Enzymes Flashcards
what are enzymes
proteins that act as biological catalysts to speed up chemical reactions in living organisms.
what does every enzyme have
an active site with a unique shape that fits onto the substance involved in a reaction
what happens if the substrate does not match the enzymes active site
the reaction won’t be catalysed
what is a catalyst
a substance that speeds up a chemical reaction without being consumed or chemically changed during the reaction
what is the diagram to represent an enzyme
lock and key model. this is simpler than how the enzymes actually work
In reality, the active site changes shape a little as the substrate binds to it to get a tighter fit. this is called the ‘induced fit’ model of enzyme action
what happens when the temperature changes in an enzyme-catalysed reaction
it changes the rate
what if the reaction gets to hot
some of the bonds holding the enzyme together break.
this changes the shape of the enzymes active site, so the substrate will not fit anymore
what is normally the optimum pH for enzymes
often neutral pH 7, but not always - pepsin is an enzyme used to break down proteins in the stomach, it works best at 2, meaning it is well suited to the acidic conditions
why do enzymes have an optimum pH
if the pH is too high or low, it can interfere with the bonds holding the enzyme together. this changes the shape of the active site.
