Chapter 7 Quiz
i and iv
A Lineweaver-Burk plot is also referred to as: Select all that apply i. a linear plot ii. a Michaelis-Menten plot iii. a sigmoidal plot iv. a double reciprocal plot
C
A graph of reaction velocity as a function of substrate concentration would yield a __________ curve for a Michaelis-Menten enzyme. A. sigmoidal B. linear C. hyperbolic
D
A new drug has been discovered which inhibits the reaction catalyzed by enzyme A. Based on the information shown, what is this drug? A. A noncompetitive inhibitor B. An uncompetitive inhibitor C. A mixed inhibitor D. A competitive inhibitor
B
A non-competitive inhibitor is added to an enzyme-catalyzed reaction that follows Michaelis-Menten kinetics. Which observation is correct? A. The inhibited Vmax is greater than the non-inhibited Vmax B. The inhibited Vmax is smaller than the non-inhibited Vmax C. The inhibited Vmax and non-inhibited Vmax are the same D. None of the answer choices are correct
1.68
An enzyme catalyzes a reaction with a Km of 7.00 mM and a Vmax of 2.55 mM∙s⁻¹. Calculate the reaction velocity, v₀, if the substrate concentration is 13.5 mM. Round your answer to 2 sig figs after the decimal
i, ii, and iii
Compounds that function as "mixed inhibitors": Select all that apply i. can bind to the enzyme/substrate complex ii. interfere with substrate binding to enzyme iii. bind to the enzyme reversibly iv. display parallel lines on the Lineweaver Burk plot
2.5
Determine the value of Ki for a competitive inhibitor whose data results in the linear equation y = 0.2188x + 0.02. The equation for the control line (no inhibitor) is y = 0.0632x + 0.0195. [I] = 5mM.
91208.79
Determine the value of the turnover number (kcat) for the enzyme carbonic anhydrase given that Vmax = 249 umol*L⁻¹*s⁻¹ and [E]tot = 2.73 nmol*L⁻¹. Round your answer to 2 sig figs after the decimal
i
In the simple enzyme-catalyzed reaction shown, which of the rate constants would be second-order? i. k₁ ii. k₂ iii. k₋₁
C
In uncompetitive inhibition: A. the inhibitor combines with EP B. the inhibitor combines with E and ES C. the inhibitor combines only with ES D. the inhibitor combines only with E
A
Km is defined as: A. the concentration of substrate where the enzyme achieves half Vmax B. as high if the enzyme has high affinity for the substrate C. a measure of the stability of the product D. half Vmax
False
T/F: Non-competitive inhibition can overcome by flooding the reaction with substrate.
B
The Km of hexokinase for glucose is 0.15mM and for fructose, Km = 1.5mM. Which is the preferred substrate? A. Neither substrate is preferred over the other B. Glucose C. Fructose
D
Use the plot provided to estimate the value of Vmax for the enzyme-catalyzed reaction. A. 20 uM B. 40 uM C. 10 uM D. 30 uM
A
Using the table shown, determine which enzyme can convert the most substrate to product in a given period of time.
B
Using the table shown, determine which enzyme has the highest affinity for substrate.
A
Using the table shown, determine which enzyme has the highest catalytic efficiency.
0.5
When [S] = Km, V₀ = (__________) x (Vmax)
ii and iv
Which of the following are true for inhibitor I if it is a competitive inhibitor? Select all that apply: i. The maximum velocity is lowered ii. At some point, S can displace all of the inhibitor on the enzyme iii. It binds a site other than the active site iv. It is structurally similar to the substrate
D
Which of the following statements regarding inhibitors is correct? A. The presence of a non-competitive inhibitor can be overcome by addition of more inhibitor B. A pure non-competitive inhibitor results in a higher Km C. A non-competitive inhibitor causes an increase in the Vmax D. A competitive inhibitor results in a higher Km
E
Which of the following would be a proper representation of enzyme velocity? A. v = -d[P]/dt B. v = d[P]/dt C. v = -d[S]/dt D. v = d[S]/dt E. Either B or C
C
_______________ enzyme inhibitors irreversibly bind the enzyme, inactivating it. A. Competitive B. Noncompetitive C. Suicide D. Uncompetitive E. Mixed
