Showing posts with label MCQ's in Toxicology. Show all posts
Showing posts with label MCQ's in Toxicology. Show all posts
Saturday, 4 August 2018
Monday, 2 July 2018
PK Gupta Series 12: Toxicology- MCQ
 |
| PK Gupta Toxicologist |
Series 12: Toxicology- MCQ
Multiple choice questions (choose the best
statement)
Exercise
Q.1. Toxicants are most likely to
be reabsorbed after being filtered at the glomerulus are ---
a)
organic anions
b)organiccations
c) natural polar molecules
d) highly lipid- soluble molecules
Q.2. A high urinary pH would favor
the excretion of ---
a) organic acids
b) organic bases
c) neutral organic compounds
d) none of the above
Q.3. Diuretics can enhance the
renal elimination of compounds that ---
a) are of molecular weight greater
than 70 kDa
b) are ions trapped in the tubular
lumen
c) are highly lipid soluble
d) are highly protein bound
Q.2. The amount of a volatile
liquid excreted by the lungs is ------------------
a) inversely proportional to its
lipid-water partition coefficient
b) directly proportional to its
vapour pressure
c) directly proportional to its
molecular weight
d) inversely proportionate to
cardiac output
Q.5. Kernicterus results from ---
a) enzyme induction leading to
decreased glucocorticoid levels
b) excess ingestion of foods containing
tyramine
c) displacement of bilirubin from
plasma proteins
d) malabsorption of fat-soluble
vitamins
Q.6. All of the following could
influence the gastrointestinal absorption of xenobiotics except ---.
a) pH
b) intestinal microflora
c) presence of food
d) time of day
Q.7. The rate of diffusion of a
xenobiotic across the GI tract is proportional to all of the following except
---
a)
hepatic blood flow
b) surface area
c) permeability
d) residence time
Q.8. Which of the following is not
absorbed in the colon?
a) water
b) sodium ion
c) glucose
d) hydrogen ion
Q.9. Nanoparticles are considered
to have diameter smaller than ----
a) 100 µm
b) 10 µm
c) 1 µm
d) 0.1 µm
Q.10. All of the following are true
of nanoparticles except ---
a) they are capable of exposing the
lung to a large number of particles
b) they are capable of exposing the
lung to a large particle surface area.
c) because of turbulence, very few
reach the alveoli
d) they are the focus of recent
toxicologic research
Answers
1. d; 2. a; 3.b
; 2. b; 5. c; 6.d ; 7.a ; 8.c
; 9. d; 10. c;
Exercise
Q.1. All of the following are
significantly stored in bone matrix except ----
a) lead
b) diquat
c) strontium
d) fluoride
Q.2. All of the following can cross
the placenta except ---
a) heparin
b) rubella virus
c) spirochetes
d) IGG antibody
Q.3. Methylmercury crosses the
blood-brain barrier by combining with cysteine and forming a molecular similar
to ---
a) glycine
b) glutamine
c) taurine
d) methionine
Q.2. Which of the following statements
are true?
a) the blood-brain barrier of a
70-year old is more permeable than that of a premature infant
b) chemicals/ drugs can be excreted
into the urine by active secretion
c) the kidney lacks cytochrome P450
enzymes.
d) all mammalian placentas have the
same number of tissue layers
Q.5. All of the following are true
of breast milk except --
a) acidic compounds may be more
concentrated in milk than plasma
b) toxicants can be passed from
mother to offspring.
c) toxicants can be passed from
cows to humans
d ) DDT, PCBs, and PBBs can be
found in human milk
Q.6. Active transport is
characterized by all of the following except ---
a)
a movement against a concentration gradient
b) energy requirement
c) nonsaturability
d) competitive inhibition
Q.7. All of the following are true
of the facilitated diffusion except ---.
a) does not require energy
b) movement against a concentration
gradient
c) saturability
d) involvement of a carrier
Q.8.
Which of the following does NOT uncouple oxidative phosphorylation?
a) pentachlorophenol
b) dinitrophenol
c) aconitase
d) salicylate
e) gramacidin
a) pentachlorophenol
b) dinitrophenol
c) aconitase
d) salicylate
e) gramacidin
Q.9.
