Enzyme Flashcards
What are enzymes?
Enzymes are globular protein molecules that speed up or catalyze specific chemical reactions in cells.
What part of an enzyme binds to the substrate?
The active site is the region of the enzyme where the substrate binds.
What does enzyme specificity mean?
Enzymes are specific to their substrates due to the complementary shape of the active site.
How do the “Lock and Key” and “Induced Fit” models differ?
• Lock and Key Model: The enzyme’s active site and substrate fit exactly.
• Induced Fit Model: The enzyme’s shape slightly changes to accommodate the substrate.
How do enzymes increase reaction rates?
Enzymes lower the activation energy required for a reaction, making it occur faster.
What is a metabolic pathway?
A sequence of enzyme-catalyzed reactions where each step is facilitated by a specific enzyme.
What are the key factors that affect enzyme activity?
- Temperature
- pH
- Substrate concentration
- Enzyme concentration
- Presence of inhibitors
What happens to enzyme activity at different temperatures?
• Low temperatures: Slow enzyme activity due to fewer collisions.
• Optimum temperature (e.g., 37°C in humans): Maximum activity.
• High temperatures: Enzyme denatures, losing function.
How does pH affect enzyme activity?
• Enzymes work best at an optimum pH.
• Deviations from the optimum pH cause denaturation, preventing substrate binding.
How does substrate concentration affect enzyme activity?
• Low concentration: Fewer collisions → slower reaction.
• Increasing concentration: Faster reaction.
• Saturation point: Enzyme active sites are full, so reaction rate plateaus.
How does enzyme concentration affect the reaction rate?
• More enzyme molecules → faster reaction (if substrate is available).
• Limited substrate → adding more enzyme has no effect.
What are enzyme inhibitors?
Molecules that decrease enzyme activity by interfering with substrate binding.
What is the difference between competitive and non-competitive inhibitors?
• Competitive inhibitors: Mimic the substrate and bind to the active site.
• Non-competitive inhibitors: Bind elsewhere on the enzyme, changing its shape.
How does end-product inhibition regulate enzymes?
The final product of a metabolic pathway binds to an enzyme, reducing its activity and preventing overproduction.
How are enzyme inhibitors used in agriculture?
Herbicides like glyphosate inhibit plant enzymes, preventing growth and killing weeds.
What separates those who succeed from those who merely wish?
“The difference between ordinary and extraordinary is that little extra.” - Jimmy Johnson
