36 Questions
What is the primary function of biotransformation in an organism?
To enhance the elimination and detoxification of chemicals
What is the result of Phase I metabolism in xenobiotic metabolism?
Increased excretability of metabolites
What is the primary location of biotransformation reactions within the cell?
Cytoplasm
What is the effect of storage on the body's ability to biotransform and eliminate toxicants?
It affects the body's ability to biotransform and eliminate toxicants
What is the term for the 'build-up' process of biochemical reactions in metabolism?
Anabolism
What is the primary purpose of Phase II metabolism in xenobiotic metabolism?
To increase the excretability of metabolites
What is the result of biotransformation on the fate of lipophilic compounds in the body?
They become more hydrophilic
What is the term for the process of converting chemicals to less toxic forms in biotransformation?
Detoxification
What is the primary route of elimination of hydrophilic metabolites in the body?
Kidneys
What is the primary goal of the detoxification process?
To convert toxicants into more water-soluble forms
What is the main site of biotransformation in the body?
Liver
What is the result of Phase I reactions in biotransformation?
Increase in hydrophilicity
What is the purpose of biotransformation in the body?
To terminate the biological activity of chemicals
What is the result of some chemicals being partially converted to more toxic products?
Increased toxicity of the parent substance
What is the role of cytochrome P450 in biotransformation?
To add or unmask reactive side groups
What is the primary mechanism for eliminating toxicants from the body?
Excretion through urine and feces
What is the result of Phase II reactions in biotransformation?
Conjugation of reactive side groups
What is the main organ responsible for the elimination of toxicants through excretion?
Kidney
What is the primary effect of the oxidation reaction in Phase I metabolism?
Addition of oxygen and removal of hydrogen
What is the role of the enzyme alcohol dehydrogenase in Phase I metabolism?
To catalyze oxidation reactions
What is the effect of CYP450 enzyme induction on the metabolism of toxicants?
It increases the bioactivation of toxicants
What is the primary function of the P450 system in Phase I metabolism?
To bioactivate non-toxic compounds
What is the role of glutathione in the metabolism of paracetamol?
To conjugate with the reactive metabolite NAPQI
What is the effect of a paracetamol overdose on the metabolism of NAPQI?
Conjugation with glutathione becomes saturated, leading to increased hepatocyte damage
What is the effect of CYP450 enzyme induction on the composition of P450 enzymes?
It causes a marked increase (>20-fold) in the composition of P450 enzymes
What is the role of esterases in Phase I metabolism?
To catalyze hydrolysis reactions
What is the effect of rifampin on the expression of CYP450 enzymes?
It induces the expression of CYP3A
What is the effect of induction on the therapeutic effect of drugs?
It decreases the therapeutic effect of drugs
What is the role of P450 in biotransformation?
It is a phase I reaction enzyme that can be induced by toxicants
What is the effect of conjugation reactions on molecular size and polarity?
It increases molecular size and polarity
What is the role of CYP2E1 in the metabolism of vinyl chloride?
It converts vinyl chloride to chloroethylene oxide
What is the effect of chronic low-level exposure to aflatoxins?
It increases the risk of liver cancer
How does oltipraz prevent AFB1 toxicity?
It inhibits CYP450 and induces GST
What is the result of biotransformation reactions?
It increases the polarity of compounds and decreases toxicity via metabolism of a toxic parent compound
What is the role of CYP3A4 in the metabolism of aflatoxin B1?
It bioactivates aflatoxin B1 to its epoxide form
What is the effect of induction on tolerance to toxicants?
It increases tolerance to some toxicants while enhancing the toxicity of others
This quiz covers the biotransformation of toxicants in the body, including the processes of anabolism and catabolism, and how storage affects the body's ability to eliminate toxic substances. It also explores how biotransformation has evolved to deal with metabolites and naturally occurring toxicants. Test your knowledge of this important topic in toxicology!
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
