Multiple forms of the same enzymes are also referred to as
Хариулт
(B)
Isoenzymes
2
In a scenario of non-competitive enzyme behavior
Хариулт
(C)
Apparent km decreases
3
How does an allosteric enzyme influence enzymatic activity?
Хариулт
(C)
By changing the enzyme's conformation through binding at a site other than the catalytic site
4
Which regulatory process involves a reversible change to an enzyme through a covalent modification?
Хариулт
(A)
Phosphorylation of serine OH on the enzyme
5
What characterizes a competitive enzyme inhibitor?
Хариулт
(D)
It prevents the substrate from binding to the enzyme
6
When [s] equals K, which of the following statements is correct?
Хариулт
(A)
Half of the enzyme molecules are bound to substrate
7
Which statement is incorrect concerning an enzyme demonstrating allosteric kinetics with cooperative interaction?
Хариулт
(D)
Removing an allosteric inhibitor might result in a hyperbolic V vs. [s] plot
8
Pantothenic acid plays a crucial role in the function of
Хариулт
(B)
NADPH
9
Which of the following is not a vitamin deficiency associated with fatty liver?
Хариулт
(C)
Retinoic acid
10
In which type of enzyme is an inducer not required?
Хариулт
(D)
Constitutive enzyme
11
Which type of enzyme facilitates the addition of water to a carbon-carbon double bond without breaking the bond?
Хариулт
(B)
Hydratase
12
The 'Lock and Key' model of enzyme action, proposed by Fisher, suggests that
Хариулт
(C)
The active site shape matches the substrate
13
In enzyme action competitive inhibition, what is the impact?
Хариулт
(B)
The apparent Km is increased
14
What is the correct kinetic effect during competitive inhibition?
Хариулт
(D)
Increases Km without affecting Vmax
15
How do enzymes accelerate reaction rates?
Хариулт
(B)
Decreasing the energy of activation
16
What is the most helpful test for diagnosing acute hemorrhagic pancreatitis in the initial days?
Хариулт
(D)
Serum amylase
17
Which test is best for diagnosing acute pancreatitis if mumps is also present?
Хариулт
(D)
Serum lipase
18
Which condition often shows an increase in the slow-moving fraction of LDH in the pancreas?
Хариулт
(D)
Acute viral hepatitis
19
Which enzyme is often elevated in individuals with alcoholism?
Хариулт
(C)
Serum γ-GT
20
Compared to those with purely obstructive jaundice, individuals with hepatocellular jaundice are likely to have
Хариулт
(B)
Lower serum ALP, Higher LDH and AST activity
21
If results from serum bilirubin, serum ALP, LDH, and AST tests indicate potential obstructive jaundice, what is the most effective test to confirm the diagnosis?
Хариулт
(B)
Serum 5' nucleotidase
22
Which enzyme test is most useful for distinguishing between elevated serum ALP levels caused by obstructive jaundice versus bone disorders?
Хариулт
(D)
Serum γ-GT
23
What CK isoenzyme is primarily found in cardiac muscle?
Хариулт
(D)
MM and MB only
24
What LDH isoenzyme fraction typically shows a proportionate increase in liver and skeletal muscle disorders?
Хариулт
(C)
LDH-3 and LDH-4
25
Following an acute myocardial infarction, what enzyme test provides the best predictive value on the third day?
Хариулт
(D)
Serum LDH
26
Which of the following conditions is NOT typically associated with elevated serum AST activity?
Хариулт
(D)
Peptic ulcer
27
When is the estimation of serum AST most significant following an acute myocardial infarction?
Хариулт
(B)
Second day
28
In which of the following organ diseases would LDH-1 and LDH-2 isoenzymes be released into the plasma?
Хариулт
(B)
Heart, Kidney and R.B.C
29
What is true about non-functional enzymes in plasma?
Хариулт
(D)
All of these
30
Which of the following is NOT a component of pyruvate dehydrogenase?
Хариулт
(A)
Biotin
31
Elevated levels of LDH-5 are typically observed in all of the following conditions EXCEPT:
Хариулт
(D)
Pulmonary embolism
32
What substance is broken down by the enzyme diastase?
Хариулт
(B)
Starch
33
Which of the following statements accurately describes enzymes?
Хариулт
(B)
Enzymes are highly specific in their action
34
What factors influence the activity of an enzyme?
Хариулт
(E)
All of these
35
Which statement about enzymes is INCORRECT?
Хариулт
(C)
They are destroyed after the completion of the reaction they catalyse
36
Approximately how many distinct enzymes have been identified?
Хариулт
(C)
50
37
What type of compound is nicotine, found in tobacco?
Хариулт
(A)
Alkaloid
38
The toxic alkaloid found in hemlock oil is:
Хариулт
(A)
Cocaine
39
What solvent is commonly used to extract alkaloids during purification?
Хариулт
(B)
Dil HCl
40
Which reagent is most useful for estimating the number of N-MC groups in alkaloids?
Хариулт
(A)
HI
41
In the context of enzyme kinetics, a competitive inhibitor
Хариулт
(A)
Raises the Km value while leaving the Vmax unchanged
42
Regarding the Michaelis constant (Km), which statement is accurate?
Хариулт
(D)
It represents the substrate concentration at which the reaction velocity is half of its maximum
43
When assessing an enzyme-catalyzed reaction with substrate concentrations significantly below Km, what best describes the relationship between reaction velocity and substrate concentration?
Хариулт
(D)
Directly proportional to the substrate concentration
44
What is the impact of a non-competitive inhibitor?
Хариулт
(B)
It causes a reduction in the observed Vmax
45
Which characteristic is NOT generally associated with allosteric enzymes?
Хариулт
(C)
They adhere to Michaelis-Menten kinetics
46
An atypical isoenzyme does NOT necessarily
Хариулт
(A)
Function as an oxidoreductase
47
LDH assays are most valuable in diagnosing conditions affecting the
Хариулт
(A)
Cardiac muscle
48
What type of chemical interactions are primarily responsible for the binding of coenzymes and substrates to enzymes like LDH?
Хариулт
(D)
Covalent bonds
49
How many distinct protein forms can be found in normal LDH?
