(P) CC2 Lec L5-L6

https://docs.google.com/document/d/1xTfIrAZGDxzyiCdJMffvONLVIeuQ9cKuO7-Ty1M7QWk/edit?tab=t.0

B

What is the systematic biochemical name for Amylase?

• a. Triacylglycerol Acylhydrolase

• b. alpha-1,4-Glucan-4-Glucohydrolase

• c. Creatine N-phosphotransferase

• d. Pyruvate Kinase

• e. Glucose-6-Phosphate Dehydrogenase

C

Which enzyme is recognized as the smallest enzyme in human plasma by molecular weight (50,000 to 55,000 Da)?

• a. Lipase

• b. Creatine Kinase

• c. Amylase

• d. Lactate Dehydrogenase

• e. Alkaline Phosphatase

E

Which cofactors are obligatorily required for the enzymatic activation of Amylase?

• a. Magnesium (Mg^2+) and Zinc (Z^2+)

• b. Sodium (Na^+) and Bicarbonate (HCO3^-)

• c. Iron (Fe^2+) and Copper (Cu^2+)

• d. Manganese (Mn^2+) and Potassium (K^+)

• e. Calcium (Ca^2+) and Chloride (Cl^-)

B

What is the primary clinical distinction of serum Amylase in acute pancreatitis diagnosis?

• a. It is the most specific marker for liver disease

• b. It is the earliest pancreatic marker to elevate following tissue injury

• c. It remains elevated for 2 to 3 weeks

• d. It is exclusively produced by pancreatic acinar cells

• e. It decreases significantly during acute inflammation

D

Within what time frame does serum Amylase typically begin to elevate following acute pancreatic tissue injury?

• a. 30 minutes to 1 hour

• b. 3 to 5 days

• c. 24 to 48 hours

• d. 2 to 12 hours

• e. 7 to 10 days

C

Serum Amylase levels typically reach peak elevation during acute pancreatitis at:

• a. 6 hours

• b. 12 hours

• c. 24 hours

• d. 48 hours

• e. 72 hours

A

How long does it take for serum Amylase levels to return to baseline following an acute pancreatitis episode?

• a. 3 to 5 days

• b. 24 to 36 hours

• c. 12 to 24 hours

• d. 8 to 14 days

• e. 3 to 4 weeks

B

Which Amylase isoenzyme is referred to as Ptyalin and migrates fastest toward the anode during electrophoresis?

• a. Pancreatic Amylase

• b. Salivary Amylase

• c. Cardiac Amylase

• d. Hepatic Amylase

• e. Renal Amylase

B

What specific substance explicitly inhibits Salivary Amylase (Ptyalin)?

• a. Olive oil

• b. Wheat germ lectin

• c. N-acetylcysteine

• d. Sodium citrate

• e. EDTA

E

Which Amylase isoenzyme is also known as Amylopsin and migrates slowest toward the anode?

• a. Salivary Amylase

• b. Intestinal Amylase

• c. Hepatic Amylase

• d. Renal Amylase

• e. Pancreatic Amylase

A

Why are calcium-binding anticoagulants (such as EDTA, Citrate, and Oxalate) strictly prohibited for Amylase specimen collection?

• a. They chelate free Ca^2+, leading to complete enzyme inactivation

• b. They cause severe hemolysis in RBCs

• c. They interfere with 340 nm absorbance reading

• d. They degrade starch into non-reducing sugars

• e. They trigger auto-activation of proenzymes

B

How does hemolysis affect serum Amylase determination?

• a. RBCs release high concentrations of Amylase

• b. Hemolysis does not interfere with classical methods but WILL interfere with coupled enzymatic procedures

• c. Hemolysis causes a false decrease in all Amylase methods

• d. Hemolysis destroys the starch substrate immediately

• e. Hemolysis produces a false normal reading in all assay types

E

If a serum sample contains extremely high Amylase activity, what diluent should be used to prevent enzyme inactivation/substrate depletion?

• a. Deionized water

• b. 5% Dextrose solution

• c. Reagent grade ethanol

• d. Phosphate buffered formalin

• e. Sodium chloride (NaCl)

B

What effect does hypertriglyceridemia (hyperlipemia) have on serum Amylase measurements in patients with acute pancreatitis?

• a. Falsely elevates serum Amylase activity

• b. Inhibits/suppresses serum Amylase, causing falsely normal levels

• c. Has no effect on Amylase activity

• d. Causes immediate precipitation of Amylase isoenzymes

• e. Accelerates Amylase clearance in urine

A

What is the mechanism by which morphine and opiates cause false elevation of serum Amylase?

