Sign In

Essential Biochemistry - Enzymes (Section 6)

1
In allosteric enzyme regulation, an enzyme is specifically for:
Answer
(A)
Its substrate
2
Which enzyme is directly inhibited by DFP?
Answer
(B)
Acetylcholinesterase
3
Which type of inhibitor binds only to the enzyme-substrate complex?
Answer
(C)
Uncompetitive
4
What is the effect of a noncompetitive inhibitor on Vmax?
Answer
(A)
Decreases
5
Noncompetitive inhibitors bind to the:
Answer
(B)
Allosteric site
6
The elevation of which enzyme is strongly associated with myocardial infarction?
Answer
(B)
CK-MB
7
In allosteric regulation, the modulator binds to:
Answer
(B)
The allosteric site.
8
Dilsulfiram's mechanism of action involves inhibition of:
Answer
(A)
Aldehyde dehydrogenase
9
Transaminase enzymes belong to the class:
Answer
(B)
Transferases
10
Competitive inhibitors bind to the:
Answer
(A)
Active site
11
Which of the following describes the lock-and-key model of enzyme-substrate interaction?
Answer
(C)
The substrate fits perfectly into the active site.
12
What type of inhibitor binds to a site other than the active site, altering the enzyme's shape?
Answer
(B)
Noncompetitive
13
DDT's mode of action, classifying it as an inhibitor, is:
Answer
(C)
Group-specific irreversible
14
In obstructive jaundice, which enzymes increase?
Answer
B
C
15
In a Lineweaver-Burk plot, the x-intercept represents:
Answer
(A)
-1/Km
16
The Michaelis constant (Km) is a measure of:
Answer
(B)
The substrate concentration at half Vmax
17
Amylase is increased in:
Answer
(A)
Acute pancreatitis
18
What is the effect of a competitive inhibitor on Vmax?
Answer
(C)
No change
19
Dilsulfiram's effect results in what physiological consequence?
Answer
(B)
Build-up of acetaldehyde.
20
LDH1 is a tetramer, made up of two types of polypeptide:
Answer
(A)
M (muscle) type and H(heart) type
21
Which of the following is an example of an isomerase?
Answer
(C)
Mutase
22
Examples of noncompetitive inhibitors are:
Answer
(D)
All of the above
23
Which of the following enzyme classes is involved in joining two molecules together with the hydrolysis of ATP?
Answer
(A)
Ligases
24
The LDH1 isozyme is composed of:
Answer
(C)
H and M subunits.
25
Which is an example of a group-specific irreversible inhibitor?
Answer
(A)
DDT
26
Which of the following affects the velocity of an enzyme-catalyzed reaction?
Answer
A
B
C
D
27
In feedback inhibition, the enzyme inhibited is typically:
Answer
(B)
The first enzyme in the pathway.
28
Which enzyme does DFP primarily target?
Answer
(B)
Acetylcholinesterase
29
The digestive enzymes belong to:
Answer
(C)
Hydrolases
30
The isozymes are classified according to:
Answer
(B)
The type of catalyst
31
In feedback inhibition, the product of the pathway acts as an inhibitor. Which enzyme does this product inhibit?
Answer
(B)
The first enzyme in the pathway
32
What is the principal use of Asparaginase?
Answer
(B)
Leukemia treatment
33
The substrate concentration at which an enzyme inhibitor has half the maximum velocity is known as:
Answer
(B)
Km
34
Penicillin functions as what type of inhibitor?
Answer
(C)
Mechanism-based (suicide)
35
Which of these enzymes is elevated in acute pancreatitis?
Answer
(C)
Both Amylase and Lipase
36
Which applications utilize enzymes?
Answer
A
B
C
37
Elevation of CK-MB is indicative of:
Answer
(B)
Myocardial infarction.
38
Which of the following is true regarding the Lineweaver-Burk plot?
Answer
(B)
It is a double-reciprocal plot.
39
What happens to the free energy of activation in the presence of an enzyme?
Answer
(B)
It decreases
40
Which of the following drugs are noncompetitive inhibitors?
Answer
(D)
All of the above
41
Which of the following non-proteins can act as an enzyme?
Answer
(B)
RNA
42
Where is CK-MB primarily found?
Answer
(A)
Cardiac muscle
43
Aspirin is primarily used to inhibit:
Answer
(B)
Cyclooxygenase
44
What happens to enzyme activity at high temperatures?
Answer
(B)
It decreases
45
Which of the following is an example of group specific irreversible inhibitor?
Answer
(A)
DDT
46
Irreversible inhibitors form:
Answer
(A)
A stable complex with the enzyme
47
Which is an example of a suicide inhibitor?
Answer
(B)
Penicillin
48
Which is an example of an enzyme that can be used for diagnostic purposes?
Answer
(D)
All of the above
49
Which of the following is an example of suicide inhibitor or mechanism based inactivation?
Answer
(B)
Penicillin
50
LDH1 is composed of which subunit types?
Answer
(A)
H and M