Toxicology midterm

Question 1

Deithylstilbestrol (DES) exposure:

Answer 1

Increases the risk of clear cell adenocarcinoma of the vagina

Question 2

Early (prenatal) exposure to which of the following teratogens is most often characterized by craniofacial dysmorphism?

Answer 2

Ethanol

Question 3

The nervous system is derived from which of the following germ layers?

Answer 3

Ectoderm

Question 4

Toxin exposure during which of the following periods is likely to have the LEAST toxic effect on the developing fetus?
a. gastrulation.
b. organogenesis.
c. preimplantation.
d. third trimester.
e. first trimester.

Answer 4

c. Preimplantation

Question 5

Regarding prenatal teratogen exposure, which of the following statements is FALSE?
a. Major effects include growth retardation and malformations.
b. Exposure to teratogens during critical developmental periods will have more severe effects on the fetus.
c. There is considered to be a toxin level threshold below which the fetus is capable of repairing itself.
d. The immune system of the fetus is primitive, so the fetus has little to no ability to fight off chemicals and repair itself.
e. Embryo lethality becomes more likely as the toxic dose is increased.

Answer 5

d. The immune system of the fetus is primitive, so the fetus has little to no ability to fight off chemicals and repair itself

Question 6

Which of the following stages of the cell cycle are important in monitoring DNA damage and inhibiting progression of the cell cycle?

Answer 6

G1-S, S, G2-M

Question 7

Which of the following molecules is NOT important in determining the ultimate outcome of embryonal DNA damage?
a. p53.
b. Bax.
c. Bcl-2.
d. c-Myc.
e. NF- κB.

Answer 7

e. NF- κB

Question 8

Which of the following is NOT a physiologic response to pregnancy?
a. increased cardiac output.
b. increased blood volume.
c. increased peripheral vascular resistance.
d. decreased plasma proteins.
e. increased extracellular space.

Answer 8

c. Increased peripheral vascular resistance

Question 9

All of the following statements are true EXCEPT:
a. Offspring of white mothers have a higher incidence of cleft lip or palate than do black mothers, after adjusting for paternal race.
b. Cytomegalovirus (CMV) is a common viral cause of birth defects.
c. Folate supplementation during pregnancy decreases the risk of neural tube defects.
d. Cigarette smoke and ethanol are both toxic to the placenta.
e. In humans, there is a negative correlation between stress and low birth weight.

Answer 9

e. In humans, there is a negative correlation between stress and low birth weight

Question 10

Which of the following is NOT a mechanism involving the endocrine system by which chemicals induce developmental toxicity?
a. acting as steroid hormone receptor ligands.
b. disrupting normal function of steroid hormone metabolizing enzymes
c. disturbing the release of hormones from the hypothalamus.
d. disturbing the release of hormones from the pituitary gland.
e. elimination of natural hormones.

Answer 10

e. Elimination of natural hormones

Question 11

Which of the following cell types secretes anti-Müllerian hormone (AMH)?

Answer 11

Sertoli cell

Question 12

Penile erections are dependent on

Answer 12

Corpora cavernosa smooth muscle relaxation

Question 13

The corpus luteum is responsible for the secretion of which of the following hormones during the first part of pregnancy?

Answer 13

1. Progesterone
2. Estradiol

Question 14

All of the following statements regarding the hypothalamo-pituitary-gonadal axis are true EXCEPT:
a. FSH increases testosterone production by the Leydig cells.
b. FSH and LH are synthesized in the anterior pituitary.
c. Estradiol provides negative feedback on the hypothalamus and the anterior pituitary.
d. GnRH from the hypothalamus increases FSH and LH release from the anterior pituitary.
e. The LH spike during the menstrual cycle is responsible for ovulation.

Answer 14

a. FSH increases testosterone production by the Leydig cells.

