KA1- Activation energy Flashcards
What is activation energy?
The energy needed to break chemical bonds in reactant chemicals
When do these bonds break?
When the molecules of the reactants have absorbed enough energy to make them unstable and they enter a transition state when the reaction can occur
What is a catalyst?
A substance which:
lowers the activation energy needed for a chemical reaction
Speeds up the rate of chemical reactions
Remains chemically unchanged at the end
What is an enzyme?
A biological catalyst that’s made of a protein
What shape are enzymes?
They are globular protein molecules with an active site which is a specific shape
What are the active sites of an enzyme a specific shape?
Due to the structure and bonding of the amino acids in the polypeptide chain
What does an enzyme only act on?
One substrate which has a complementary shape to the active site
What does induced fit reduce?
The activation energy needed for the reaction to occur
What is the active site of an enzyme made of?
Protein
What happens when the molecule of a substrate enters the active site?
The shape of the enzyme molecule changes slightly, making the active site fit very closely round the substrate molecule
What is induced fit?
When the molecule of a substrate enters the active site and the shape of the enzyme molecule changes slightly, making the active site fit very closely round the substrate molecule
Why do molecules of the substrate have a high affinity to the enzyme’s active site?
Induced fit
What happens to the products?
They have a different shape and don’t fit the active site, so they have a low affinity to the active site and are released, leaving the enzyme free to repeat this process with new substrate molecules
When the reaction involves 2+ sun stares the shape of the active site determines what?
The orientation. Of the reactants
What are the 4 factors which affect enzyme action?
Temperature
pH
Substrate concentration
Enzyme concentration
