BRAINCAKEEnzymes
Revision notes for Enzymes in OCR Biology A (H020). 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.
- The Role of EnzymesCell components need to be built and assembled from organic material.
- The Mechanism of Enzyme ActionEnzymes are soluble proteins that are dissolved in aqueous environments in the body.
- Lock and Key HypothesisThe previous model of enzyme action was that the substrate fits into the active site like a key fits in a lock.
- Induced-Fit HypothesisThe proximity of the substrate leads to a change in the shape of the enzyme which moulds itself around the substrate.
- Intracellular EnzymesAn intracellular enzyme is an enzyme that functions within the cell it was produced.
- Extracellular EnzymesCellular reactions require substrates.
- AmylaseAmylase is an enzyme that catalyses the digestion of starch to maltose.
- ProteasesProteins are broken down into amino-acids by digestion.
- Effect of Temperature on Enzyme ActivityAs the temperature is increased the kinetic energy of the molecules increases and the molecules move faster and collide more often and with more…
- Temperature ExtremesSome organisms (extremophiles) are able to survive in extremely cold or extremely hot environments.
- Effect of pH on Enzyme ActivityThe tertiary structure of the active site of the enzyme is determined by hydrogen and ionic bonds between -NH2 and -COOH groups and bonding and…
- Enzyme ConcentrationEnzymes are biological catalysts.
- Substrate ConcentrationAt low substrate concentration not all the active sites of the enzymes are filled as there are relatively few molecules of substrate.
- Competitive InhibitionInhibitors are substances that interfere with the function of enzymes either directly or indirectly.
- Non-competitive InhibitionNon-competitive inhibitors bind to a site which is not the active site.
- End-Product InhibitionEnd-product inhibition is used to control the level of the final product in a metabolic pathway.
- CofactorsCofactors are inorganic molecules that help enzymes carry out their functions as catalysts.
- CoenzymesCoenzymes are organic molecules that areneeded for the proper functioning of enzymes.
- Prosthetic GroupsProsthetic groups are non-protein cofactors that are permanently bound to proteins or enzymes and are needed for them to carry out their function.
- Precursor ActivationMany enzymes are produced as inactive precursors (called zymogens) so that they do not damage the cells producing them.