Worksheets1/28 Quiz
Total questions: 15
Worksheet time: 15mins
What do enzymes primarily do in biological systems?
Change the equilibrium constant of reactions
Lower the free energy of activation
Increase the free energy of reactions
Make unfavorable reactions favorable
In Michaelis-Menten kinetics, the steady-state assumption means:
Product concentration is constant
Substrate concentration is constant
ES formation rate equals ES breakdown rate
Enzyme concentration increases
A small Km indicates:
Weak substrate binding
Tight substrate binding
Low catalytic activity
Low enzyme concentration
Which statement best distinguishes ΔG from ΔG‡?
ΔG determines reaction rate
ΔG‡ determines equilibrium
ΔG‡ determines reaction rate
ΔG and ΔG‡ are interchangeable
Competitive inhibitors affect which parameters?
Increase Km only
Decrease Vmax only
Decrease both Km and Vmax
Do not affect either
In pure noncompetitive inhibition:
Km increases
Km decreases
Km is unchanged
Km becomes zero
Which inhibitor binds only to the ES complex?
Competitive
Noncompetitive
Mixed
Uncompetitive
Mixed noncompetitive inhibition differs from pure noncompetitive inhibition because:
Km is unchanged
Vmax is unchanged
Inhibitor has different affinities for E and ES
Inhibitor binds only ES
In a random sequential mechanism:
Substrates bind in a fixed order
Products are released before all substrates bind
Either substrate can bind first
No ternary complex forms
In a ping-pong mechanism, which event occurs first?
Binding of both substrates
Release of product P
Formation of ESB
Product Q release
What property of water allows it to dissolve ions effectively?
High viscosity
Nonpolarity
High dielectric constant
Low heat capacity
pH is defined as:
–log[H+]
–log[OH–]
log[H+]
log(Kw)
A large Ka value indicates:
A weak acid
A strong acid
A neutral compound
A buffer
If pH decreases, pOH will:
Decrease
Stay constant
Increase
Become zero
Why is histidine important in enzyme catalysis?
Strong acid
Strong base
Hydrophobic side chain
Imidazole side chain has near-neutral pKa
