BRAINCAKEEnzymes
Revision notes for Enzymes in Edexcel Biology (8BI0). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.
- EnzymesEnzymes are globular proteins that speed up the chemical reactions in living organisms.
- Extra-Cellular and Intracellular EnzymesEnzymes can be grouped by where they act.
- Biological CatalystsA catalyst is a substance that increases the rate of a chemical reaction without being used up.
- Lock and Key HypothesisThe lock and key hypothesis was proposed by Emil Fischer in 1894 to explain how enzymes work and why they are specific.
- Induced Fit HypothesisThe induced fit hypothesis was proposed by Daniel Koshland in 1958.
- Measuring Rate of ReactionThe rate of an enzyme-controlled reaction is the change in the amount of substrate or product per unit time.
- Effect of Substrate ConcentrationWhen enzyme concentration and all other conditions are kept constant, changing the substrate concentration gives a characteristic curve.
- Effect of TemperatureTemperature affects enzyme activity in two opposing ways.
- Effect of pHEach enzyme works fastest at a particular pH, its optimum pH.
- Effect of Enzyme ConcentrationIf the substrate concentration and all other conditions are kept constant, changing the enzyme concentration changes the number of active sites…
- Reversible and Irreversible InhibitionAn inhibitor is a substance that binds to an enzyme and reduces its activity.
- Competitive InhibitionA competitive inhibitor is a molecule with a similar shape to the substrate.
- Non-competitive InhibitionA non-competitive inhibitor does not bind to the active site.
- End-Product InhibitionEnd-product inhibition is a way that a cell controls a metabolic pathway: the final product of the pathway inhibits an enzyme that acts near the…