4.1 Enzyme Action Flashcards
What are enzymes?
Biological catalysts
Globular proteins that interact with substrate molecules causing them to react at faster rates
What are anabolic reactions?
Building up reactions
What are catabolic reactions?
Breaking down reactions
What is metabolism?
Sum of all the different reactions and reaction pathways in a cell or an organism
What is V max?
Maximum initial velocity or rate of the enzyme catalysed reaction
When does a successful reaction take place?
Molecules need to collide with correct orientation and sufficient energy
What is activation energy?
Energy required in order for a reaction to begin
What is the active site?
Area within the tertiary structure of the enzyme which has a complementary shape to the shape of a specific substrate molecule
Lock and key hypothesis
Only a specific substrate will fit the active site of the enzyme
How does an enzyme catalyse a reaction?
The substrate is held in a way that R groups within the active site of the enzyme interact with the substrate, forming temporary bonds
These put strain on the bonds within the substrate, which help the reaction along
Induced fit hypothesis
Active site of the enzyme changes shape slightly as the substrate enters
How does the induced fit work?
Initial interaction between enzyme and the substrate is quite weak, but these weak interactions rapidly cause changes in the enzyme’s tertiary structure, so the bond becomes stronger, putting strain on the substrate molecule. This can weaken bonds in the substrate, lowering activation energy for the reaction
Intracellular enzymes
Enzymes that act within cells
Catalase
Enzyme that makes sure hydrogen peroxide is broken down quickly into oxygen and water to prevent accumulation
Extracellular enzymes
Work outside the cell
