39 Questions
Which enzyme, glucokinase or hexokinase, has a lower Vmax?
Glucokinase
Which enzyme, glucokinase or hexokinase, has a lower Km?
Hexokinase
Which enzyme, glucokinase or hexokinase, is turned off by high concentrations of glucose-6-P?
Glucokinase
What same reaction do both hexokinase and glucokinase catalyze?
Conversion of glucose to glucose-6-P
Which enzyme, glucokinase or hexokinase, has a higher Km and is active even during fasting?
Glucokinase
Which enzyme, glucokinase or hexokinase, becomes active after a high-carbohydrate meal?
Hexokinase
What is the main role of the enzyme glucokinase?
Glycogenesis
Which enzyme is found in the liver?
Glucokinase
Why can't other tissues convert excess glucose to glycogen?
They lack the enzyme glucokinase
Which enzyme, glucokinase or hexokinase, is inhibited by glucose-6-P?
Hexokinase
Which type of enzyme inhibition occurs when the inhibitor forms a covalent bond with the active site of the enzyme?
Irreversible Enzyme Inhibition
Which type of enzyme inhibition competitively inhibits the enzyme that helps convert folate (B9) into its coenzyme form?
Reversible Enzyme Inhibition: Competitive
In reversible enzyme inhibition, which type of inhibition does not change the maximum velocity (Vmax) of the reaction?
Reversible Enzyme Inhibition: Competitive
In reversible enzyme inhibition, does the affinity of the enzyme appear to go up or down in the presence of the inhibitor?
The affinity of the enzyme appears to go down
Which type of enzyme inhibition results in no product formation even in the presence of substrate?
Reversible Enzyme Inhibition: Noncompetitive
In reversible enzyme inhibition, is the maximum velocity (Vmax) lower or higher in the presence of the inhibitor?
The maximum velocity (Vmax) is lower
In reversible enzyme inhibition, does the affinity of the enzyme appear to go up or down in the presence of the inhibitor?
The affinity of the enzyme appears to go down
Which type of enzyme inhibition occurs when the inhibitor binds to the enzyme or the enzyme-substrate complex?
Reversible Enzyme Inhibition: Noncompetitive
In reversible enzyme inhibition, does the maximum velocity (Vmax) change in the presence of the inhibitor?
The maximum velocity (Vmax) remains unchanged
In reversible enzyme inhibition, does the affinity of the enzyme appear to go up or down in the presence of the inhibitor?
The affinity of the enzyme remains unchanged
Which of the following defines Km and Vmax?
The concentration of substrate at which the enzyme is working at half of its maximum velocity and the maximum velocity of the reaction
Which of the following reactions conforms to Michaelis-Menten kinetics?
A zero order reaction
What is the difference between glucokinase and hexokinase?
Glucokinase has a higher Km value than hexokinase
What does Kcat represent?
The ratio of the catalytic rate constant to the dissociation constant of the enzyme-substrate complex
Which of the following is an example of a physiologically efficient enzyme and its role?
Glucokinase, which catalyzes the phosphorylation of glucose in the liver
How can we determine the Km and Vmax of an enzyme using Michaelis-Menten kinetics?
By measuring the initial reaction rate at different substrate concentrations and fitting the data to the Michaelis-Menten equation
What is the difference between reversible and irreversible enzyme inhibition?
Reversible inhibition can be overcome by increasing the substrate concentration, while irreversible inhibition cannot
What is the difference between competitive, uncompetitive, and non-competitive inhibition?
Competitive inhibition occurs when the inhibitor binds to the active site of the enzyme, uncompetitive inhibition occurs when the inhibitor binds to the enzyme-substrate complex, and non-competitive inhibition occurs when the inhibitor binds to a site other than the active site
How does the graph of an allosteric enzyme in the presence of an inhibitor differ from the graph in the absence of an inhibitor?
The graph in the presence of an inhibitor is shifted to the right, indicating a decrease in enzyme activity
Which of the following best defines Km in Michaelis-Menten kinetics?
The concentration of substrate at which the reaction rate is half of Vmax
Which of the following best describes a first-order reaction?
The reaction rate is directly proportional to the concentration of the substrate
Which of the following best describes a zero-order reaction?
The reaction rate is independent of the concentration of the substrate
What can we use a Lineweaver-Burk plot for?
To determine the Km and Vmax of an enzyme
Which of the following best defines Kcat?
The turnover number of the enzyme
Which of the following best describes reversible enzyme inhibition?
The inhibitor binds to the enzyme or the enzyme-substrate complex
Which of the following best describes irreversible enzyme inhibition?
The inhibitor permanently inactivates the enzyme
Which of the following best describes allosteric inhibition?
The inhibitor binds to a site other than the active site of the enzyme
Which of the following best describes competitive inhibition?
The inhibitor competes with the substrate for binding to the active site of the enzyme
Which of the following best describes uncompetitive inhibition?
The inhibitor binds to the enzyme or the enzyme-substrate complex
Test your knowledge on enzyme kinetics and regulation by comparing glucokinase and hexokinase. Explore differences in Vmax, Km, substrate specificity, and regulation in response to glucose concentrations.
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