enzymes 1.4 Flashcards
What are enzymes?
Biological catalysts that speed of the rate of reactions whilst remaining unchanged
What is the structure of enzymes?
Globular protein (tertiary proteins held together by hydrogen bonds, ionic bonds, and disulphide bridges)
What is the function of intracellular enzymes?
DNA replication
What is the function of extracellular enzymes?
Digestion
What are the two models of enzyme action?
-Lock and key model
-Induced fit model
What are the features of the lock and key model?
-Fully complimentary
-Active site unchanged
-Bonds are weak
What are the features of the induced fit model?
-Not fully complimentary
-Active site changes shape
-Stronger bonds
What happens to enzymes at low temperature?
-enzyme and substrate have less KE so move slowly
-Fewer successful collisions
-Fewer enzyme-substrate complexes formed
-rate of reaction is low
What happens to enzymes at optimum temperature?
-Maxing maximum number of enzyme-substrate complexes per unit of time
What happens to enzymes above optimum temperature?
-Heat breaks Hydrogen bonds
-Shape of active site changes
-Fewer ES complexes formed
-Rate is reduced and enzymes denatured
What happens to enzymes above/below optimum pH?
-Ionic bonds break
-Shape of active site changes
-Fewer ES complexes
-Rate reduced
What are the key points of competitive inhibition?
-Shape of inhibitor is similar to substrate
-Inhibitor binds with active site
-Inhibitor will move out of active site
What are the key points of non-competitive inhibition?
-Inhibitor is different shape from substrate
-Inhibitor binds with allosteric site
-Shape of active site changes
What are immobilised enzymes?
-Enzymes that have been trapped in an inert matrix
What are the advantages of immobilised enzymes?
-Multi use of enzymes
-Stop reaction rapidly
-Product not contaminated
-Bigger pH/temp range
