IB Biology HL · 2025
4.5 Gene expression
6 past paper questions from 4 papers across 2 exam sessions. See what repeats, then practise the same skills with AI marking.
Original Exam Vault questions with AI markscheme feedback for this topic.
HL archive · 2025 to 2026
4.5 Gene expression
Latest exam session: May 2026
- questions
- 6
- questions
- papers
- 4
- papers
- exam sessions
- 2
- exam sessions
- micro-topics
- 5
Micro-topics in 4.5 Gene expression
In syllabus order. The ring is the share of papers each appears in.
4.5.1
Gene expression and why cells differ
1 question · in 13% of papersAppears in 1 of the 8 Biology HL papers analysed (13%), at least once each.
Occasionallast May 25 P2 TZ3
4.5.2
Regulation of transcription (transcription factors)
2 questions · in 25% of papersAppears in 2 of the 8 Biology HL papers analysed (25%), at least once each.
Frequently testedlast May 26 P1 TZA
4.5.3
Epigenetics: methylation and histone modification
1 question · in 13% of papersAppears in 1 of the 8 Biology HL papers analysed (13%), at least once each.
Occasionallast May 25 P1 TZ2
4.5.4
Environmental influence and epigenetic inheritance
1 question · in 13% of papersAppears in 1 of the 8 Biology HL papers analysed (13%), at least once each.
Occasionallast May 26 P1 TZA
4.5.5
Mutations versus epigenetic change; measuring expression
1 question · in 13% of papersAppears in 1 of the 8 Biology HL papers analysed (13%), at least once each.
Occasionallast May 25 P2 TZ3
Exam pattern
How often each micro-topic has been examined, year by year. Each label is explained under the grid.
Does it repeat?
Top 4 of 5 micro-topics for the next sitting. Numbers are questions per year.
fewermore
| Micro-topic | 2025 | 2026 |
|---|---|---|
| 1Regulation of transcription (transcription factors), 2025: 1 question | 1Regulation of transcription (transcription factors), 2026: 1 question | |
| ·Environmental influence and epigenetic inheritance, 2025: 0 questions | 1Environmental influence and epigenetic inheritance, 2026: 1 question | |
| 1Epigenetics: methylation and histone modification, 2025: 1 question | ·Epigenetics: methylation and histone modification, 2026: 0 questions | |
| 1Mutations versus epigenetic change; measuring expression, 2025: 1 question | ·Mutations versus epigenetic change; measuring expression, 2026: 0 questions |
1 more micro-topics with a free account
- Frequently testedin at least a quarter of all papers, and still appearing in the last two years
- Occasionalin about one paper in ten
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Questions on 4.5 Gene expression, by exam session
Which papers asked about 4.5 Gene expression, and which question numbers. Open a paper to see them highlighted.
May 2026
2 questions across 1 paper
May 2025
3 questions across 3 papers
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Frequently asked questions
Short answers about this page.
Which Biology HL exam sessions are covered for 4.5 Gene expression?
2 exam sessions from 2025 to 2026, the latest May 2026. Every Paper 1 and 2 in every timezone is read and classified in full, which gives 4 papers in this archive.
Which 4.5 Gene expression topic comes up most?
Regulation of transcription (transcription factors) (4.5.2): in 25% of papers, last seen May 26 P1 TZA. Usually "identify", worth about 4 marks in a paper that includes it.
Can I see the original question and mark scheme?
No. The wording belongs to the IB. You get the citation, the marks, the command term and the skill tested, plus our own matched practice questions with worked answers and AI marking.
What do "banker", "due" and "rising" mean?
Banker: examined in at least one sitting in four and still appearing. Due: regular before, but absent for the last two exam sessions. Rising: clearly more common in the last two years. Our classification of real papers, not an IB statistic.
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