Enzymes 1.4 Flashcards
What type of proteins are enzymes?
Globular proteins
How do enzymes speed up reactions?
Lowering the activation energy needed for a reaction to take place
What is the lock and key hypothesis?
Only one substrate will fit the shape of the active site, giving enzymes specificity
What is the induced-fit hypothesis?
The active site has a specific shape, but it is a flexible one. The shape of the active site is modified around the substrate
what calculation is used to calculate the affects of factors on the rate of reaction?
Initial rate of reaction
What is the initial rate of reaction?
When the reaction proceeds at its fastest rate
What happens to an enzyme if the temperature is too high?
-Enzyme denatures
-Shape of the active site changes
Why does an increase in temperature lead to higher rate of reaction?
Increases the number of successful collisions as molecules have more energy
What happens when substrate concentration is too high?
-Enzyme becomes saturated, all active sites are occupied by a substrate
-Rate of reaction won’t increase any further
What happens if enzyme concentration increases?
Rate of reaction will increase
What happens in competitive inhibition?
-Inhibitor molecule is similar shape to the substrate
-Competes for the active site
What happens in non-competitive inhibition?
-Inhibitor joins to the active site at the allosteric site
-Changes the shape of the active site
What happens in irreversible inhibition of enzymes?
-Inhibitor changes the shape of the active site permanently where it can’t be reversed
What are regulatory enzymes?
Enzymes that have a site separate to the active site where another molecule can bind bringing inhibition and regulating reactions
What is end-product inhibition?
A control system in which an enzyme at the beginning of a pathway is inhibited by one of the end products of the reactions
