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Essential Biochemistry - Enzymes (Section 2)

1
How does an enzyme affect the energy profile of a reaction?
Answer
(A)
It lowers the activation energy.
2
Which of the following non-proteins can act in an enzyme?
Answer
(B)
RNA
3
The active site of an enzyme is the region that:
Answer
(A)
Binds to the substrate.
4
Which enzyme is useful in the treatment of gastric ulcers?
Answer
(C)
Renin
5
Enzymes are biological catalysts that:
Answer
(A)
Increase the rate of reactions
6
What is the function of a kinase?
Answer
(A)
Transferring a phosphate group
7
Which factors influence enzyme activity?
Answer
A
B
C
D
8
Which of the following is an example of a non-protein component that is essential for enzyme function?
Answer
(C)
A cofactor
9
The substrate concentration at which an enzyme inhibitor has half the maximum velocity is known as:
Answer
(C)
Km
10
In which type of inhibition does the inhibitor bind only to the enzyme-substrate complex?
Answer
(C)
Uncompetitive inhibition
11
What type of inhibitor can be overcome by increasing the substrate concentration?
Answer
(C)
Competitive inhibitor
12
What is the effect of a competitive inhibitor on the Vmax of an enzyme-catalyzed reaction?
Answer
(C)
Vmax remains unchanged.
13
Which class of inhibitors involves the formation of a covalent bond with the enzyme, leading to irreversible inactivation?
Answer
(D)
Irreversible
14
Which enzyme is specifically used in the diagnosis of myocardial infarction?
Answer
(B)
CK-MB
15
Which of the following types of enzyme inhibitors usually bind to the enzyme through covalent bonds?
Answer
(C)
Irreversible inhibitors
16
What is the primary clinical use of measuring AST?
Answer
(B)
Diagnosis of liver disease
17
What happens to the activation energy when an enzyme is present?
Answer
(B)
It decreases.
18
Which of the following is/are classified as a transferase?
Answer
(D)
All of the above
19
Which of the following is a competitive inhibitor?
Answer
(B)
Ethanol
20
Which type of inhibitor can be overcome by increasing substrate concentration?
Answer
(B)
Competitive Inhibitor
21
How does product concentration affect the rate of an enzyme-catalyzed reaction?
Answer
(D)
High concentrations can inhibit the reaction.
22
What is the value that defines the substrate concentration when the reaction rate is half of its maximum value?
Answer
(B)
Km
23
Which enzyme is elevated in liver diseases?
Answer
(C)
Alanine transaminase
24
Which of the following is the most appropriate description of Km (Michaelis constant)?
Answer
(C)
The substrate concentration at which the reaction rate is half its maximum.
25
Which of the following factors can affect the rate of an enzyme-catalyzed reaction?
Answer
A
B
C
D
26
Which of the following enzymes is inhibited by disulfiram, leading to the buildup of acetaldehyde?
Answer
(B)
Aldehyde dehydrogenase
27
The Lineweaver-Burk plot is used to:
Answer
(B)
Calculate the Km and Vmax values.
28
Which of the following describes the function of the enzyme amylase?
Answer
(C)
Breaks down carbohydrates
29
Which of the following can act as enzyme inhibitors?
Answer
(D)
All of the above.
30
Which of the following are examples of enzymes useful in clinical diagnostics?
Answer
A
B
C
31
What is the main therapeutic use of asparaginase?
Answer
(C)
Treating certain types of leukemia.
32
What effect does a noncompetitive inhibitor have on Vmax and Km?
Answer
(A)
Vmax decreases, Km stays the same
33
In competitive inhibition, the inhibitor usually resembles:
Answer
(A)
The substrate.
34
What is the role of an activator in enzyme kinetics?
Answer
(C)
It enhances the activity of the enzyme.
35
Which of the following enzyme markers are typically evaluated during the diagnosis of myocardial infarction (MI)?
Answer
A
B
C
36
In a Lineweaver-Burk plot, what does the x-intercept represent?
Answer
(B)
-1/Km
37
Which of the following is a characteristic of the transition state?
Answer
(A)
It is the highest energy state during the reaction.
38
Which of the following enzymes is a tetrameric enzyme?
Answer
(A)
Lactate dehydrogenase (LDH)
39
The digestive enzymes belong to:
Answer
(C)
Hydrolases
40
How do enzymes affect the equilibrium of a reaction?
Answer
(C)
They do not affect the equilibrium.
41
Which type of inhibitor increases the Km, but does not change the Vmax?
Answer
(A)
Competitive inhibitor
42
Enzymes are classified into different groups based on:
Answer
(B)
The type of reaction they catalyze.
43
Which of the following is a characteristic of creatine kinase (CK) isoenzymes?
Answer
A
B
C
44
What is the primary function of the enzyme, Lactate Dehydrogenase (LDH)?
Answer
(A)
Catalyzes the oxidation of L-lactate to pyruvate
45
What is the mechanism of action of aspirin?
Answer
(A)
Irreversible inhibitor of cyclooxygenase (COX)
46
Which enzyme is primarily involved in the metabolism of ethanol?
Answer
(B)
Alcohol dehydrogenase
47
At high substrate concentrations, the reaction rate:
Answer
(C)
Reaches a maximum.
48
Which of the following is a key feature of allosteric enzymes?
Answer
B
C
49
Which of the following is a characteristic of irreversible inhibitors?
Answer
(B)
They often form covalent bonds with the enzyme.
50
Which type of inhibition alters the Vmax but not Km?
Answer
(B)
Noncompetitive inhibition