Worksheets1st year bio.ch enzymes
Total questions: 28
Worksheet time: 14mins
Name
Class
Date
1.
What is the primary component of an enzyme's active site that binds the substrate?
a)
Amino acid residues
b)
Fatty acids
c)
Carbohydrate chains
d)
Nucleic acids
2.
What type of cofactor is a small organic molecule that helps in enzyme activity?
a)
Inorganic cofactor
b)
Coenzyme
c)
Metal ion
d)
Prosthetic group
3.
Which of the following is an example of an inorganic cofactor for enzymes?
a)
NADH
b)
Mg²⁺
c)
FADH₂
d)
Coenzyme A
4.
Which part of the enzyme’s active site is responsible for stabilizing the transition state?
a)
Substrate binding site
b)
Catalytic site
c)
Allosteric site
d)
Regulatory site
5.
What is the role of cofactors in enzyme function?
a)
Provide structural support
b)
Increase enzyme concentration
c)
Assist in enzyme catalysis
d)
Stabilize the enzyme structure
6.
What is the first step in the mechanism of enzyme action?
a)
Substrate binding
b)
Formation of the transition state
c)
Product release
d)
Enzyme denaturation
7.
What happens during the transition state in enzyme catalysis?
a)
Substrate is completely transformed into product
b)
Substrate binds to the enzyme at the active site
c)
The enzyme undergoes conformational change
d)
Product is released
8.
Which of the following is required to stabilize the transition state of an enzyme reaction?
a)
Water molecules
b)
Cofactors or coenzymes
c)
Substrate concentration
d)
Temperature
9.
What does the enzyme’s active site specifically interact with in the mechanism of enzyme action?
a)
The product
b)
The transition state
c)
The substrate
d)
The cofactor
10.
Which mechanism do enzymes primarily use to lower the activation energy of a reaction?
a)
Increase temperature
b)
Decrease substrate concentration
c)
Create a microenvironment that stabilizes the transition state
d)
Increase pH
11.
Which factor primarily influences the rate of enzyme-catalyzed reactions by affecting enzyme structure?
a)
pH
b)
Substrate concentration
c)
Temperature
d)
Salt concentration
12.
What happens to the rate of enzyme action when the substrate concentration increases, assuming enzyme concentration is constant?
a)
It decreases
b)
It remains the same
c)
It increases, then levels off
d)
It becomes unpredictable
13.
At very high temperatures, what typically happens to enzymes?
a)
Their activity increases
b)
They become denatured
c)
They bind more substrate
d)
They become more stable
14.
Which of the following statements is true about the effect of pH on enzyme action?
a)
Each enzyme has an optimal pH
b)
Enzyme activity is highest at any pH
c)
Enzymes are unaffected by pH
d)
pH only affects the substrate
15.
What does increasing enzyme concentration do to the rate of reaction, assuming constant substrate concentration?
a)
It decreases the rate
b)
It has no effect
c)
It increases the rate
d)
It causes enzyme inhibition
16.
Which factor decreases enzyme activity by disrupting the enzyme's 3D structure?
a)
Temperature increase
b)
Substrate concentration
c)
Enzyme concentration
d)
pH extremes
17.
How does the presence of inhibitors affect the rate of enzyme reactions?
a)
Increase the reaction rate
b)
Decrease the reaction rate
c)
No effect
d)
Activate the enzyme
18.
What effect does a cofactor have on an enzyme's activity?
a)
Increases substrate binding
b)
Decreases enzyme concentration
c)
Activates or enhances enzyme function
d)
Decreases enzyme specificity
19.
What type of inhibition occurs when the inhibitor binds to the enzyme's active site?
a)
Competitive inhibition
b)
Non-competitive inhibition
c)
Uncompetitive inhibition
d)
Allosteric inhibition
20.
In competitive inhibition, what happens to the enzyme's activity at high substrate concentrations?
a)
The inhibition is unaffected
b)
The inhibition increases
c)
The inhibition is relieved
d)
The enzyme becomes inactive
21.
Which of the following best describes non-competitive inhibition?
a)
The inhibitor competes with the substrate for the active site
b)
The inhibitor binds away from the active site, changing the enzyme's shape
c)
The inhibitor permanently inactivates the enzyme
d)
The enzyme-substrate complex is formed but the product is not produced
22.
What effect does uncompetitive inhibition have on the enzyme's Km and Vmax?
a)
Increases both Km and Vmax
b)
Decreases both Km and Vmax
c)
Increases Km, decreases Vmax
d)
Decreases Km, increases Vmax
23.
Which of the following inhibitors binds to the enzyme's allosteric site and changes the enzyme's conformation?
a)
Competitive inhibitor
b)
Non-competitive inhibitor
c)
Uncompetitive inhibitor
d)
Irreversible inhibitor
24.
Irreversible inhibitors typically form which type of bond with the enzyme?
a)
Covalent bond
b)
Hydrogen bond
c)
Ionic bond
d)
Van der Waals interactions
25.
Which of the following is an example of a reversible inhibitor?
a)
Cyanide
b)
Penicillin
c)
Sulfanilamide
d)
Organophosphates
26.
What is the primary function of feedback inhibition in metabolic pathways?
a)
To increase enzyme activity
b)
To regulate the pathway by inhibiting the first enzyme
c)
To enhance substrate binding
d)
To increase substrate concentration
27.
In feedback inhibition, what happens when the end product accumulates in the pathway?
a)
The pathway becomes more active
b)
The first enzyme in the pathway is inhibited
c)
The substrate concentration increases
d)
The product concentration decreases
28.
Feedback inhibition is an example of what kind of regulatory mechanism?
a)
Competitive inhibition
b)
Allosteric regulation
c)
Irreversible inhibition
d)
Genetic control
100 %
