enzymes Flashcards
what do enzymes do
speed up reactions by acting as a biological catalyst
what do enzymes catalyse
metabolic reactions
are enzymes proteins yes or noe
yes
what do enzymes have
they have an active site which has a specific shape
what is an active site
part of an enzyme where the substrate molecules bind to forming and enzyme-substrate complex
why are enzymes highly specific
because of their tertiary structure
what is the activation energy
the certain amount of energy that needs to be supplied to the chemicals before the reaction will start
what can enzymes do to the activation energy
they can lower it and make reactions happen at a lower temperature which speeds up the rate of reaction
what is it called when a substrate fits into an enzymes active site
enzyme-substrate complex
why does an enzyme-substrate complex lower the activation energy (give two reasons)
if two substrate molecules need to be joined, being attached to the enzyme holds them close together, reducing any repulsion between the molecules so they can bond more easily
If the enzyme catalysing a breakdown reaction , fitting into the active site puts strain on bonds in the substrate so the substrate molecule breaks up more easily
what was the old model about enzymes fitting with their specific substrate
the lock and key model
what is the new model about enzymes fitting with their specific substrate
the induced fit model
explain the induced fit model
the substrate has to change the enzymes active site when it bind to the enzyme (think of it like a glove) the products are released and the active site will not go back to normal
how many reactions can one enzyme catalyse
one
why do enzymes only catalyse one reaction
only one complementary substrate will fit into the active site
how can the shape of an enzyme be changed
changes in pH or temperature
