1.7, 1.8 and 1.9 - Enzymes: Mechanisms, Denaturation and Factors Affecting Enzyme Activity Flashcards
What are enzymes?
Enzymes are biological catalysts that increase the rate of reaction without being used up.
What role do enzymes play in reactions?
Enzymes are present in many reactions, allowing them to be controlled.
What can enzymes do to molecules?
Enzymes can both break up large molecules and join small ones.
What are enzymes made of?
Enzymes are protein molecules, and the shape of the enzyme is vital to its function.
What is an active site?
Each enzyme has its own uniquely shaped active site where the substrate binds.
What is the Lock and Key Hypothesis?
The Lock and Key Hypothesis is a simplified explanation of how enzymes work.
How does the Lock and Key Hypothesis describe enzyme action?
The shape of the substrate is complementary to the shape of the active site, forming an enzyme-substrate complex.
What happens after the substrate binds to the enzyme?
Once bound, the reaction takes place and the products are released from the surface of the enzyme.
What is enzyme specificity?
Enzymes can only catalyse reactions when they bind to a substrate that has a complementary shape.
What conditions do enzymes require to function optimally?
Enzymes require an optimum pH, temperature, and substrate concentration.
What is the optimum temperature range for humans?
The optimum temperature in humans is around 37 degrees Celsius.
How does temperature affect the rate of reaction in enzymes?
The rate of reaction increases with an increase in temperature up to the optimum, but above this temperature, it rapidly decreases and eventually stops.
What happens to enzymes when the temperature becomes too hot?
The bonds that hold the enzyme together begin to break, changing the shape of the active site.
What does it mean when an enzyme is denatured?
The enzyme can no longer work because the substrate can no longer fit into the active site.
What is the optimum pH for most enzymes?
The optimum pH for most enzymes is 7 (neutral).
Do some enzymes have a different optimum pH?
Yes, some enzymes produced in acidic conditions, such as those in the stomach, have a lower optimum pH.
How does pH affect enzyme activity?
If the pH is too high or too low, the forces holding the amino acid chains will be affected, changing the shape of the active site.
What occurs when the shape of the active site changes?
The substrate can no longer fit in, and the enzyme is said to be denatured.
What happens to the rate of reaction as substrate concentration increases?
The rate of reaction will increase up to a point as substrate concentration increases.
What is the saturation point in enzyme activity?
The saturation point is the point at which increasing substrate concentration has no effect on the rate of reaction.
Is the saturation point the same for all enzymes?
No, the saturation point is different for every enzyme.
