University of Central Florida FIL 1000 CH 6 Quiz 1)A noncompetitive inhibitor Select one: a

University of Central Florida

FIL 1000

CH 6 Quiz

1)A noncompetitive inhibitor Select one:

a.            binds to the enzyme at a site other than the active site

b.            is structurally related to the substrate

c.             does not affect the value of Vmax

d.            decreases the value of KM

2. A rate constant is Select one:

a.            the rate of a reaction at standard temperature and pressure.

b.            the rate of a reaction at equilibrium.

c.             a proportionality constant relating the rate of a reaction to the concentration(s) of the reactant(s).

d.            a kind of transition state.

3. Non-competitive inhibitors have this effect:

Select one:

a.            Modifying the KM value.

b.            Changing the value for Vmax.

c.             Interfering with substrate binding.

d.            This type of inhibitor both changes the Vmax and interferes with substrate binding.

e.            All of these are correct.

4. The active site of an enzyme Select one:

a.            is frequently located in a cleft in the enzyme.

b.            is the portion of the enzyme to which the substrate binds.

c.             contains the reactive groups that catalyze the reaction. d. all of these are correct

5. The initial rate of an enzymatic reaction is usually determined in order to assure that Select one:

a.            the enzyme is active

b.            there is no reverse reaction of product to the enzyme-substrate complex

c.             the substrate is not used up

d.            the experiment can be completed quickly

6. The value of Vmax changes in Select one:

a.            competitive inhibition

b.            noncompetitive inhibition

c.             both forms of inhibition

d.            neither form of inhibition

7. What effect does a catalyst have on the ΔG° of a reaction? Select one:

a.            A catalyst lowers the ΔG°.

b.            A catalyst raises the ΔG°.

c.             A catalyst has no effect on the ΔG°.

d.            It depend on the specific catalyst.

8. Enzymatic activity has an optimum temperature because Select one:

a.            the component amino acids have varying melting points

b.            the rate of reactions is thermodynamically controlled

c.             the side chains of essential residues are chemically degraded at higher temperatures d. raising the temperature speeds up the reaction until protein denaturation sets in

e. the organism dies beyond a certain temperature

9. Irreversible inhibitors of enzymatic reactions Select one:

a.            bind to the enzyme only at low temperatures.

b.            affect only serine side chains.

c.             react with the enzyme to produce a protein that is not enzymatically active and from which the original enzyme cannot be regenerated.

d.            are bound to the enzyme by the lock-and-key mechanism.

10. The main difference between a catalyzed and an uncatalyzed reaction is that Select one:

a.            the activation energy of the catalyzed reaction is lower.

b.            the catalyzed reaction has a more favorable free energy change.

c.             the catalyzed reaction has a more favorable enthalpy change.

d.            the catalyzed reaction has a more favorable entropy change.