What is the difference between competitive and non-competitive inhibition?

Competitive - this is when the inhibitor binds to the enzymes active site, this is due to the fact that the enzyme and inhibitor have the same complementary shape to the enzyme active site (meaning they can both potentially bind). A way too remember it is that they "compete with the enzyme for the active site".Non-Competitive- this is when the inhibitor binds to an allosteric site on the enzyme (somewhere that is not the active site), by doing so it changes the shape of the active site meaning the enzyme is no longer complementary to the active site preventing the formation of an enzyme-substrate complex.