Which of the following is NOT true regarding peroxisome proliferators?
a)
they are a structurally diverse group of chemicals
b) they cause marked induction of lipid metabolizing enzymes
c) they often are non-genotoxic hepatocarcinogens in rodents
d) they induce hepatic CYP1A which is indicative of peroxisome proliferation
e) they operate via the peroxisome proliferator activated receptor
b) they cause marked induction of lipid metabolizing enzymes
c) they often are non-genotoxic hepatocarcinogens in rodents
d) they induce hepatic CYP1A which is indicative of peroxisome proliferation
e) they operate via the peroxisome proliferator activated receptor
Q.10 For which of the following
route of exposure, pre-systemic elimination is possible?
a. Oral (GIT)
b. Inhalation
c. Intramuscular
d. Intravenous
Answers
1. 1. b; 2.
a; 3.d ; 2.b ; 5. a; 6. c; 7.
b; 8. c; 9. d; 10. a.
Exercise
Q 1. Methylation ---
a)
typically increases the water solubility of xenobiotics
b) is a major pathway of xenobiotic metabolism
c) requires S-adenosylmethionine (SAM)
d) requires acetyl coenzyme A
e) requires taurine
b) is a major pathway of xenobiotic metabolism
c) requires S-adenosylmethionine (SAM)
d) requires acetyl coenzyme A
e) requires taurine
Q.2.
Of the more than 40 cytochrome P450 isozymes, which 6 account for the majority
of xenobiotic metabolism in humans?
a)
CYP1E1, CYP2B1, CYP2B19, CYP2F1, CYP3A7, CYP4A6
b) CYP1A1, CYP2A6, CYP2B6, CYP2D6, CYP2F2, CYP4B2
c) CYP1B2, CYP2C6, CYP2F2, CYP3A2, CYP3A4, CYP4A2
d) CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4
e) CYP1A1, CYP2C8, CYP2F2, CYP3A7, CYP4A2, CYP4A6
b) CYP1A1, CYP2A6, CYP2B6, CYP2D6, CYP2F2, CYP4B2
c) CYP1B2, CYP2C6, CYP2F2, CYP3A2, CYP3A4, CYP4A2
d) CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4
e) CYP1A1, CYP2C8, CYP2F2, CYP3A7, CYP4A2, CYP4A6
Q3.
Which of the following is NOT a characteristic of active transport?
a) blocked by saxitoxin
b) movement against a concentration gradient
c) exhibits a transport maximum
d) energy dependent
e) selectivity
a) blocked by saxitoxin
b) movement against a concentration gradient
c) exhibits a transport maximum
d) energy dependent
e) selectivity
Q.2.
Which of the following does NOT inhibit electron transport?
a) rotenone
b) succinate
c) antimycin-A
d) formate
e) azide
a) rotenone
b) succinate
c) antimycin-A
d) formate
e) azide
Q.5.
Reabsorption of toxicants does NOT occur through
a)
entero-hepatic recirculation
b) glomerular filtration
c) diffusion
d) active transport
e) carriers for physiologic oxyanions
b) glomerular filtration
c) diffusion
d) active transport
e) carriers for physiologic oxyanions
Q.
6. When all receptors are occupied by a toxicant and there is a miximum amount
of receptor-toxicant complexes, the response is labelled -------.
a)
t1/2
b)LCmax
c)
Emax
d)Cmax
Q.7. Which of the following statements is true?
a)
toxicant receptor interactions are always reversible
b)
receptors for toxicants are always enzymes
c)
the toxic response is relsayted to the toxicant concentration in the plasma
more so than the concentration at the site of action.
d)
none of the above
Q.8. An increase in free drug concentration will
----.
a)
increase the pharmacological effect
b) decrease the toxic effect
c) decrease the amount of drug
filtered at the glomerulus
d) none of the above
Q.9. The phrase that best defines "toxicodynamics"
is the
a) linkage between exposure and dose
b) linkage between dose and response
c) dynamic nature of toxic effects among various species
d) dose range between desired biological effects and adverse health effects
e) loss of dynamic hearing range due to a toxic exposure
a) linkage between exposure and dose
b) linkage between dose and response
c) dynamic nature of toxic effects among various species
d) dose range between desired biological effects and adverse health effects
e) loss of dynamic hearing range due to a toxic exposure
Q. 10. Which of the following is NOT an initiating event in
carcinogenesis?
a) DNA adduct formation
b) DNA strand breakage
c) mutation of proto-oncogenes
d) oxidative damage of DNA
e) mitogenesis
a) DNA adduct formation
b) DNA strand breakage
c) mutation of proto-oncogenes
d) oxidative damage of DNA
e) mitogenesis
Answers
1.c;
2.d; 3.a; 2.b; 5.b; 6. c; 7. d; 8. a;
9.b; 10. e.
