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| Prof PK Gupta Founder and Editor-in-Chief "Toxicology International" |
PK Gupta Series 16: Toxicology (MCQs)
Introduction
This series cover a range of core toxicological areas, including principles of toxicity, metals, micronutrients, poisonous organisms, pesticides, radioactive materials and poisonous plants, target organ, non-target organ toxicity, etc. Each section is supplemented with practical exercises to support active learning. This will help readers gain a deeper understanding of toxicology.
Exercise
Q.1. amphipathic xenobiotics that can become trapped in lysosomes and cause phospholipidosis include all of the following except ------.
a) ethylene glycol
b) amiodarone
c) amitriptyline
d) fluoxetine
Q.2. which of the following parent toxicant-electrophilic metabolite pairs is incorrect?
a) halothane - phosgene
b) bromobenzene - bromobenzene 3, 4 oxide
c) benzene – muconic aldehyde
d) allyl alcohol - acrolein
Q.3. all of the following are capable of accepting the electrons from reductases and forming radicals except ----------
a) paraquat
b) doxorubicin
c) n-hexane
d) nitrofurantoin
Q.4. an example of the formation of an electrophilic toxicant from an inorganic chemical is -
a) CO to CO2
b) AsO4
c) NO to NO2
d) hydroxide ion to water
Q.3. the general mechanism for detoxification of electrophiles is -----
a) conjugation with glucuronic acid
b) conjugation with acetyl CoA
c) conjugation with glutathione
d) conjugation with sulphate
Q.6. the most common nucleophilic detoxification reaction that amines undergo is ----
a) acetylation
b) sulfation
c) methylation
d) amino acid conjugation
Q.7. detoxification mechanisms fail because ------
a) toxicants may over helm the detoxification process
b) a reactive toxicant may inactivate a detoxicating enzyme.
c) detoxication may produce toxic by-product
d) all of the above
Q.8. the most potent carcinogen derived from nicotine is ----.
a) naphthene
b) styrene
c) nicotine-derived nitrosamine ketone (NNK)
d) meth tert-butyl ketone
Q.9. hydroxyl radical can be produced by all of the following except ----
a) the action of nitric oxide synthetase on water
b) interaction of ionizing radiation and water
c) reductive homolytic fission of hydrogen peroxide
d) interaction of silica with surface iron ions in lung tissue
Q.10. if an electrophile is covalently bound to a protein that does not play a critical function, the result is considered a -----.
a) toxication reaction
b) detoxication reaction
c) MNA adduct formation
d) Fenton reaction
Answers
1.a; 2. a; 3. c; 4. b; 3. c; 6. a; 7. d; 8. c; 9.a ; 10. b;
Exercise
Q. 1 which of the following receptor-exogenous ligand pairs is incorrect?
a) estrogen receptor-- zearalenone
b) glucocorticoid receptor -- dexamethsasone
c) aryl hydrocarbon receptor --rifampicin
d) peroxisome proliferator activated receptor -- clofibrate
Q.2. which of the following receptor-agonist pairs incorrect?
