Enzymes Flashcards
What is an enzyme
A biological catalyst- they are necessary to speed up the reactions needed for life to exist. Without them, these reactions would be too slow to sustain life.
What is the active site
The part of the enzyme where the reaction occurs and the substrate binds to.
What is the substrate
The molecule the enzyme acts upon
What is the lock and key hypothesis
It is how the enzyme and substrate fit together in order to work. The substrate will bind to the enzyme to create the enzyme-substrate complex. Once the reaction is done, the enzyme becomes free to act on another substrate. If the shape changes/no longer fits then the reaction will slow.
What is meant by denaturing
when the active site changes shape so the substrate cannot bind to the enzyme. This change of shape is often irreversible. Once all enzymes have been denatured the reaction will stop.
Why can’t an enzyme work for multiple types of molecule
Enzymes are specific e.g. carbohydrase works for carbohydrates but not proteins
What factors affect enzymes
pH, temperature, enzyme and substrate concentration
How does pH affect enzymes?
All enzymes have an optimum pH, which is the pH they work best at. If the pH strays too far from the optimum, then the enzyme will denature
How does temperature affect enzymes?
The higher the temperature, the higher the rate of reaction, due to increased kinetic energy. If the temperature is too high, the enzyme will denature.
How does concentration affect enzymes
The higher the concentration of the substrate, the higher the rate of reaction, but if it no new enzyme molecules are added the reaction will slow and stop. The same is true with enzyme concentration. The higher the concentration of the enzyme, the higher the rate of reaction, but if it no new substrate molecules are added, no new enzyme molecules added will affect the rate of reaction (plateau)
