3.2.1 Enzyme

Active Site

place where substances come to react

Enzyme

protein that is a biological catalyst

Substrate

reactant in a chemical reaction upon which an enzyme acts

Catabolic reaction

releases energy/ breaks bonds

Catalyst

substance that decreases the activation needed to start a reaction

How do catalysts work?

All catalysts work by lowering the activation energy for a reaction. This is the minimum quantity of energy that reactants must possess to undergo a specific reaction.

What do cofactors do?

Cofactors are chemicals that assist enzymes during the catalysis of reactions by allowing the active site to change into the correct shape for the substrate. Enzymes are useless unless the coenzyme is present.

What is competitive inhibition?

Competitive inhibitors function by binding reversibly to the active site of the enzyme and competing for the site with substrate, therefore lowering the rate of reaction.

Induced fit model

Induced Fit. When an enzyme binds to the appropriate substrate, subtle changes in the active site occur. This alteration of the active site is known as an induced fit. Induced fit enhances catalysis, as the enzyme converts substrate to product.

what is non competitive inhibition?

Non-competitive inhibition uses a chemical that binds away from the active site but causes a chemical change in the enzyme which prevents substrate from binding.

Lock and Key Model

One model of enzyme function where the substrate perfectly fits into the active site without changing.

Denatured

Protein that has changed in structure making it less effective at its job by changing the temperature or pH

Anabolic reaction

Stores energy/ builds bonds

What is an active site?

The specific location on the enzyme where the substrate binds to undergo a chemical reaction

What is a catalyst?

a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change. It is reusable.