2.4 Enzymes Flashcards
What are enzymes?
Enzymes are globular proteins that biologically catalyse or speed up reactions.
How do enzymes speed up reactions?
By lowering the activation energy.
What is the area of the enzyme that has a complementary shape to the substrate and binds to it?
Active Site
What are the two hypothesis models of enzymes binding to substrates?
Lock and Key hypothesis
Induced Fit hypothesis
Describe the lock and key hypothesis.
Where the active site of the enzyme has a perfectly complementary shape to the substrate and fits completely.
Describe the induced fit hypothesis.
Where the enzymes change shape and close around the substrate to have a complementary shape.
What are enzyme inhibitors?
Inhibitors are substances that interfere with enzymes. They can be reversible or irreversible.
What are competitive inhibitors?
Inhibitors that bind to the active site of the enzyme and prevent substrates from binding to them.
What are non-competitive inhibitors?
Inhibitors that bind to the allosteric site of the enzyme and changes the shape of the enzyme. This prevents the enzyme from binding to the substrate as they no longer have a complementary shape.
What is the temperature coefficient (Q10)?
The change in a rate of reaction when a temperature is increased by 10 degrees.
What is a cofactor?
A non protein that is added to some enzymes to catalyse a reaction.
What are the two types of cofactor?
Prosthetic Groups and Coenzymes.
What is a prosthetic group?
Inorganic groups that are permanently bound to the enzyme/
What is a coenzyme?
An organic group that is changed by the enzyme after binding to it and then recycled.
Name 3 factors that affect the rates of enzyme controlled reactions.
Temperature
Substrate Concentration
Enzyme Concentration
