Enzymes - what are they, what is their purpose? Flashcards
Define: substrate, active site, enzyme-substrate complex.
Substrate: The reactant that an enzyme acts on.
Active Site: The region on the enzyme where the substrate binds.
Enzyme-Substrate Complex: The temporary complex formed when an enzyme binds to its substrate.
Describe the induced-fit model.
Enzymes are flexible and change shape to fit the substrate better.
What is activation energy (Ea)? How does it change when enzymes are involved?
Activation Energy: The energy needed to start a reaction.
With Enzymes: Enzymes lower the activation energy, speeding up the reaction.
Define cofactor and coenzyme
Cofactor: A non-protein component (often a metal ion) essential for enzyme activity.
Coenzyme: An organic molecule that acts as a cofactor (e.g., NAD+).
How does the concentration of an enzyme affect the rate of a catalysis reaction?
Enzyme Concentration: More enzyme increases the reaction rate until the substrate is the limiting factor.
How does the concentration of a substrate affect the rate of a catalysis reaction?
Substrate Concentration: More substrate increases the reaction rate until the enzyme is saturated.
How does the pH and temperature affect the rate of a catalysis reaction?
Temperature: Increases reaction rate up to an optimal point, after which enzymes denature.
pH: Each enzyme has an optimal pH. Deviations can lead to decreased activity and denaturation.
Describe feedback inhibition
Excess product inhibits enzyme activity to prevent resource waste.
What is the difference between competitive and noncompetitive inhibition?
Competitive Inhibition: The inhibitor competes with the substrate for the active site.
Noncompetitive Inhibition: Inhibitor binds elsewhere on the enzyme, changing its shape and function.
Enzyme
Enzymes are proteins that act as biological catalysts, speeding up chemical reactions in the body to support vital processes like digestion and metabolism.