Question 15

Which of the following statements is FALSE regarding gametal DNA repair?
a. DNA repair in spermatogenic cells is dependent on the dose of chemical.
b. Spermiogenic cells are less able to repair damage from alkylating agents.
c. Female gametes have base excision repair capacity.
d. Meiotic maturation of the oocyte decreases its ability to repair DNA damage.
e. Mature oocytes and mature sperm no longer have the ability to repair DNA damage.

Answer 15

e. Mature oocytes and mature sperm no longer have the ability to repair DNA damage.

Question 16

Reduction division takes place during the transition between which two cell types during spermatogenesis?

Answer 16

Primary spermatocyte and secondary spermatocyte

Question 17

Which of the following cell types is properly paired with the substance it secretes?
a. ovarian granulosa cells - progesterone
b. Leydig cells – ABP.
c. ovarian thecal cells – estrogens.
d. Sertoli cells – testosterone.
e. gonadotroph – LH

Answer 17

e. Gonadotroph – LH

Question 18

Which of the following statements regarding male reproductive capacity is FALSE?
a. Klinefelter’s syndrome male are sterile.
b. FSH levels are often measured in order to determine male reproductive toxicity of a particular toxin.
c. Divalent metal ions, such as AN, Hg, and Cu, act as androgen receptor antagonists and affect male reproduction.
d. The number of sperms produced per day is approximately the same in all males.
e. ABP is an important biochemical marker for testicular injury.

Answer 18

d. The number of sperms produced per day is approximately the same in all males

Question 19

Reduction of sperm production can be caused by all of the following diseases EXCEPT:
a. hypothyroidism.
b. measles.
c. Crohn’s disease.
d. renal failure.
e. mumps.

Answer 19

b. Measles

Question 20

Of the following, which is LEAST likely to be affected by estrogen?
a. nervous system.
b. musculoskeletal system.
c. digestive system.
d. cardiovascular system.
e. urinary system.

Answer 20

c. Digestive system

Question 21

There is evidence that certain dietary components are carcinogenic. Which of the following is NOT tabbed as a dietary carcinogen?
a. excessive caloric intake
b. excessive alcohol consumption
c. aflatoxin B1 (food consumption)
d. insufficient caloric intake
e. nitrites (found in some lunchmeats)

Answer 21

Insufficient caloric intake

Question 22

Which of the following statements regarding mechanisms of chemical carcinogenesis is FALSE?
a. Procarcinogens require metabolism in order to exert their carcinogenic effect.
b. Free radicals are highly reactive molecules that have a single, unpaired electron.
c. DNA adducts interfere with the DNA replication machinery.
d. Mutations in the DNA and failure to repair those mutations can be highly carcinogenic.
e. Biological reduction of molecular oxygen is the only way free radicals can be formed.

Answer 22

e. Biological reduction of molecular oxygen is the only way free radicals can be formed

Question 23

In addition to being necessary for transcription to occur, which of the following transcription factors also plays a crucial role in nucleotide excision repair?

Answer 23

TFIIH

Question 24

Which of the following statements regarding DNA repair is TRUE?
a. Base excision repair requires the removal of a longer piece of DNA in comparison with nucleotide excision repair.
b. The repair of double-stranded DNA breaks is more prone to error than is base excision repair.
c. Dimerization of pyrimidines is required via base excision repair.
d. Mismatch repair can only recognize normal nucleotides that are paired with a noncomplementary nucleotide.
e. Nucleotide excision and base excision are tolerance mechanisms used to respond to DNA damage.

Answer 24

b. The repair of double-stranded DNA breaks is more prone to error than is base excision repair

Question 25

Which of the following statements is a characteristic of the initiation stage of carcinogenesis? a. Initiation is reversible in viable cells. b. The dose-response exhibits an easily measureable threshold. c. Cell division is required for the fixation of the process. d. All initiated cells survive over the lifespan of the organism. e. Spontaneous initiation of cell is a rare occurrence.

