Biotransformation Question bank

Q1. Which of the following statements is NOT true about Phase I biotransformation reactions?

a) They introduce or expose functional groups on drugs.
b) They can increase the polarity of drugs.
c) They always make drugs more water-soluble.  
d) They prepare drugs for further metabolism in Phase II.
e) Oxidation, reduction, and hydrolysis are the primary reactions.

Q2. The most common Phase I reaction, primarily catalyzed by CYP450 enzymes, involves:

a) Gain of electrons by the drug molecule.
b) Removal of amine groups from the drug molecule.
c) Addition of oxygen or removal of hydrogen atoms from the drug molecule. 
d) Cleavage of bonds in the drug molecule by water.
e) All of the above.

Q3. N-dealkylation, where an alkyl group is removed from nitrogen, is an example of which Phase I reaction?

a) Oxidation
b) Reduction
c) Hydrolysis
d) None of the above 
e) Requires further information

Q4. Which of the following drugs undergoes conversion to morphine during Phase I biotransformation?

a) Acetaminophen
b) Aspirin
c) Codeine 
d) Lidocaine
e) Sulfadiazine

Q5. In the hydrolysis reaction converting aspirin to salicylic acid, which enzyme is involved?

a) Cytochrome P450
b) Reductase
c) Esterase  
d) Amidase
e) Dehydrogenase

Q6. Which of the following statements about Phase II biotransformation reactions is NOT correct?

A) Phase II reactions involve the conjugation of drugs with an endogenous substance to form water-soluble metabolites.
B) The primary purpose of Phase II reactions is to increase the polarity of drugs and their metabolites to facilitate renal excretion.
C) Glucuronidation, sulfation, and acetylation are examples of Phase II biotransformation reactions.
D) Phase II reactions are typically catalyzed by cytochrome P450 enzymes.
E) Glutathione conjugation is an important Phase II reaction that helps in detoxifying reactive metabolites.

Q7. Which of the following is a primary enzyme involved in glucuronidation?

A) Cytochrome P450
B) UDP-glucuronosyltransferase
C) N-acetyltransferase
D) Glutathione S-transferase
E) Sulfotransferase

Q8. Phase II biotransformation reactions primarily occur in which organ?

A) Kidney
B) Liver
C) Lungs
D) Heart
E) Brain

Q9. Which of the following Phase II reactions involves the addition of a sulfate group to a drug?

A) Glucuronidation
B) Sulfation
C) Acetylation
D) Methylation
E) Glutathione conjugation

Q10. Which of the following is NOT typically a result of Phase II biotransformation?

A) Increased drug polarity
B) Decreased drug toxicity
C) Enhanced renal excretion
D) Formation of reactive intermediates
E) Inactivation of active drugs

Q11. The conjugation of drugs with glutathione primarily serves to:

A) Increase the lipid solubility of drugs
B) Decrease the renal excretion of drugs
C) Detoxify reactive intermediates
D) Increase the duration of drug action
E) Convert drugs into active metabolites

Q12. Which Phase II enzyme is responsible for the conjugation of small endogenous molecules such as acetyl groups to drugs, making them more water-soluble?

A) UDP-glucuronosyltransferase (UGT)
B) N-acetyltransferase (NAT)
C) Glutathione S-transferase (GST)
D) Sulfotransferase (SULT)
E) Methyltransferase

Q13. Which of the following statements about glucuronidation is true?

A) It only occurs in the liver.
B) It always leads to the formation of inactive metabolites.
C) It is an energy-dependent process requiring UDP-glucuronic acid.
D) It is less common than sulfation in drug metabolism.
E) It cannot occur for drugs that contain a hydroxyl group.

Q14. The biotransformation of acetaminophen involves which of the following Phase II pathways as a key detoxification route?

A) Glucuronidation only
B) Sulfation only
C) Glutathione conjugation
D) Acetylation
E) Methylation

Q15. In which condition is the rate of glucuronidation likely to be reduced, potentially leading to drug toxicity?

A) Chronic renal failure
B) Hypothyroidism
C) Hepatic cirrhosis
D) Asthma
E) Hyperlipidemia

Q16. Which Phase II reaction is primarily involved in the metabolism of isoniazid, a drug used to treat tuberculosis?

A) Glucuronidation
B) Sulfation
C) Acetylation
D) Methylation
E) Glutathione conjugation

Q17. Which cofactor is essential for the function of sulfotransferases in Phase II biotransformation?

A) UDP-glucuronic acid
B) Glutathione
C) Acetyl-CoA
D) S-adenosylmethionine (SAM)
E) 3'-Phosphoadenosine-5'-phosphosulfate (PAPS)

Q18. Which of the following factors can lead to increased glucuronidation activity?

A) Advanced age
B) Liver disease
C) Genetic polymorphisms leading to slower enzyme activity
D) Induction by certain drugs or dietary components
E) Renal impairment

Q19. Which of the following factors can lead to increased glucuronidation activity?

A) UDP-glucuronosyltransferase (UGT)
B) N-acetyltransferase (NAT)
C) Glutathione S-transferase (GST)
D) Sulfotransferase (SULT)
E) Methyltransferase

Q20. Which Phase II reaction is commonly involved in the metabolism of bilirubin, a breakdown product of heme?

A) Glucuronidation
B) Sulfation
C) Acetylation
D) Methylation
E) Glutathione conjugation

Q21. Which of the following statements about Phase II reactions is true?

