Biology A (Salters-Nuffield) A-Level
Pr and Pfr
What Pr and Pfr means in Biology A (Salters-Nuffield) A-Level, as defined for Pearson Edexcel.
Definition of Pr and Pfr
Check what you remember
Read the wording for your board, then hide it and explain Pr and Pfr in your own words. Rough notes are fine. This is a self-check, with no mark or grade.
Reference: Pearson Edexcel
The two interconvertible forms of phytochrome; Pfr accumulates in red light and reverts to Pr in darkness or far-red light.
Topics that use Pr and Pfr
- Topic 8: Grey Matter (Pearson Edexcel A-Level)
Related terms
- Animal experiments
- Animal models in neuroscience research
- Antagonistic muscle action
- Autonomic control of the pupil
- Benefits
- Cell signalling
- Cerebral hemispheres
- Co-ordination
Using Pr and Pfr in the exam
Check the command word and mark scheme for your exact question. After comparing your explanation with the reference, use the term in an answer on the linked topic. This practice does not predict an exam mark.
Practise Biology A (Salters-Nuffield) questions
Create a free account to answer exam-style questions on this topic and get feedback on your answers.
Start free
All Biology A (Salters-Nuffield) A-Level termsA week of Premium from your first lesson · Then the free plan continues · No card, no charge