Answer 25

c. Cell division is required for the fixation of the process

Question 26

Tumor suppressor genes are mutated in a majority of cancers. Which of the following is NOT a characteristic of a tumor suppressor gene? a. A mutation in a tumor suppressor gene is dominant. b. Germ line inheritance of a mutated tumor suppressor gene is often involved with cancer development. c. There is considerable tissue specificity for cancer development. d. The p53 gene is a tumor suppressor gene that also acts as a transcription factor. e. Mutations in tumor suppressor genes can result in loss of cell cycle control.

Answer 26

a. A mutation in a tumor suppressor gene is dominant

Question 27

Which of the following molecules does NOT play an important role in cell cycle regulation? a. p53 b. cyclin-D c. MAPK d. MHC e. E2F

Answer 27

d. MHC

Question 28

Which of the following environmental factors is proportionally responsible for the LEAST amount of cancer deaths? a. tobacco b. infection c. diet d. sexual behavior e. alcohol

Answer 28

d. Sexual behavior

Question 29

The evidence of the carcinogenicity of dietary intake is sufficient to include one’s diet as associated with neoplasms of all of the following EXCEPT: a. colon b. breast c. pancreas d. endometrium e. gallbladder

Answer 29

c. Pancreas

Question 30

Which of the following is the correct definition of a complete carcinogen?

Answer 30

A chemical possessing the ability of inducing cancer from normal cells, usually possessing properties of initiating, promoting, and progression agents

Question 31

Five identical experimental animals are treated with 1 mg of one of the following toxins. The animal treated with which toxin is most likely to die? a. ethyl alcohol (LD50 = 10,000 mg/kg) b. botulinum toxin (LD50 = 0.00001 mg/kg) c. nicotine (LD50 = 1 mg/kg) d. ferrous sulfate (LD50 = 1500 mg/kg) e. picrotoxin (LD50 = 5 mg/kg)

Answer 31

b. Botulinum toxin (LD50 = 0.00001 mg/kg)

Question 32

Place the following mechanisms of toxin delivery in order from most effective to least effective: 1: intravenous 2: subcutaneous 3: oral 4: inhalation 5: dermal a. 1, 5, 2, 4, 3 b. 4, 1, 2, 3, 5 c. 1, 4, 2, 3, 5 d. 4, 2, 1, 5, 3 e. 1, 4, 3, 2, 5

Answer 32

c. 1, 4, 2, 3, 5 -Intravenous -Inhalation -Subcutaneous -Oral -Dermal

Question 33

A toxin with a half-life of 12 h is administered every 12 h. Which of the following is true? a. The chemical is eliminated from the body before the next dose is administered. b. The concentration of the chemical in the body will slowly increase until the toxic concentration is attained. c. A toxic level will not be reached, regardless of how many doses are administered. d. Acute exposure to the chemical will produce immediate toxic effects. e. The elimination rate of the toxin is much shorter than the dosing interval.

Answer 33

b. The concentration of the chemical in the body will slowly increase until the toxic concentration is attained

Question 34

Urushiol is the toxin found in poison ivy. It must first react and combine with proteins in the skin in order for the immune system to recognize and mount a response against it. Urushiol is an example of which of the following?

Answer 34

Hapten

Question 35

Toxic chemicals are most likely to be transformed in which of the following organs?

Answer 35

Liver

Question 36

When chemicals A and B are administered simultaneously, their combined effects are far greater than the sum of their effects when given alone. The chemical interaction between chemicals A and B can be described as which of the following?

Answer 36

Synergistic

Question 37

With respect to dose-response relationships, which of the following is true? a. Graded dose-response relationships are often referred to as "all or nothing" responses. b. Quantal dose-response relationships allow for the analysis of a population's response to varying dosage. c. Quantal relationships characterize the response of an individual to varying dosages. d. A quantal dose-response describes the response of an individual organism to varying doses of a chemical. e. The dose-response always increases as the dosage is increased.