• a. They cause constriction of the sphincter of Oddi and pancreatic duct, forcing Amylase regurgitation into serum

• b. They stimulate acinar cells to overproduce Amylase

• c. They act as sulfhydryl activators in circulation

• d. They inhibit renal clearance of Amylase

• e. They bind to wheat germ lectin and activate Ptyalin

B

Which non-enzymatic substrate is universally used in classic Amylase assays?

• a. Triolein

• b. Starch

• c. Olive oil

• d. Creatine phosphate

• e. Maltopentose

C

The classic reference method for Amylase that measures the quantity of reducing sugars liberated from starch hydrolysis is the:

• a. Amyloclastic Method

• b. Chromogenic Method

• c. Saccharogenic Method

• d. Cherry-Crandall Method

• e. Oliver-Rosalki Method

B

What unit of measurement is traditionally associated with the Saccharogenic method for Amylase?

• a. International Units (IU/L)

• b. Somogyi Units (SU)

• c. Bodansky Units (BU)

• d. King-Armstrong Units (KAU)

• e. Karmen Units (KU)

A

What conversion factor (CF) is used to convert Amylase values from SI Units to Somogyi Units?

• a. 1.85

• b. 1.00

• c. 2.50

• d. 6.00

• e. 12.0

B

Which Amylase assay measures enzyme activity by monitoring the rate of decrease in starch concentration over time?

• a. Saccharogenic Method

• b. Amyloclastic Method

• c. Chromogenic Method

• d. Coupled-Enzyme Method

• e. Titrimetric Method

C

Which method for Amylase utilizes a starch substrate bound to an insoluble dye and measures the increase in color intensity of liberated dye-substrate complexes?

• a. Saccharogenic Method

• b. Amyloclastic Method

• c. Chromogenic Method

• d. Tanzer-Gilvarg Method

• e. Cherry-Crandall Method

B

In automated continuous monitoring coupled-enzyme reactions for Amylase, absorbance change is measured at 340 nm due to the conversion of:

• a. NADH to NAD^+

• b. NAD^+ to NADH

• c. NADPH to NADP^+

• d. ATP to ADP

• e. Creatine to Phosphocreatine

B

What is the systematic name for Lipase?

• a. alpha-1,4-Glucan-4-Glucohydrolase

• b. Triacylglycerol Acylhydrolase

• c. Creatine N-phosphotransferase

• d. Pyruvate Kinase

• e. Lactate Dehydrogenase

E

What primary reaction is catalyzed by Lipase?

• a. Transfer of a phosphate group from ATP to creatine

• b. Oxidation of glucose-6-phosphate to 6-phosphogluconate

• c. Hydrolysis of alpha-1,4-glucosidic bonds in starch

• d. Reduction of pyruvate to lactate

• e. Hydrolysis of ester linkages in fats to yield glycerol/alcohol and free fatty acids

B

What is the protein cofactor that binds to Lipase in a 1:1 ratio to anchor it directly to the lipid emulsion surface in the presence of bile salts?

• a. Ptyalin

• b. Colipase

• c. Cysteine

• d. Adenylate Kinase

• e. Albumin

A

What role do bile salts play in Lipase enzymatic activity?

• a. They act as essential co-activators and emulsifiers that break large fat globules into microscopic droplets

• b. They chelate free calcium ions

• c. They directly hydrolyze ester bonds in triglycerides

• d. They inhibit bacterial lipases

• e. They oxidize NADH to NAD^+

A

Why is Calcium (Ca^2+) required for optimal Lipase reaction rates?

• a. It binds to released free fatty acids to form insoluble calcium soaps, preventing FFA accumulation from inhibiting the enzyme

• b. It acts as an anodal marker during electrophoresis

• c. It binds directly to colipase to form a dimer

• d. It inactivates adenylate kinase

• e. It converts maltotriose into glucose

B

Compared to Amylase, serum Lipase is considered:

• a. Less specific for pancreatic disease

• b. Vastly more specific for acute pancreatitis

• c. An earlier marker that rises within 30 minutes

• d. Present in high concentrations in normal urine

• e. Rapidly cleared within 12 hours

A

When does serum Lipase typically begin to elevate (initial elevation) after the onset of acute pancreatitis?

• a. 2 to 12 hours

• b. 3 to 4 weeks

• c. 24 to 48 hours

• d. 8 to 14 days

• e. 2 to 4 days

C

How long does serum Lipase remain elevated following acute pancreatitis, providing a significantly longer diagnostic window than Amylase?

• a. 12 to 24 hours

• b. 3 to 5 days

• c. 8 to 14 days

• d. 20 to 30 days

• e. 1 to 2 months

B

Why is Lipase NOT present in normal urine?

