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