Which of the following statements about metabolism is TRUE:

Question

BlackTom AI · Accepted Answer

Question restatement: Which of the following statements about metabolism is TRUE?

Option a: 'CYP3A4 is the most abundant Phase II metabolic enzyme and is responsible for metabolising the majority of drugs on the market.' This is inaccurate because CYP3A4 is a Phase I (not Phase II) enzyme that mainly carries out oxidation reactions; while it metabolizes many drugs, it is not categorized as a Phase II enzyme, and it is not correct to claim it is the most abundant Phase II enzyme or that it metabolizes the majority of drugs on the market.

Option b: 'Drug metabolising enzymes are responsible for the clearance of many drug molecules from the plasma.' This statement is correct. Drug-metabolizing enzymes (primarily Phase I and Phase II enzymes in the liver and other tissues) transform lipophilic drugs into more hydrophilic forms, facilitating elimination from the bloodstream and body. This describes the fundamental purpose of drug metabolism and clearance.

Option c: 'Most drug metabolising enzymes are found in microsomes in the kidneys.' This is misleading. While some drug-metabolizing activity occurs in the kidneys, the liver (specifically hepatic microsomes containing cytochrome P450 enzymes) is the primary site of drug metabolism. Renal microsomes do exist, but they contribute a much smaller portion of overall drug metabolism compared with hepatic enzymes.

Option d: 'Drug metabolism enzymes usually convert hydrophilic drugs to more hydrophobic metabolites.' This is false. The main goal of metabolism is to increase hydrophilicity (water solubility) to enhance excretion; many metabolic reactions (especially Phase I oxidation/reduction and Phase II conjugation) convert lipophilic (hydrophobic) compounds into more polar, hydrophilic metabolites for easier elimination. Therefore, this statement reverses the actual direction of polarity change.

In summary, option b accurately states a core function of drug metabolizing enzymes—contributing to the clearance of many drug molecules from the plasma—whereas the other options contain factual inaccuracies about enzyme location, phase classification, or the hydrophilicity/properties of metabolites.

PHR1022 S2 2025 PA Practice Test for progress test 1

Which of the following statements about metabolism is TRUE:

查看解析

登录即可查看完整答案

类似问题

Cyclophosphamide must be activated by which organ before it can cause crosslinks between DNA strands?

Which of the following statements about metabolism is TRUE:[Fill in the blank]

How does the enzyme CYP3A4 contribute to drug metabolism?[Fill in the blank]

If a prodrug is converted into its bioactive form through metabolism by a cytochrome P450 enzyme then:

Which is primarily responsible for pharmacologic metabolism?

The liver has an important role in drug ADME. Which ONE of the following is CORRECT?

Where are lidocaine, mepivacaine, and bupivacaine metabolized?

更多留学生实用工具

考试浏览器助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单