Catalase is one of the most efficient enzymes known, breaking down hydrogen peroxide into water and oxygen at rates of up to 40 million reactions per second. In this investigation, you will measure how the rate of catalase activity changes as substrate concentration increases, generating a Michaelis-Menten curve and allowing calculation of the maximum reaction velocity (Vₘₐˣ) and the Michaelis constant (Kₘ). This is a fully quantitative IB Biology HL Internal Assessment investigation.
This practical is suitable for IB Diploma Biology HL and Edexcel IGCSE Biology.
Different wavelengths of light are absorbed differently by photosynthetic pigments. By measuring the rate of photosynthesis in Elodea (Canadian pondweed) under light of different wavelengths, you can construct an action spectrum — a graph showing photosynthetic rate against wavelength — and compare it to the known absorption spectra of chlorophyll a, chlorophyll b, and carotenoids. This is an elegant and visually striking IB Biology IA.
IB Biology IA: Beetroot and Cell Membrane Permeability
In this investigation, you will use beetroot tissue to explore how increasing temperature affects the permeability of cell membranes. As membranes are damaged by heat, the red pigment anthocyanin leaks out of the vacuole — the more pigment released, the more permeable the membrane has become. A colorimeter is used to measure absorbance quantitatively, making this an excellent IB Biology IA investigation.
This practical is suitable for IB Diploma Biology and Edexcel IGCSE Biology students.
What is osmosis? Learn about water potential, partially permeable membranes and how osmosis works in living cells. IGCSE and IB biology revision guide.
Free IGCSE Biology Quizlet flashcard links for every topic. Interactive revision with flashcards, quizzes and games for Edexcel IGCSE Biology students.
