Clinical Significance of Enzymes: Diagnostic and Therapeutic Applications

Question 1

Enzyme inhibitors are substances that:

Accepted Answer

Reduce the rate of enzyme-catalyzed reactions

Answer

Enhance the rate of enzyme-catalyzed reactions

Answer

Have no effect on the rate of enzyme-catalyzed reactions

Answer

Are either competitive or non-competitive

Question 2

Which of these is NOT a clinical application of enzyme inhibitors?

Accepted Answer

Treating bacterial infections

Answer

Treating high blood pressure

Answer

Preventing blood clots

Answer

Treating cancer

Question 3

How do competitive and non-competitive enzyme inhibitors differ?

Accepted Answer

Competitive inhibitors bind to the active site, while non-competitive inhibitors bind elsewhere on the enzyme

Answer

Competitive inhibitors increase enzyme reaction rates, while non-competitive inhibitors decrease them

Answer

Non-competitive inhibitors bind to the enzyme-substrate complex, while competitive inhibitors bind to the free enzyme

Answer

Competitive inhibitors are reversible, while non-competitive inhibitors are irreversible

Question 4

Which of the following is an example of a non-competitive enzyme inhibitor?

Accepted Answer

Cyanide

Answer

Aspirin

Answer

Metformin

Answer

Warfarin

Question 5

Which enzyme's elevated blood levels are most indicative of muscle damage?

Accepted Answer

Creatine kinase (CK)

Answer

Alanine aminotransferase (ALT)

Answer

Lactate dehydrogenase (LDH)

Answer

Troponin

Question 6

Asparaginase is a therapeutic enzyme used to treat acute lymphoblastic leukemia. How does it achieve this therapeutic effect?

Accepted Answer

Asparaginase breaks down asparagine, depriving leukemia cells of an essential amino acid, leading to their death.

Answer

Asparaginase blocks DNA synthesis in leukemia cells, preventing their growth and replication.

Answer

Asparaginase stimulates the immune system to identify and destroy leukemia cells.

Question 7

Which enzyme is highly sensitive and specific for diagnosing acute myocardial infarction?

Accepted Answer

Creatine kinase-MB

Answer

Aspartate aminotransferase

Answer

Lactate dehydrogenase

Answer

Alanine aminotransferase

Question 8

Which enzyme catalyzes the hydrolysis of urea, a pivotal step in nitrogen metabolism?

Accepted Answer

Urease

Answer

Pepsin

Answer

Trypsin

Answer

Chymotrypsin

Question 9

Define the active site of an enzyme:

Accepted Answer

A specific region on the enzyme that binds to and catalyzes the substrate

Answer

A general region on the enzyme that is not involved in catalysis

Answer

The entire surface of the enzyme involved in catalysis

Answer

A region on the enzyme that binds to cofactors or coenzymes

Question 10

Which of the following is NOT a recognized mechanism of enzyme inhibition?

Accepted Answer

Allosteric modulation

Answer

Competitive inhibition

Answer

Non-competitive inhibition

Answer

Uncompetitive inhibition

Question 11

Identify the enzyme responsible for catalyzing the formation of new peptide bonds:

Accepted Answer

Ligase

Answer

Peptidase

Answer

Transferase

Answer

Hydrolase

Question 12

Elevated serum creatinine kinase (CK) indicates which condition?

Accepted Answer

Myocardial infarction

Answer

Liver disease

Answer

Renal failure

Answer

Pancreatitis

Question 13

Which enzyme is used to dissolve blood clots?

Accepted Answer

Streptokinase

Answer

Asparaginase

Answer

Glucose oxidase

Answer

Lactate dehydrogenase

Question 14

Which enzyme converts bilirubin into a water-soluble form?

Accepted Answer

Glucuronosyltransferase

Answer

Aminotransferase

Answer

Dehydrogenase

Answer

Kinase

Question 15

Which clinical condition results from a deficiency of lysosomal enzymes?

Accepted Answer

Phenylketonuria

Answer

Gout

Answer

Diabetes

Answer

Hypertension

Question 16

Which enzyme is a highly specific diagnostic marker for myocardial infarction?

Accepted Answer

Creatine kinase MB

Answer

Alanine aminotransferase

Answer

Lipase

Answer

Amylase

Question 17

Elevated levels of which enzyme are indicative of obstructive jaundice?

Accepted Answer

Alkaline phosphatase

Answer

Lactate dehydrogenase

Answer

Gamma-glutamyl transferase

Answer

Aspartate aminotransferase

Question 18

Which enzyme deficiency is associated with Gaucher's disease?

Accepted Answer

Glucocerebrosidase

Answer

Lysosomal acid lipase

Answer

Sphingomyelinase

Answer

Hexosaminidase A

Question 19

Which type of enzyme inhibition is reversible and characterized by competition between the substrate and inhibitor for the active site of the enzyme?

Accepted Answer

Competitive inhibition

Answer

Uncompetitive inhibition

Answer

Mixed inhibition

Answer

Non-competitive inhibition

Question 20

Elevated levels of which enzyme in the serum are most indicative of a myocardial infarction (heart attack)?

Accepted Answer

Creatine kinase-MB (CK-MB)

Answer

Lipase

Answer

Alkaline phosphatase (ALP)

Answer

Amylase

Question 21

A patient presents with jaundice, fatigue, and abdominal pain. Which enzyme, if significantly elevated, would suggest a diagnosis of acute pancreatitis?

Accepted Answer

Lipase

Answer

Lactate dehydrogenase (LDH)

Answer

Aspartate transaminase (AST)

Answer

Alanine transaminase (ALT)

Question 22

Which of the following enzymes is used in the treatment of Acute Lymphoblastic Leukemia (ALL)?

Accepted Answer

Asparaginase

Answer

Urokinase

Answer

Streptokinase

Answer

DNAse

Question 23

Elevated serum levels of alanine transaminase (ALT) and aspartate transaminase (AST) are most indicative of damage to which organ?

Accepted Answer

Liver

Answer

Kidney

Answer

Pancreas

Answer

Heart

Question 24

Which enzyme is a tumor marker for prostate cancer, although its specificity has been questioned in recent years?

Accepted Answer

Prostate-specific antigen (PSA)

Answer

Carcinoembryonic antigen (CEA)

Answer

Alpha-fetoprotein (AFP)

Question 25

Which enzyme deficiency is responsible for the most common form of Galactosemia?

Accepted Answer

Galactose-1-phosphate uridyltransferase (GALT)

Answer

Sucrase

Answer

Amylase

Answer

Lactase

Question 26

What is the mechanism of action of tissue plasminogen activator (tPA) in treating ischemic stroke?

Accepted Answer

Converts plasminogen to plasmin, which dissolves blood clots.

Answer

Inhibits platelet aggregation.

Answer

Dilates blood vessels.

Question 27

Which enzyme is responsible for the breakdown of lactose into glucose and galactose?

Accepted Answer

Lactase

Answer

Amylase

Answer

Sucrase

Answer

Maltase

Question 28

Elevated levels of which enzyme are indicative of muscle damage, such as in muscular dystrophy?

Accepted Answer

Creatine kinase (CK)

Answer

Gamma-glutamyl transpeptidase (GGT)

Answer

Lipase

Answer

Alkaline phosphatase (ALP)