Answer 37

b. Quantal dose-response relationships allow for the analysis of a population's response to varying dosage

Question 38

When considering the dose-response relationship for an essential substance:

Answer 38

Adverse responses increase in severity with increasing or decreasing dosages outside of homeostatic range

Question 39

The therapeutic index of a drug:

Answer 39

Describes the ratio of the toxic dose to the therapeutic dose of a drug

Question 40

Penicillin interferes with the formation of peptidoglycan cross-links in bacterial cell walls, thus weakening the cell wall and eventually causing osmotic death of the bacterium. Which of the following is true? a. Treatment with penicillin is a good example of selective toxicity. b. Penicillin interferes with human plasma membrane structure. c. Penicillin is a good example of a drug with low therapeutic index. d. Penicillin is also effective in treating viral infections. e. Penicillin is completely harmless to humans.

Answer 40

a. Treatment with penicillin is a good example of selective toxicity

Question 41

Which of the following is NOT important in hazard identification? a. structure-activity analysis b. in vitro tests c. animal bioassays d. susceptibility e. epidemiology

Answer 41

d. Susceptibility

Question 42

The probability of an adverse outcome is defined as:

Answer 42

Risk

Question 43

The systematic scientific characterization of adverse health effects resulting from human exposure to hazardous agents is the definition of:

Answer 43

Risk assessment

Question 44

Which of the following is NOT an objective of risk management? a. setting target levels for risk b. balancing risks and benefits c. calculating lethal dosages d. setting priorities for manufacturers e. estimating residual risks

Answer 44

c. Calculating lethal dosages

Question 45

Which of the following is NOT a feature in the design of standard cancer bioassays? a. more than one species b. both sexes c. near lifetime exposure d. approximately 50 animals per dose group e. same dose level for all groups

Answer 45

e. Same dose level for all groups

Question 46

Which of the following types of epidemiologic study is always retrospective?

Answer 46

Case-control

Question 47

Which of the following is defined as the highest nonstatistically significant dose tested?

Answer 47

NOAEL

Question 48

Which of the following represents the dose below which no additional increase in response is observed?

Answer 48

Threshold

Question 49

Which of the following is NOT needed to calculate the reference dose using the BMD method? a. MF b. percent benchmark response c. NOAEL d. UF e. benchmark dose

Answer 49

c. NOAEL

Question 50

Virtually safe doses are described at which confidence level?

Answer 50

95%

Question 51

Biotransformation is vital in removing toxins from the circulation. All of the following statements regarding biotransformation are true EXCEPT: a. Many toxins must be biotransformed into a more lipid-soluble form before they can be extracted from the body. b. The liver is the most active organ in the biotransformation of toxins. c. Water solubility is required in order for many toxins to be excreted by the kidney. d. The kidney plays a major role in eliminating toxicants from the body. e. The lungs play a minor role in ridding the body of certain types of toxins.

Answer 51

a. Many toxins must be biotransformed into a more lipid-soluble form before they can be extracted from the body.

Question 52

Which of the following statements about active transport across cell membranes is FALSE? a. Unlike simple of facilitated diffusion, active transport pumps chemicals against an electrochemical or concentration gradient. b. Unlike simple diffusion, there is a rate at which active transport becomes saturated and cannot move chemicals any faster. c. Active transport requires the expenditure of ATP in order to move chemicals against electrochemical or concentration gradients. d. Active transport exhibits a high level of specificity for the compounds that are being moved. e. Metabolic inhibitors do not affect the ability to perform active transport.

Answer 52

e. Metabolic inhibitors do not affect the ability to perform active transport.

Question 53

Which of the following might increase the toxicity of a toxin administered orally?

Answer 53

Increased dilution of the toxin dose

Question 54

Which of the following most correctly describes the first-pass effect?

Answer 54

Orally administered toxins are partially removed by the GI tract before they reach the systemic circulation

Question 55

Which of the following is an important mechanism of removing particulate matter from the alveoli?

