MCGB - Enzyme Activity Flashcards
What is the name given to the high energy intermediate that lies between S and P in an enzyme reaction?
Transition state
What is the activation energy?
The minimum energy that substrates must have to start a reaction.
Why does increasing the temperature increase the rate of reaction?
Increases number of molecules with activation energy.
Why does increasing the concentration increase the rate of reaction?
Increases chance of molecular collisions.
What are enzymes?
Biological catalysts that increase the rate of reaction by lowering the activation energy required. This facilitates formation of the transition state.
Give an exception to the statement that all enzymes are proteins
Some RNA molecules act as enzymes.
Do enzymes affect the reaction equilibrium?
No
If the active site of an enzyme is only made of a few amino acids out of hundreds, what is the role of the rest of the enzyme?
A scaffold to create the active site
True or false - the active site is formed by amino acids from different parts of the primary sequence?
True
What sort of reaction takes place when the substrate molecule binds to the active site?
Condensation reaction
What is the difference between the lock-and-key and the induced fit model of enzyme action?
Lock and key states that the active site of the enzyme is already complementary to the shape of the substrate, while induced fit states that the active site only forms a complementary shape AFTER the binding of the enzyme.
True or false - substrates bind to enzymes by covalent bonds?
False - covalent is too tight. They must be multiple weak bonds.
What does V0 mean?
Initial rate of reaction.
What shape would a graph of reaction rate against substrate concentration be?
A rectangular hyperbola.
What does the Michaelis-Menten model suggest about enzyme catalysis?
A specific complex is a necessary intermediate, and that a plot of V0 vs [S] will be a rectangular hyperbola.