Practice Questions

Binding energy released during enzyme substrate interaction is primarily used to

A. Directly break substrate bonds
B. Increase activation energy
C. Lower activation energy by stabilizing the transition state
D. Dissociate the enzyme cofactor complex
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Jul 11, 2026

Activation of the catalytic serine hydroxyl group in serine proteases is achieved by

A. Bulk water
B. Histidine acting as a general base
C. Aspartate donating a proton
D. Formation of a disulfide bond
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Jul 11, 2026

In triose phosphate isomerase, glutamate abstracts a proton from the substrate. It acts as a

A. General acid
B. Lewis acid
C. General base
D. Metal ion cofactor
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Jul 11, 2026

Catalysis by approximation is achieved by

A. Denaturing the substrate
B. Binding two substrates close together to increase their effective concentration
C. Lowering the pH of the solution
D. Using a metal ion to generate hydroxyl radicals
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Jul 11, 2026

The catalytic efficiency of an enzyme is best described by the ratio

A. Kcat / Vmax
B. Km / Kcat
C. Kcat / Km
D. Vmax / Kcat
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Jul 11, 2026

During the mechanism of chymotrypsin, the “pong” step involves

A. Release of the unaltered second substrate
B. Binding of a water molecule and its nucleophilic attack on the acyl enzyme intermediate
C. Binding of an allosteric inhibitor
D. Auto degradation of the enzyme
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Jul 11, 2026

Formation of a covalent enzyme substrate intermediate after the first product leaves is characteristic of

A. Sequential ordered mechanism
B. Sequential random mechanism
C. Ping pong double displacement mechanism
D. Concerted acid base mechanism
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Jul 11, 2026

A ping pong mechanism refers to a kinetic sequence where

A. Substrate inhibits product
B. One product is released before all substrates bind
C. Cooperative binding occurs
D. Non competitive inhibition occurs
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Jul 11, 2026

In lysozyme, Glu35 remains protonated because its microenvironment is

A. Highly hydrophilic
B. Hydrophobic and non polar
C. Rich in lysine residues
D. Completely neutral
nmdcat.online BIO NMDCAT
Jul 11, 2026

The x intercept of a Lineweaver Burk plot equals

A. -1/Vmax
B. -1/Km
C. Vmax/Km
D. Km/Vmax
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Jul 11, 2026
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