A) They involve the addition of hydroxyl groups to drugs.
B) They primarily occur in the endoplasmic reticulum of cells.
C) They convert lipophilic drugs into more lipophilic metabolites.
D) They do not require cofactors for enzymatic activity.
E) They generally produce inactive metabolites.

Q22. The metabolism of which of the following drugs primarily involves glucuronidation and sulfation pathways?

A) Acetaminophen
B) Morphine
C) Warfarin
D) Isoniazid
E) Amiodarone

Q23. Which Phase II enzyme system is responsible for the methylation of catecholamines and other drugs?

A) UDP-glucuronosyltransferase (UGT)
B) N-acetyltransferase (NAT)
C) Glutathione S-transferase (GST)
D) Sulfotransferase (SULT)
E) Methyltransferase

Q24. The Phase II biotransformation pathway involving glucuronidation is often saturable and can be influenced by:

A) pH of the environment
B) Concentration of endogenous substances
C) Presence of other drugs
D) Temperature of the body
E) Size of the organ

Q25. Which Phase II enzyme system is primarily responsible for the conjugation of drugs with glucuronic acid, increasing their water solubility and facilitating their elimination?

A) UDP-glucuronosyltransferase (UGT)
B) N-acetyltransferase (NAT)
C) Glutathione S-transferase (GST)
D) Sulfotransferase (SULT)
E) Methyltransferase

Q26. In Phase II biotransformation, the formation of mercapturic acid conjugates is associated with which enzyme system?and facilitating their elimination?

A) UDP-glucuronosyltransferase (UGT)
B) N-acetyltransferase (NAT)
C) Glutathione S-transferase (GST)
D) Sulfotransferase (SULT)
E) Methyltransferase

Q27. A deficiency in which Phase II enzyme system can lead to reduced metabolism of estrogens and other endogenous compounds, potentially affecting hormone levels?

A) UDP-glucuronosyltransferase (UGT)
B) N-acetyltransferase (NAT)
C) Glutathione S-transferase (GST)
D) Sulfotransferase (SULT)
E) Methyltransferase

Q28. The metabolism of which of the following drugs primarily involves both glucuronidation and sulfation pathways?

A) Diazepam
B) Lidocaine
C) Warfarin
D) Acetaminophen
E) Morphine

Q29. Which of the following is a MAJOR pathway for the inactivation and detoxification of xenobiotics (foreign chemicals) in the body?

A. Oxidation by CYP450 enzymes 
B. Hydrolysis by esterases
C. Reduction by reductases
D. Decarboxylation
E. All of the above

Q30. A patient with liver cirrhosis is likely to have a:

A. Decreased metabolism of most drugs 
B. Increased metabolism of most drugs
C. No change in drug metabolism
D. Increased metabolism of fat-soluble drugs
E. Increased metabolism of water-soluble drugs

Q31. Which of the following factors can influence drug metabolism?

A. Age 
B. Genetics 
C. Liver disease 
D. All of the above 
E. Only A and B

Q32. CYP3A4 is a major drug-metabolizing enzyme. Which of the following statements about CYP3A4 is FALSE?

A. It is located primarily in the liver 
B. It can be inhibited by some medications 
C. It can be induced by some medications and environmental factors 
D. It metabolizes a wide variety of drugs 
E. It is the only CYP450 enzyme involved in drug metabolism

Q33. Drug-drug interactions can occur when two medications compete for the same metabolic pathway. This can lead to:

A. Increased blood levels of one or both drugs 
B. Decreased blood levels of one or both drugs 
C. Both A and B 
D. No change in blood levels of either drug
E. Increased toxicity of a non-metabolized drug

Q34. A drug containing an alcohol group is most likely to undergo:

A. Oxidation to an aldehyde or carboxylic acid 
B. Reduction to a ketone
C. Hydrolysis
D. Conjugation
E. Decarboxylation

Q35. A drug with a high protein binding percentage will have a:

A. Larger volume of distribution 
B. Smaller volume of distribution
C. No change in volume of distribution
D. Faster elimination rate
E. Slower elimination rate

Q36. The primary route of excretion for most water-soluble drug metabolites is through the:

A. Kidneys 
B. Liver
C. Lungs
D. Skin
E. Feces

Q37. What is the primary cause of acetaminophen toxicity at high doses?

A. Glucuronidation metabolism
B. Sulfate conjugation
C. Glutathione conjugation
D. Glycine conjugation
E. Hydroxylation

Q38. Fluconazole is known for its interaction with which enzyme system?

A. CYP3A4 inhibitor
B. CYP3A4 substrate
C. CYP3A4 inducer
D. CYP2C9 substrate
E. CYP1A2 inhibitor

Q39. Which factor does NOT affect drug metabolism in the liver?

A. tissue binding
B. changes with liver blood circulation
C. changes with intrinsic activity
D. chronic liver diseases
E. Oxidative metabolism catalyzed by cytochrome CYP450

Q40. Which medication combination poses an increased risk of myopathy when used with simvastatin?

A. Azithromycin
B. Nifedipine
C. Fluconazole
D. Diltiazem
E. No effect. Can take safely.

Q41. Smoking affects drug metabolism primarily by acting as a:

A. Enzyme inhibitor
B. Enzyme substrate
C. Cytochrome polymorphism inducer
D. Enzyme inducer
E. Enzyme inhibitor and substrate