30 Questions
Which enzyme is active even during fasting?
Hexokinase
Which enzyme needs lots of glucose to be activated?
Glucokinase
What is the main role of glucokinase and hexokinase?
Both Glycolysis and Glycogenesis
What pathway does hexokinase feed into if it can't do glycogenesis?
Glycolysis
What does a low Km value indicate for an enzyme?
High affinity
Why is hexokinase inhibited by glucose-6-P, but glucokinase is not?
Glucokinase has a lower Km
What is the general purpose of very efficient enzymes?
Catalyzing important physiological reactions
What are some applications of enzyme inhibition?
Modulating enzyme activity
What type of reversible enzyme inhibition is characterized by binding of the inhibitor to the active site of the enzyme?
Competitive inhibition
What does competitive inhibition do to the affinity of the enzyme for its substrate?
Decreases affinity
Which type of reversible enzyme inhibition involves binding of the inhibitor to the enzyme-substrate complex (ES)?
Uncompetitive inhibition
In uncompetitive inhibition, is the maximum reaction rate (Vmax) lower or higher in the presence of the inhibitor?
Lower
Does the affinity of the enzyme appear to go up or down in the presence of an uncompetitive inhibitor?
Up
Which type of reversible enzyme inhibition involves binding of the inhibitor to either the enzyme or the enzyme-substrate complex (ES)?
Noncompetitive inhibition
In noncompetitive inhibition, is the maximum reaction rate (Vmax) lower or higher in the presence of the inhibitor?
Lower
In noncompetitive inhibition, does the affinity of the enzyme appear to go up or down in the presence of the inhibitor?
Down
Which type of reversible enzyme inhibition involves binding of the inhibitor to the enzyme but not at the active site?
Mixed inhibition
In mixed inhibition, is the maximum reaction rate (Vmax) lower or higher in the presence of the inhibitor?
Lower
In mixed inhibition, does the affinity of the enzyme appear to go up or down in the presence of the inhibitor?
Down
Which type of enzyme inhibition occurs when an inhibitor forms a covalent bond with the active site of the enzyme?
Irreversible inhibition
Which of the following best describes a first-order reaction?
The rate of the reaction is directly proportional to the concentration of the reactant.
What is the key difference between glucokinase and hexokinase?
Hexokinase has a lower Vmax and a lower Km compared to glucokinase.
What is the purpose of a Lineweaver-Burk plot?
To determine the Km and Vmax of an enzyme.
Which of the following best describes a zero-order reaction?
The rate of the reaction remains constant regardless of the concentration of the reactant.
What is the definition of Km in Michaelis-Menten kinetics?
The concentration of substrate at half of the maximum velocity.
What is the definition of Vmax in Michaelis-Menten kinetics?
The maximum velocity of the reaction.
Which of the following best describes reversible inhibition?
The inhibitor binds reversibly to the enzyme.
Which of the following best describes irreversible inhibition?
The inhibitor binds irreversibly to the enzyme.
Which of the following best describes competitive inhibition?
The inhibitor binds to a different site on the enzyme.
Which of the following best describes non-competitive inhibition?
The inhibitor does not affect the activity of the enzyme.
Test your knowledge on enzyme kinetics with this quiz. Learn about Km, Vmax, first-order, pseudo-first order, and zero-order reactions. Challenge yourself and see how much you know about enzymes and their kinetics.
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