Controlled variables
What Controlled variables means in Biology A-Level, as defined for AQA, OCR.
Definitions of Controlled variables
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Reference: OCR
Include temperature, glucose concentration, yeast mass and pH, with a water bath keeping temperature constant because respiration is enzyme-controlled.
Variables that must be held constant so they do not distort the result; these are the confounding factors.
Confounding variables that must be controlled, such as species, size, temperature, and time of day.
Topics that use Controlled variables
- Survival and response (A-level only) (AQA A-Level)
- Planning (OCR A-Level)
- Respiration (OCR A-Level)
Related terms
- Acetyl coenzyme A
- Active transport and maintenance of gradients
- Anabolic reactions and biosynthesis
- ATP as the universal energy currency
- ATP synthase
- Chi-squared (χ²) test
- Coenzymes
- Confounding factors
Using Controlled variables in the exam
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