• a. It cannot pass through the renal glomerulus due to massive size

• b. It is reabsorbed by the renal tubules

• c. It is destroyed by urinary pH immediately

• d. It is converted into Amylase in the nephron

• e. It is bound to IgA in glomerular filtrate

B

How does hemolysis affect serum Lipase measurements?

• a. Causes false elevation due to RBC Lipase release

• b. Causes false decrease because free hemoglobin directly inhibits Lipase enzyme activity

• c. Has no effect on Lipase activity whatsoever

• d. Causes turbidity which increases absorbance falsely

• e. Accelerates colipase binding to lipid droplets

D

Bacterial contamination in a specimen causes what analytical error in serum Lipase testing?

• a. False decrease due to enzyme digestion

• b. Complete loss of color development

• c. Inactivation of colipase

• d. False increase due to bacterial lipases

• e. Chelation of calcium ions

C

What is the classic reference method for serum Lipase determination?

• a. Oliver-Rosalki Method

• b. Tanzer-Gilvarg Method

• c. Cherry-Crandall Method

• d. Saccharogenic Method

• e. Amyloclastic Method

B

What substrate was traditionally used in the classic Cherry-Crandall method for Lipase?

• a. Starch emulsion

• b. Olive oil substrate

• c. Maltopentose

• d. Creatine phosphate

• e. Wheat germ lectin

B

In modern modifications of Lipase assays, which pure triglyceride substrate is commonly substituted for olive oil?

• a. Dextrin

• b. Triolein

• c. Glycogen

• d. Maltotetrose

• e. Phosphocreatine

C

Which Lipase method measures the rate of clearing (reduction in turbidity) as Lipase cleaves fat in an emulsion?

• a. Titrimetric Method

• b. Saccharogenic Method

• c. Turbidimetric Method

• d. Electrophoretic Method

• e. Amyloclastic Method

C

What is the reference range for serum Lipase?

• a. 30–220 U/L

• b. 60–180 SU/dL

• c. < 38 U/L

• d. 6.5–48.1 IU/h

• e. 500–1000 U/L

A

What reaction is catalyzed by Creatine Kinase (CK)?

• a. Reversible transfer of a phosphate group between ATP and creatine

• b. Hydrolysis of starch to glucose and maltose

• c. Hydrolysis of triglyceride ester linkages to free fatty acids

• d. Conversion of lactate to pyruvate

• e. Cleavage of maltopentose to glucose

C

Which metallic ion is an obligatory activator required for Creatine Kinase activity?

• a. Calcium (Ca^2+)

• b. Chloride (Cl^-)

• c. Magnesium (Mg^2+)

• d. Copper (Cu^2+)

• e. Sodium (Na^+)

A

Besides magnesium, what type of chemical activator is mandatory in CK reagents to restore activity of oxidized thiol groups?

• a. Sulfhydryl / thiol activator (e.g., N-acetylcysteine, DTT, Glutathione)

• b. Calcium-chelating agent (e.g., EDTA)

• c. Lectin inhibitor (e.g., Wheat germ lectin)

• d. Bile salt emulsifier

• e. Chromogenic dye

B

Which metal ions actively inhibit and suppress Creatine Kinase activity?

• a. Calcium and Chloride

• b. Zinc (Zn^2+) and Manganese (Mn^2+)

• c. Sodium and Potassium

• d. Magnesium and Iron

• e. Bicarbonate and Phosphate

C

Creatine Kinase exists as a dimer made up of which two distinct protein subunits?

• a. Alpha and Beta

• b. Heavy (H) and Light (L)

• c. Muscle (M) and Brain (B)

• d. Pancreatic (P) and Salivary (S)

• e. Isoform 1 and Isoform 2

C

Which CK isoenzyme is designated as CK-1, migrates fastest toward the anode during electrophoresis, and originates predominantly from brain and CNS tissue?

• a. CK-MM

• b. CK-MB

• c. CK-BB

• d. CK-Mit

• e. Macro-CK

B

Which CK isoenzyme is known as the hybrid type, designated as CK-2, and is associated primarily with myocardium?

• a. CK-BB

• b. CK-MB

• c. CK-MM

• d. CK-Mit

• e. Ptyalin

C

Which CK isoenzyme represents approximately 95% of total serum CK in healthy individuals and originates primarily from skeletal muscle?

• a. CK-BB (CK-1)

• b. CK-MB (CK-2)

• c. CK-MM (CK-3)

• d. CK-Mit

• e. Amylopsin

A

Where is Mitochondrial CK (CK-Mit) located, and what is its migration pattern on electrophoresis?

