International A Level Biology / Cellular respiration
Core practical 15: a redox indicator and respiration in yeast revision notes
Edexcel International A Level Biology (YBI11), chapter 20: Cellular respiration, specification point 7.7. Part of the full course.
Watch the video lesson · International A Level Biology past papers
Methylene blue acts as an artificial hydrogen acceptor, so its colour change lets you time respiration in yeast. A controlled method and enzyme-based explanation help you interpret how temperature affects the rate.