Exercise
Q.1. A probe drug for human CYP2C19
activity is -----
a) mephenytoin
b) valproic acid
c) carbamazepine
d) warfarin
Q. 2. All of the following are true
CYP2D6 except ----------
a) it converts codeine to morphine
b) it is polymorphic
c) it is induced by quinidine
d) poor metabolizers have a lower
risk of lug cancer
Q. 3. Aryl hydrocarbon receptor
agonist include all of the following except---
a) TCDD
b) benzopyrene
c) 3- methylcholanthrene
d) benzene
Q. 2. Enzyme induction in humans
has been associated wit ---
a) osteomalacia
b) hepatocellular carcinoma
c) cirrhosis
d) psoriasis
Q. 5. In metabolism-dependent
inhibition of cytochrome P45o, ---
a) the parent compound is a potent
inhibitor.
b) the metabolite must be a product
of P450 catalysis
c) the metabolite is a potent
inhibitor
d) the inhibition is always
irreversible
Q. 6. A compound that induces CYP2D6 is
------------
a) rifampin
b) dexamethazone
c) ethanol
d) none of the above
Q. 7. All of the following are
considered phase I biotransformation reactions except ---
a) hydrolysis
b)conjugation
c) reduction
d) oxidation
Q. 8. All of the following
statements are true except--------------
a) forms of epoxide hydrolase can
exist in both microsomes and cytosol
b) gemfibrozil is conjugated with
glucuronic acid before it is oxidized by cytochrome P 50
c) CYP2D6 and CYP2C9 metabolize
over half of the drugs in current use
d) biotransformation can take place
in the gut
Q. 9. UDP glucuronyltransferases
conjugate all of the following endogenous molecules except ------------------
a) thyroid hormone
b) bilirubin
c) steroid hormones
d) parathyroid hormone
Q. 10. Id codeine were given to a
patient who was a 2D6 ultrametabolizer, the most likely result would be
---------
a) inadequate analgesia
b) higher-than-normal levels of
morphine at 2 hr post-dose
c) higher-than-normal levels of
codeine at 4 hr post-dose
d) higher-than-normal levels of
oxycodone at 4 hr post-dose
Answers
1.
a;
2. c; 3. d; 2 a ; 5. c; 6. d; 7, b; 8. c; 9. d; 10. b.
Exercise
Q. 1. Victim drug is
----------------
a) a drug whose clearance is
determined mostly by a single route of administration
b) a drug that induces neutralizing
antibodies
c) a drug that is unstable in
plasma
d) a racemic drug mixture where one
isomer inhibits the metabolism of the other isomer.
Q. 2. Terfenadine and ketoconazole
are examples of -----------
a) enzyme inducers
b) perpetrator and inhibitor
c) victim drug and perpetrator
d) drugs with limited
biotransformation
Q. 3. All of the following are true
except ----------------------
a) hyperforin induces CYP3A4
b) broccoli inhibits 1A2
c) grapefruit juice inhibits
intestinal CYP3A4
d) drugs that inhibits transporters
can help anticancer agents
Q. 2. Levels of UDPGA and PAPS are
lowered by --------------
a) Saint-John’s- wort
b) phenobarbital
c) rifampin
d) fasting
Q. 5. An example of a pair of
enantiomers in which one inhibits CYP2D6
and the other has little inhibiting activity is ---------
a) R and S methadone
b) R and S warfarin
c) R and S mephenytoin
d) quinidine and quinine
Q. 6. Which of the following
biotransformation enzyme-subcellular location pairs is correct?
a) alkaline phosphatase-cell
membrane
b) carboxylesterase-blood
c) sulfotransferase-cytosol
d) all of the above
Q. 7. The least likely
biotransformation reaction that aniline would undergo is -----------
a) halogenation
b) aromatic hydroxylation
c) N-acetylation
d) N-glucuronidation
Q. 8. The proteins KEAPI and Nrf2
----
a) suppress CYP expression in response
to inflammation
b) induce enzymes in response to
oxidative stress
c) promote DNA methylations
d) none of the above
Q. 9. All of the following are true
to glutathione except----
a) Germ cells and ovum have high
levels
b) conjugation of dibromoethane
results in a mutagenic metabolite
c) conjugation of electrophiles is
a major means of protecting DNA
d) conjugation always occurs
enzymatically
Q. 10. Phenobarbital ----------
a) cause liver tumors in human and
rodents
b)
cause liver tumors in rodents but not humans
c) cause liver tumors in primates
but not in rodents
d) cause liver tumors in rodents
and nasal tumors in humans
Answers
1.
a;
2. c; 3. b; 2. d; 5. d; 6. d; 7, a; 8. b; 9. d; 10. b .
