is driven by several multi-step mathematical calculations, extensive data interpretation tasks (including twin studies and threat index evaluations), and challenging experimental design scenarios.
Students had to demonstrate deep synoptic connections across diverse syllabus areas, making this a highly demanding assessment.
- Total marks
- 270
- Duration
- 360 min
- Session difficulty
- 3.8 / 5
Session analysis
The June 2024 series for OCR A Level Biology A (H420) presents a robust challenge, earning a solid 4 out of 5 stars for difficulty. This is driven by several multi-step mathematical calculations, extensive data interpretation tasks (including twin studies and threat index evaluations), and challenging experimental design scenarios. Students had to demonstrate deep synoptic connections across diverse syllabus areas, making this a highly demanding assessment.
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.
72% 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.
Structured Short Answer
204·82·76%
Level of Response Essay
36·6·13%
Multiple Choice Questions
(MCQ)
30·30·11%
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.
Neuronal communication
95%95%
Hormonal communication and cell signaling
85%85%
Respiration pathways
80%80%
Difficulty Verdict
The June 2024 series for OCR A Level Biology A (H420) presents a robust challenge, earning a solid 4 out of 5 stars for difficulty. This is driven by several multi-step mathematical calculations, extensive data interpretation tasks (including twin studies and threat index evaluations), and challenging experimental design scenarios. Students had to demonstrate deep synoptic connections across diverse syllabus areas, making this a highly demanding assessment.
Examiner notes & key calculations
- Standard Deviation Misinterpretation: In questions evaluating data support, many candidates noticed changes in the mean but completely failed to comment on the overlapping or non-overlapping of standard deviation error bars.
- Chemical specificity: Generalizing terms (such as writing simply 'glycosidic bond' when 'alpha-1,4-glycosidic bond' was explicitly required, or confusing alpha and beta links) resulted in zero credit.
- Lack of comparative language: When explaining the differences between arteriole and venule pressures, or comparing bird and mammal threats, candidates often listed isolated values instead of making direct comparative statements.
Analysis is paraphrased for study purposes. Always verify against the official examiner report and mark scheme.