B1.2.5—Effect of pH and temperature
Protein function depends on shape, so high temperature or unsuitable pH can denature proteins by disrupting stabilizing bonds and active sites.
- Syllabus
- First assessment 2025
- Objective
- B1.2.5
- Level
- HL
Exam analysis
Chance of appearing2%of analysed past papers
Latest appearanceNovember 2021
Most common paperPaper1
Typical marks1–4
Common command terms
- Outline
- Explain
- Identify
Scoring notes
- Common mistake
- Claiming denaturation changes the amino-acid sequence.
Recent exam appearances
November 2021Paper2 ["HL"] · TZ08(a)[ 4 ]B1.2.5—Effect of pH and temperature
May 2017Paper1 ["HL"] · TZ29[ 1 ]B1.2.5—Effect of pH and temperature
Practice this objective
Coverage 2017–2021 · Updated 15 Jul 2026
Concept essentials
- Denaturation changes protein conformation and can remove biological function.
- High temperature and unsuitable pH can disrupt bonds within proteins.
- Enzyme denaturation changes the active site and reduces substrate binding.
- Denaturation usually leaves the primary amino-acid sequence unchanged.