An updated IB Diploma Biology guide carries a first assessment 2028 label and a brand-new data booklet. Here's what's actually changed, what hasn't, and what to do about it.
Category: Practical Biology
IBDP Internal Assessment: Step-by-Step Guide to Measuring Transpiration in Plants
Transpiration is the loss of water vapour from plant leaves through stomata. The rate of transpiration is strongly affected by temperature, which influences both the evaporation of water from mesophyll cells and the aperture of stomata. In this investigation, you will use a potometer to measure water uptake as a proxy for transpiration rate across … Continue reading IBDP Internal Assessment: Step-by-Step Guide to Measuring Transpiration in Plants
IBDP IA: Effect of Substrate Concentration on Catalase Activity: Michaelis-Menten Kinetics
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.
IBDP IA Idea: Effect of Light Wavelength on Photosynthesis Rate: Constructing an Action Spectrum
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
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?
What is osmosis? Learn about water potential, partially permeable membranes and how osmosis works in living cells. IGCSE and IB biology revision guide.