a) glutamate receptor --kainate
b) glycine receptor –strychnine
c) GABA (A) receptor --muscimol
d) opioid receptor -- meperidine
Q.3. which of the following receptor- antagonist pairs is incorrect
a) adrenergic beta I receptor- metopronol
b) serotonin (2) receptor –ketanserin
c) glutamate receptor --ketamine
d) GABA (A) receptor-- avermectins
Q.4. clonidine overdose mimics poisoning with ---
a) morphine
b) cocaine
c) phencyclidine
d) amphetamine
Q.3. all of the following act as inhibitors of the citric acid cycle except ---
a) 4- pentenoic acid
b) fluoroaceate
c) DCVC (S-(1,2-dichlorovinyl)-L-cysteine)
d) malonate
Q.6. all of the following are inhibitors of ADP phosphorylation except ---
a) oligomycin
b) DDT
c)ethanol
d) N-ethylmaleimide
Q.7. all of the following cause calcium influx into the cytoplasm except ----
a) capsaicin
b) formate
c)domoate
d) amphotericin B
Q.8. all of the following inhibit calcium export from the cyptoplasm except ---
a) vanadate
b) methyl mercury
c) bromobenzene
d) carbon tetrachloride
Q.9. hydroxyl radical is enzymatically detoxified by ---
a) catalase
b) glutathione peroxide
c) glutathione reductase
d) none of the above
Q.10. which of the following regarding cell death is true
a) necrosis requires ATP
b) release of cytochrome c usually triggers necrosis
c) toxicants at low doses usually cause apoptosis and necrosis at higher doses
d) apoptosis is never a desirable effect
Answers
1.c; 2.b ; 3.d ; 4.a ; 3.a ; 6.c ; 7. b; 8.b ; 9.d ; 10. c;
Exercise
Q.1. major target molecules for toxicants include all of the following except ----
a) proteins
b) vitamins
c) DNA
d) lipids
Q.2. all of the following toxins act by enzymatic reaction except ---
a) ricin
b) anthrax
c) tetrodotoxin
d) botulinum
Q.3. apoptotic pathways can be initiated by -----
a) DNA damage
b) mitochondrial insult
c) death-receptor stimulation
d) all of the above
Q.4. the enzyme that repairs oxidized protein thiols is called -------
a) HMG- coenzyme A reductase
b) adenyl cyclase
c) phospholipase
d) none of the above
Q.3. the mechanism of action for bleomycin-induced lung injury is presumed to include -----
a) DNA-adduct formation
b) generation of reactive oxygen species
c) inhibition of cytochrome oxidase
d) none of the above
Q.6. all of the following are true of oxidative DNA damage except ---
a) mitochondrial DNA is much more resistant to damage that nuclear DNA
b) B-hydroxy-deoxyguanosine in the urine is a marker
c) it can lead to base pair transversions
d) it can lead to a point mutation
Q.7. an example of denatured protein is --
a) Golgi complex
b) micronuclei
c)Heinz body
d) histone
Q.8. an important feature of lipid peroxidation is ---
a) it cannot be blocked by antioxidants
b) damage can be propagated in a chain reaction-like manner
c) it never involves the Fenton reaction
d) the end products are different from the end products of the reaction of lipids with ozone
Q.9. all of the following are true regarding mechanisms of immune system toxicology except ---
a) TCDD induced thymic atrophy may be mediated by the aryl hydrocarbon receptor
b) the addition of a happen to a protein may cause a conformational change that displays previously hidden antigenic regions
c) oral exposure of a xenobiotic is associated with a much greater chance of an immune reaction than by other routes.
d) the “danger hypothesis” refers to a break in immune tolerance to an antigen triggered by signals initiated by cellular or systemic stress.
Q.10. which statement is true regarding the PPAR alpha-receptor
a) stimulation causes peroxisome proliferation in humans
b) they are present in adipose tissues
c) they are involved in fatty acid beta-oxidation
d) thiazolidinediones act as ligands
Answers
1, b; 2. c ; 3.d ; 4. d; 3.b ; 6.a ; 7.c ; 8.b ; 9.c ; 10. c.
FURTHER READING
Gupta PK (2016) Fundamentals of Toxicology: Essential concepts and applications. 1st Edition. ISBN-9780128054260, pp 438, BSP/Elsevier, USA https://www.elsevier.com/books/fundamentals-of-toxicology/.../978-0-12-805426-0
Gupta PK (2018) Illustrative Toxicology with Question bank. 1st Edition. Elsevier, USA pp 640 https://www.elsevier.com/books/illustrated-toxicology/gupta/978-0-12-813213-5
Gupta PK (2018) Toxicology: Resource for Self-Study Questions: Ist Ed pp550 Published by All Solutions You Need: www. http://allsolutionsyouneed.blogspot.com, Kinder direct publications: Amazon.com https://www.amazon.com/TOXICOLOGY-Resource-Self-Study...ebook/.../B07DDFW...
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