What are biochemical reactions collectively called?
metabolism
Describe the structure of an enzymes
Enzymes are globular proteins with a specific tertiary structure, held by hydrogen bonds, ionic bonds, disulphide bridges and hydrophobic ineractions
What is the function of enzymes?
They act as biological catalysts meaning they speed up the rate of metabolic reactions by lowering the activation energy
Where can enzymes work?
Inside cells (intracellular) and outside our cells (extracellular)
What are the 2 types of reactions which enzymes catalyse?
Anabolic reactions
Catabolic reactions
What is the function of anabolic reactions? Give an example
Building complex molecules
e.g. Photosynthesis
What is the function of catabolic reactions? Give an example
Breaking down complex molecules
e.g. Respiration
What are the 2 main models for enzymes action?
Lock and Key Model
Induced fit Model
Describe enzyme action in the Lock and Key Model
-The substrate molecule fits into the active site of the enzyme molecule like a key fitting into a lock; they are complementary shapes
-This forms the enzyme-substrate complex
-The product is then formed and as it no long fits in the active site it is released
Describe enzymes action in the Induced Fit Model
-The substrate and the active site of the enzyme are not complementary shapes
-When a substrate molecule binds to the active site the active site changes shape and fits itself around the substrate
-This places a strain on the substrate molecule and distorts a particular bond lowering the activation energy required to break the bond
-The products are formed and leave the active site which then returns to its original shape
State 3 properties of enzymes
-Specific due to complementary shape (This depends on the sequence of amino acids that make up the active site)
-Fast acting with a very high turnover number.This means that they can convert many molecules of substrate per unit time
-Soluble with hydrophilic R group found on the outside of the molecule
