Top Hat Exam 1

Question 1

Which of the following statements BEST characterizes synergism?
a Synergism occurs if two chemicals with a similar action, when given together, produce an effect that is greater in magnitude than the sum of the effects when the chemicals are given individually
b Synergism occurs if a xenobiotic that lacks an effect of its own increases the effect of a second, active xenobiotic
c Synergism occurs if two chemicals with the same effect, when given together, produce an effect that is equal in magnitude to the sum of the effects with the chemicals are given individually
d Synergism occurs if two drugs with the same effect, when given together, produce an effect that is equal in magnitude to the effect of only one of the drugs given individually

Answer 1

a Synergism occurs if two chemicals with a similar action, when given together, produce an effect that is greater in magnitude than the sum of the effects when the chemicals are given individually

Question 2

Toxicants may move across biological membranes by all of the following mechanisms EXCEPT:
 a Aqueous diffusion
 b Aqueous hydrolysis
 c Lipid diffusion
 d Special carrier transport

Answer 2

b Aqueous hydrolysis

Question 3

Toxicology may be defined as the study of:
a The degradation of biological warfare agents
b The cost of toxicity testing
c The adverse effects of chemicals in living systems
d The regulation of chemicals in the home

Answer 3

c The adverse effects of chemicals in living systems

Question 4

Which of the following reactions is NOT considered a phase II biotransformation?
 a Glucuronidation
 b Acetylation
 c Sulfation
 d Epoxide hydration

Answer 4

d Epoxide hydration

Question 5

The environmental matrices/pathways indicated in our EHS model include all of the following EXCEPT:
 a Soil
 b Food
 c Water
 d Air
 e Surfaces
 f All of the above are matrices

Answer 5

f All of the above are matrices

Question 6

Paracelsus was an expert in all of the following professions EXCEPT:
 a Alchemist
 b Physician
 c General Occultist
 d Astrophysicist

Answer 6

d Astrophysicist

Question 7

The interaction of chemicals in TOXICOLOGY includes all of the following except:
 a Synergistic
 b Additive
 c Potentiation
 d Subtractive
 e Antagonistic

Answer 7

d Subtractive

Question 8

Regarding allometric scaling of doses across species, which species is placed incorrectly in the hierarchy:
 a Human
 b Monkey
 c Dog
 d Cat
 e Rabbit
 f Guinea pig
 g Rat
 h Mouse

Answer 8

b Monkey

Question 9

Biotransformation reactions generally produce a product that is:
a more likely to be distributed intracellularly
b more likely to produce unwanted effects
c less lipid-soluble than the original chemical
d more lipid-soluble than the original chemical

Answer 9

c less lipid-soluble than the original chemical

Question 10

A toxicant’s distribution to a specific tissue does NOT
a Depend on blood flow and the size of the organ
b Depend on the solubility of the chemical in that tissue
c Depend on the concentration gradient between blood and tissue
d Increase for xenobiotics that are bound to plasma proteins

Answer 10

d Increase for xenobiotics that are bound to plasma proteins

Question 11

High-energy cofactors that are NOT involved in phase II reactions include:
a UDP-glucuronic acid
b S-adenosylmethionine
c Phosphoadenosine phosphosulfate
d Amino acids such as taurine and glycine

Answer 11

d Amino acids such as taurine and glycine

Question 12

Now that you know that all chemicals are toxic, which of the following corollary statements is FALSE?
a It is the dose that determines a remedy from a poison
b Exposure limits may be set for all chemicals that will instill confidence that we are safe from chemicals
c We cannot maintain our standard of living without exposure to chemicals
d Life begins with perfect chemistry.

Answer 12

b Exposure limits may be set for all chemicals that will instill confidence that we are safe from chemicals

Question 13

Toxicology testing in the 21st century will include in silico testing of chemicals. Advantages are numerous when compared with standard bioassays, but some problems still need to be worked out. These problems include:
a Cheaper and high throughput
b Predictive analyses, more informative, and efficient
c Minimize animal testing and focus on relevant dose levels
d Human cells- minimal interspecies extrapolation

Answer 13

b Predictive analyses, more informative, and efficient

Question 14

Pesticides are ubiquitous and present to the environment in a diversity of 900 ingredients composing 35,000 commercial products with billions of pounds being released to the global environment annually.
a True
b False

Answer 14

a True

Question 15

Which type of pesticide inhibits the acetylcholinesterase enzyme and with chronic exposure may results in a neuropathy characterized by weakness or paralysis of the arms and legs?
 a Organophosphates
 b Organochlorines
 c Pyrethroids
 d Plant Incorporated-protectants (PIPs)
 e None of the above fit the description

Answer 15

a Organophosphates

Question 16

Which chemical formed as a by-product in the production of herbicides such as “agent orange” has been linked to Parkinson’s Disease, Ischemic Heart Disease and Hairy-cell leukemia also produces chloracne and was used in the deliberate poisoning of Ukrainian President Victor Yushchenko?
 a Polychlorinated biphenyls (PCBs)
 b Dioxin (TCDD)
 c Asbestos
 d Lead
 e Mercury

Answer 16

b Dioxin (TCDD)

Question 17

Which of the following statements is false?
a Glucuronide conjugates are excreted readily by the kidneys
b A lipid-soluble xenobiotic metabolite will sequester in fatty tissue
c Acidification of the urine may help trap acidic drugs in urine
d For a weakly acidic drug (pKa=3) at equilibrium, the ratio of nonionized to ionized drug (HA/A-) equals 1 when the pH of the medium is 3.

Answer 17

c Acidification of the urine may help trap acidic drugs in urine

Question 18

Induction of xenobiotic biotransformation by exposure to a toxicant will:
a Result in irreversible changes in enzyme activity
b Result in increased amounts of enzymes in the endoplasmic reticulum
c Results in decreased amounts of enzymes in the nucleus
d Require 3 to 4 months to reach completion

Answer 18

b Result in increased amounts of enzymes in the endoplasmic reticulum