i dont understand this and have an exam coming up. someone help?
This is refering to enzymes and the way they work. When you have an enzyme, it works as a "lock" and you put the "key" in it. The "lock" is the active site in the enzyme. The "key" is the substrate. You then get an enzyme-substrate complex and then you get a product. If you know about enzymes, you should be fine getting your head around this. Hope this helps :)
The lock and key method (as opposed to the induced fit method) is where the enzyme's active site is a specific shape, of which it will only be able to form the enzyme-substrate complex with a specific substrate.
The Lock or The Enzyme has a specific active site (site of which reaction takes place) so only the Key or Substrate will only fit that "lock".
Try this page as well http://revisionworld.com/gcse-revision/biology/cell-activity/proteins-and-amino-acids/enzymes
Copyright © 2007 - 2023 Revision World Networks Ltd.