Definition
A substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.
Most enzymes are proteins with large complex molecules whose action depends on their particular molecular shape. Some enzymes control reactions within cells and some, such as the enzymes involved in digestion, outside them
A substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.
Most enzymes are proteins with large complex molecules whose action depends on their particular molecular shape. Some enzymes control reactions within cells and some, such as the enzymes involved in digestion, outside them
Induced Fit
Although the Lock and Key model is essentially correct, things are a little different in practice. At least that is what we now believe. This modified model is called the Induced Fit Theory.
Activation Energy
Enzymes work in different ways, you don't need to worry about these at this level, but essentially they all work by reducing activation energy.
Consider a match. It has a certain amount of stored chemical energy. When we strike the match we are putting energy in. Once a reaction starts the energy is released as heat and light and the burnt match has less stored energy than the unlit match we started with.
Chemical reactions are the same. Chemicals try to get from being in a high energy state to a lower energy state. Often though, they need energy to get the process started. We call this the activation energy.
If the activation energy is high the reaction may never take place (as with a match that never gets struck). If we were to lower the activation energy then maybe the reaction would take place.
Enzymes lower the activation energy of biological reactions allowing them to happen more quickly and at the relatively low temperatures inside the body (especially in plants, fish and reptiles where temperatures are even lower).
You should be able to interpret graphs showing this.
Consider a match. It has a certain amount of stored chemical energy. When we strike the match we are putting energy in. Once a reaction starts the energy is released as heat and light and the burnt match has less stored energy than the unlit match we started with.
Chemical reactions are the same. Chemicals try to get from being in a high energy state to a lower energy state. Often though, they need energy to get the process started. We call this the activation energy.
If the activation energy is high the reaction may never take place (as with a match that never gets struck). If we were to lower the activation energy then maybe the reaction would take place.
Enzymes lower the activation energy of biological reactions allowing them to happen more quickly and at the relatively low temperatures inside the body (especially in plants, fish and reptiles where temperatures are even lower).
You should be able to interpret graphs showing this.