Enzymes Biology Quiz

What is the maximum rate of an enzyme-catalyzed reaction?

Vm
Velocity constant
Vmax (correct)
Saturation rate

What is the reason for the increase in reaction velocity with temperature?

Change in pH value
Denaturation of the enzyme
Decrease in substrate concentration
Increased number of molecules with sufficient energy to pass over the energy barrier (correct)

What happens to the enzyme at temperatures above 40°C?

It becomes less active
It is denatured (correct)
It is saturated
It becomes more active

What is the optimal pH for most human enzymes?

Between 7.0 and 8.0 (C) Signup and view all the answers

What is the reason for the decrease in enzyme activity at non-optimal pH values?

Change in the ionic state of the active site (A) Signup and view all the answers

What is the optimal pH for the enzyme pepsin?

1.2 (C) Signup and view all the answers

What is the purpose of an enzyme in a biological reaction?

To catalyze the chemical reaction (A) Signup and view all the answers

What is the active site of an enzyme?

A region that fits the shape of the substrate (A) Signup and view all the answers

What is the enzyme-substrate complex?

A temporary combination of the enzyme and substrate (D) Signup and view all the answers

Which model of enzyme action proposes that the active site has a rigid shape?

Lock and Key Model (D) Signup and view all the answers

What is the role of cofactors in enzyme action?

To provide additional functionality to the enzyme (A) Signup and view all the answers

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 (B) Signup and view all the answers

What is the purpose of coenzymes in enzyme action?

To provide additional functionality to the enzyme (A) Signup and view all the answers

What is the role of activators in enzyme action?

To bind to the enzyme and increase its activity (A) Signup and view all the answers

What is the main purpose of the Michaelis-Menten kinetics model?

To relate reaction rates to the substrate concentration (D) Signup and view all the answers

What is the significance of a low Km value?

It indicates a strong binding between the enzyme and its substrate (C) Signup and view all the answers

What is the equation that describes the Michaelis-Menten kinetics model?

The equation is not provided in the text (B) Signup and view all the answers

What is the role of the enzyme-substrate complex (ES) in the Michaelis-Menten kinetics model?

It breaks down into products and free enzyme (B) Signup and view all the answers

What is the significance of the Michaelis constant (Km)?

It is a measure of the affinity of the enzyme for its substrate (D) Signup and view all the answers

Who developed the Michaelis-Menten kinetics model?

Michaelis and Menten (D) Signup and view all the answers

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 (C) Signup and view all the answers

What is the significance of a high Km value?

It indicates a weak binding between the enzyme and its substrate (A) Signup and view all the answers

What is the primary function of enzymes?

To act as a biological catalyst (D) Signup and view all the answers

Which part of the enzyme does the substrate molecule fit into?

Active site (D) Signup and view all the answers

What happens to the activation energy of a reaction when an enzyme is present?

It decreases (D) Signup and view all the answers

What kind of structure do most enzymes have?

Tertiary or quaternary (B) Signup and view all the answers

What is a cofactor in the context of enzymatic activity?

Additional non-protein molecules required for enzyme activity (A) Signup and view all the answers

What determines the specificity of an enzyme for its substrate?

The shape of the enzyme (A) Signup and view all the answers