• a. Inner mitochondrial membrane; strictly cathodal to CK-MM

• b. Outer nuclear membrane; most anodal fraction

• c. Cytosol; migrates between CK-BB and CK-MB

• d. Cell membrane; migrates with albumin

• e. Serum surface; does not migrate

C

What does the presence of CK-Mit in serum signify clinically?

• a. Normal skeletal muscle turnover

• b. Acute salivary gland inflammation

• c. Severe tissue necrosis and cellular destruction

• d. Mild physical exercise

• e. Morphine administration

D

Which major organ is notable for completely lacking Creatine Kinase (CK IS NOT present in this organ)?

• a. Brain

• b. Skeletal Muscle

• c. Heart

• d. Liver

• e. Smooth Muscle

B

Following an acute myocardial infarction (AMI), when does CK-MB typically begin to elevate in serum?

• a. 30 minutes to 1 hour

• b. 4 to 8 hours

• c. 12 to 24 hours

• d. 48 to 72 hours

• e. 5 to 7 days

B

At what point post-myocardial infarction does CK-MB reach its peak concentration?

• a. 2 to 4 hours

• b. 12 to 24 hours

• c. 36 to 48 hours

• d. 72 to 96 hours

• e. 10 to 14 days

C

How long post-AMI does serum CK-MB typically return to baseline levels?

• a. 12 hours

• b. 24 hours

• c. 48 to 72 hours

• d. 7 to 10 days

• e. 14 to 21 days

A

Which clinical condition produces the highest elevation of total serum CK (up to 50 to 100 times normal)?

• a. Duchenne's Muscular Dystrophy

• b. Delirium Tremens

• c. Pulmonary Infarction

• d. Mumps

• e. Acute Cholecystitis

B

Why must hemolyzed samples NOT be used for Creatine Kinase testing?

• a. RBCs contain massive amounts of CK-BB

• b. RBCs contain Adenylate Kinase (AK), which reacts with ADP to form ATP + AMP, causing false elevation

• c. Free hemoglobin directly destroys phosphocreatine

• d. Hemolysis prevents magnesium activation

• e. Hemolysis turns the substrate cloudy, blocking light at 340 nm

B

What specimen handling requirement is critical for preserving CK activity due to its light sensitivity?

• a. Samples must be kept at 37°C continuously

• b. Samples must be stored in the dark / wrapped in foil because CK is rapidly inactivated by light

• c. Samples must be treated with wheat germ lectin

• d. Samples must be collected in sodium fluoride tubes

• e. Samples must be vigorously vortexed

E

56. In the Tanzer-Gilvarg method for measuring CK, what is the reaction direction and optimal pH?

• a. Reverse reaction; pH 6.8

• b. Coupled enzymatic; pH 6.9

• c. Reverse reaction; pH 9.0

• d. Forward reaction (Creatine > Creatine Phosphate); pH 6.8

• e. Forward reaction (Creatine > Creatine Phosphate); pH 9.0

B

What indicator system change is monitored at 340 nm in the Tanzer-Gilvarg (forward) CK method?

• a. Increase in absorbance as NADP^+ is reduced to NADPH

• b. Decrease in absorbance as NADH is oxidized to NAD^+

• c. Increase in absorbance as NADH is reduced

• d. Color intensity increase of a chromogenic dye

• e. Rate of clearing in turbidity

A

What is the direction of reaction and optimal pH for the Oliver-Rosalki method for CK?

• a. Reverse reaction (Creatine Phosphate > Creatine); pH 6.8

• b. Forward reaction; pH 9.0

• c. Forward reaction; pH 6.8

• d. Reverse reaction (Creatine Phosphate > Creatine); pH 9.0

• e. Hydrolytic reaction; pH 7.4

B

What indicator system change is monitored at 340 nm in the Oliver-Rosalki (reverse) CK method?

• a. Decrease in absorbance as NADH is oxidized to NAD^+

• b. Increase in absorbance as NADP^+ is reduced to NADPH

• c. Clearing of turbid lipid emulsion

• d. Titration of fatty acids with NaOH

• e. Color loss of starch-dye complex

E

Why is the Oliver-Rosalki method preferred and standardized over the Tanzer-Gilvarg method as the reference method for routine clinical CK testing?

• a. It does not require any sulfhydryl activators or magnesium

• b. It uses olive oil as a natural substrate

• c. It is not affected by adenylate kinase cross-reactivity

• d. It directly measures amylase isoenzymes simultaneously

• e. It operates at a 2 to 6 times faster rate with superior enzyme stability and analytical sensitivity