Exercise
Q. 1. Systemic availability of an
orally administered toxicant is dependent on ---
a)
gastrointestinal absorption
b) intestinal mucosa metabolism
c) first-pass liver metabolism
d) all of the above
Q. 2. Which of the following
statements are true ------------
a)
renal clearance is equal to urine formation
b) hepatic clearance cannot exceed
hepatic blood flow
c) a process that increases free
drug concentration will decrease hepatic clearance and increase renal clearance
d) total body clearance equals dose
divided by half-life
Q. 3. A classic example of a drug
inducing its own metabolism is --
a) warfarin
b) lovastatin
c) carbamazepine
d) theophylline
Q. 2. An example of a thermodynamic
parameter used in physiologic,
Toxicokinetic models is ----
a) tissue partition co-efficient
b) alveolar ventricular rate
c) cardiac output
d) liver volume
Q. 5. Fick/s law of diffusion
a) is a zero-order process
b) is a first-order process
c) applies to active transport
d) requires energy
Q. 6. The method of predicting the
toxicokinetic behavior of chemicals and drugs across species is called
-----------------
a) Monte Carlo stimulation
b) benchmark kinetics
c) allometric scaling
d) linear regression kinetics
Q. 7. Which of the following is not
theoretically possible?
a) volume of distribution greater
than volume of human body
b) volume of distribution equal to
blood volume
c)total clearance equal to renal
clearance
d) bioavailability (F) greater than
1
Q. 8. A compartment in which uptake
of xenobiotic is dependent on membrane permeability and total membrane area is
called -------------
a) perfusion limited
b) diffusion limited
c) blood flow limited
d)
ventilation limited
Q. 9. The alpha phase of an
intravenously administered drug classically represents the ------------
a) absorption phase
b) elimination phase
c) dissolution phase
d) distribution phase
Q. 10. An advantage of a
physiologic, toxicokinetic model over a classic model is ------------
a) it may be able tp predict tissue
concentration
b) it only has 2 compartments
c)
the mathematics are less complicated
d) it can give a better estimation
of bioavailability
Answers
1.
d;
2. b ; 3.c ; 2.a ; 5. b; 6.c ; 7, d; 8. b; 9. d; 10. a .
Exercise
Q. 1 the hepatic clearance of a
drug with a high hepatic extraction ratio is largely dependent on ------
a) drug protein binding
b) hepatic blood flow
c) drug-metabolizing enzyme
activity
d) intestinal blood flow
Q. 2. All of the following are true
of saturation kinetics with increasing dose except --------
a) clearance must decrease
b) half-life can increase or
decrease
c) volume of distribution will
decrease if there is saturation of serum protein binding
d) volume of distribution will
decrease if there is saturation of tissue binding
Q. 3. All of the following are true
of nonlinear kinetics except ----------
a) ratio of metabolites will remain
constant with change in dose
b) clearance will change with
change in dose
c) AUC will not be dose
proportional
d) decline of xenobiotic is non
exponential
Q. 2. All of the following are true
of first-order kinetics except ----
a) steady state concentration is
proportional to rate of intake
b) rate of intake will not change
time to steady state
c) half-life is inversely
proportional to clearance
d) a change in half-life will not
change time to steady state
Q. 5. All of the following are true
of first-order kinetics except -------------
a) the elimination rate constant
increases with dose.
b) a semilogarithmic plot of plasma
concentration versus time yields a single straight line
c) the concentration of xenobiotic
in plasma decreases by a constant fraction per unit time
d) the volume of distribution in
independent of dose
Q. 6. After ------. 93.8% of a dose
of drug is eliminated
a) 3 half-lives
b) 4 half-lives
c) 5 half-lives
d) 6 half-lives
Q. 7 all of the following are
components of the central compartment except ------------------.
a) liver
b) lungs
c) bone
d) kidney
Q. 8. Which of the following has
the largest value of distribution
a) chloroquine
b) ethyl alcohol
c) albumin
d) ethylene glycol
Q. 9. The common units used to
express total clearance of a toxicant are ----
a) mg/mL
b) mg/min
c) mL/ min
d) mg/min.mL
Q. 10. In first order kinetics
----------------------
a) a constant amount of toxicant is
removed oer unit time
b) AUC is not proportional to dose
c) half-life changes with increasing
dose
d) clearance, volume of
distribution, and half-life do not change with dose
Answers
1.
b;
2. c; 3. a; 2. d; 5. a; 6. b; 7, c; 8. a; 9.c ; 10. d .
