28 Questions
What is the maximum rate of an enzyme-catalyzed reaction?
Vmax
What is the reason for the increase in reaction velocity with temperature?
Increased number of molecules with sufficient energy to pass over the energy barrier
What happens to the enzyme at temperatures above 40°C?
It is denatured
What is the optimal pH for most human enzymes?
Between 7.0 and 8.0
What is the reason for the decrease in enzyme activity at non-optimal pH values?
Change in the ionic state of the active site
What is the optimal pH for the enzyme pepsin?
1.2
What is the purpose of an enzyme in a biological reaction?
To catalyze the chemical reaction
What is the active site of an enzyme?
A region that fits the shape of the substrate
What is the enzyme-substrate complex?
A temporary combination of the enzyme and substrate
Which model of enzyme action proposes that the active site has a rigid shape?
Lock and Key Model
What is the role of cofactors in enzyme action?
To provide additional functionality to the enzyme
What is the difference between an apoenzyme and a holoenzyme?
Apoenzyme is the enzyme without its cofactor, while holoenzyme is the enzyme with its cofactor
What is the purpose of coenzymes in enzyme action?
To provide additional functionality to the enzyme
What is the role of activators in enzyme action?
To bind to the enzyme and increase its activity
What is the main purpose of the Michaelis-Menten kinetics model?
To relate reaction rates to the substrate concentration
What is the significance of a low Km value?
It indicates a strong binding between the enzyme and its substrate
What is the equation that describes the Michaelis-Menten kinetics model?
The equation is not provided in the text
What is the role of the enzyme-substrate complex (ES) in the Michaelis-Menten kinetics model?
It breaks down into products and free enzyme
What is the significance of the Michaelis constant (Km)?
It is a measure of the affinity of the enzyme for its substrate
Who developed the Michaelis-Menten kinetics model?
Michaelis and Menten
What is the relationship between the reaction rate and substrate concentration in the Michaelis-Menten kinetics model?
The reaction rate is directly proportional to the substrate concentration
What is the significance of a high Km value?
It indicates a weak binding between the enzyme and its substrate
What is the primary function of enzymes?
To act as a biological catalyst
Which part of the enzyme does the substrate molecule fit into?
Active site
What happens to the activation energy of a reaction when an enzyme is present?
It decreases
What kind of structure do most enzymes have?
Tertiary or quaternary
What is a cofactor in the context of enzymatic activity?
Additional non-protein molecules required for enzyme activity
What determines the specificity of an enzyme for its substrate?
The shape of the enzyme
Test your knowledge of enzymes, including their mechanisms of action, cofactors, classification, and factors affecting reaction velocity.
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