Quiz
Enzyme Kinetics 1
Questions in this quiz (15)
1Which are true about Lineweaver-Burk plots?
- AThey are Vo vs. [S], gradient: Vmax/Km, y-intercept: 1/Km
- BThey are [S] vs. 1/Vo, gradient: Km/Vmax, y-intercept: 1/Km
- CThey are 1/[S] vs. 1/[Vo], gradient: Km/Vmax, y-intercept: 1/Vmax
- DThey are 1/Vo vs. 1/[S], gradient: 1/Vmax, y-intercept: Vmax/Km
2Which are true about Hanes-Woolf plots?
- AThey are Vo vs. [S], gradient: Km/Vmax, y-intercept: 1/Vmax
- BThey are [S] vs. [S]/Vo, gradient: 1/Vmax, y-intercept: Km/Vmax
- CThey are Vo vs. Vo/[S], gradient: Vmax, y-intercept: Km/Vmax
3For competitive inhibition, what happens to the kinetic parameters?
- AVmax increases, Km decreases
- BVmax decreases
- CKm decreases
- DKm increases
- EVmax decreases, Km increases
4What is Kcat and catalytic perfection
- AKcat is the time it takes for an enzyme to catalyse a reaction and catalytic perfection is defined by kcat
- BKcat is efficiency and catalytic efficiency is defined by Km/kcat
- CKcat is the number of reactions catalysed per active site per unit time and catalytic efficiency is defined by Km/kcat
- DKcat is the number of reactions catalysed per active site per unit time and catalytic efficiency is defined by kcat/Km
5If k2 >> k-1, then what does kcat/Km approximate to, and what is catalytic perfection limited to?
- AIt approximates to k1, and is limited by the rate of diffusion (10^8-10^9 M-1 s-1)
- BIt approximates to k2, and is limited by the flow rate (10^6)
- CIt approximates to k1, and is limited by the rate of diffusion (10^7)
- DIt approximates to k2, and is limited by the rate of diffusion (10^8-10^9 M-1 s-1)
6The Lineweaver-Burk plot evenly weights data and provides accurate estimates of kinetic parameters
- ATrue
- BFalse
7Low Km enzymes are highly efficient as they require less [S] to reach maximal reaction velocity.
- ATrue
- BFalse
8What is the Michaelis Menten equation and constant?
- AEquation: Vo = Km [S] / Vmax + [S]
- BEquation: Vo = Vmax [S] / Km + [S]
- CConstant: Km = k-1 + k2 / k1
- DConstant: k1 + k2 / k-1
9When [S] >> Km, Vo is dependent on [S]
- ATrue
- BFalse
10Which are true about uncompetitive inhibition?
- AThe inhibitor binds the ES complex but not free enzyme (E)
- BThe inhibitor does not bind the ES complex but binds the free enzyme (E)
- CVmax and Km both decrease by different amounts
- DVmax and Km both decrease by the same proportions
- EIncreasing [S], will increase the enzyme's susceptibility to inhibition
- FTo find Km and Vmax apparent, you must divide Km by alpha and divide Vmax by alpha
- GTo find Km and Vmax apparent, you must multiply Km by alpha and divide Vmax by alpha
- HThe inhibitor binds to the active site
- IThe inhibitor binds to another part of the enzyme
11Which are true about mixed inhibitors?
- AThey directly bind the active site
- BThey do not bind the active site
- CThey can bind either the substrate or enzyme
- DThey can bind either free enzyme or ES complexes
- EThey are only effective at high concentrations
- FThey are effective at both high and low concentrations
- GFor kinetic parameters you do Vmax/α' and αKm/α'
- HFor kinetic parameters you do Vmax/α and α'Km/α
12Which are true about non-competitive inhibitors?
- AThey bind to the active site
- BThey bind away from the active site
- CThey are a specific type of mixed inhibition where the affinity for E and ES is the same
- DThey are a specific type of uncompetitive inhibition where the Km and Vmax are the same
- EExtent of inhibition is independent of substrate concentration
- FExtent of inhibition is dependent on substrate concentration
- GExtent of inhibition is dependent on inhibitor concentration
- HVmax decreases (Vmax/α), Km increases (αKm)
- IVmax decreases (Vmax/α), Km is unchanged
- JVmax is unchanged, Km increases (αKm)
13Partial competitive inhibition is when the inhibitor partially inhibits the enzyme's ability to react with a substrate, decreasing the rate constant for the product-forming reaction.
- ATrue
- BFalse
14What are the x and y axes for partial inhibition graphs?
- A[I] vs. Ki
- BKi vs. [I]
- C[I] vs. Lineweaver-Burk gradient (Km/Vmax)
- D[I] vs. Hanes-Woolf gradient (1/Vmax)
- EKi vs. Lineweaver-Burk gradient (Km/Vmax)
15Partial non-competitive inhibitors modify the active site, but substrates may be able to overcome this and be catalysed, but they will be reacted with at a different rate to that of the ES complex. When you plot a graph, the β factor is an indication of the percentage of the enzyme that is active.
- ATrue
- BFalse
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- Degree Biochemistry (Enzyme Kinetics) Quiz on Enzyme Kinetics 1, created by Davina Jugnarain on 25/05/2016.
- Author
- Davina Jugnarain
- Language
- English
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