Answer 55

Absorption into the bloodstream, followed by excretion via the kidneys.

Question 56

For a toxin to be absorbed through the skin, it must pass through multiple layers in order to reach the systemic circulation. Which of the following layers is the most important in slowing the rate of toxin absorption through the skin?

Answer 56

Stratum corneum

Question 57

A toxin is selectively toxic to the lungs. Which of the following modes of toxin delivery would most likely cause the LEAST damage to the lungs? a. intravenous. b. intramuscular. c. intraperitoneal. d. subcutaneous. e. inhalation.

Answer 57

c. Intraperitoneal

Question 58

Which of the following is NOT an important site of toxicant storage in the body? a. adipose tissue. b. bone. c. plasma proteins. d. muscle. e. liver.

Answer 58

d. Muscle

Question 59

Which of the following regarding the blood-brain barrier is TRUE: a. The brains of adults and newborn are equally susceptible to harmful blood-borne chemicals. b. The degree of lipid solubility is a primary determinant in whether or not a substance can cross the blood-brain barrier. c. Astrocytes play a role in increasing the permeability of the blood-brain barrier. d. Active transport processes increase the concentration of xenobiotics in the brain. e. The capillary endothelial cells of the CNS possess large fenestrations in their basement membranes.

Answer 59

b. The degree of lipid solubility is a primary determinant in whether or not a substance can cross the blood-brain barrier

Question 60

Which of the following will result in DECREASED excretion of toxic compounds by the kidneys? a. a toxic compound with a molecular weight of 25,000 Da. b. increased activity of the multidrug-resistance (mdr) protein. c. increased activity of the multiresistant drug protein. d. increased activity of the organic cation transporter. e. increased hydrophilicity of the toxic compound.

Answer 60

d. Increased activity of the organic cation transporter

Question 61

Xenophobic biotransformation is performed by multiple enzymes in multiple subcellular locations. Where would one of these enzymes most likely NOT by located? a. cytosol. b. Golgi apparatus. c. lysosome. d. mitochondria. e. microsome.

Answer 61

b. Golgi apparatus

Question 62

All of the following statements regarding hydrolysis, reduction, and oxidation biotransformations are true EXCEPT: a. The xenobiotic can be hydrolyzed. b. The xenobiotic can be reduced. c. There is a large increase in hydrophilicity. d. The reactions introduce a functional group to the molecule. e. The xenobiotic can be oxidized.

Answer 62

c. There is a large increase in hydrophilicity.

Question 63

Which of the following is often conjugated to xenobiotics during phase II biotransformations?

Answer 63

Sulfate group

Question 64

Which of the following is a true statement about the biotransformation of ethanol? a. Alcohol dehydrogenase is only present in the liver. b. Ethanol is reduced to acetaldehyde by alcohol dehydrogenase. c. Ethanol and hydrogen peroxide combine to form acetaldehyde with the aid of catalase. d. In spite of its catalytic versatility, cytochrome P450 does not aid in ethanol oxidation. e. Acetaldehyde is oxidized to acetic acid in the mitochondria by aldehyde dehydrogenase.

Answer 64

e. Acetaldehyde is oxidized to acetic acid in the mitochondria by aldehyde dehydrogenase

Question 65

Which of the following enzymes is responsible for the biotransformation and elimination of serotonin?

Answer 65

Monoamine oxidase

Question 66

Which of the following reactions would likely NOT be catalyzed by cytochrome P450? a. dehydrogenation. b. oxidative group transfer. c. epoxidation. d. reductive dehalogenation. e. ester cleavage.

Answer 66

e. Ester cleavage

Question 67

All of the following statements regarding cytochrome P450 are true EXCEPT: a. Poor metabolism or biotransformation of xenobiotics is often due to a genetic deficiency in cytochrome P450. b. Cytochrome P450 can be inhibited by both competitive and noncompetitive inhibitors. c. Certain cytochrome P450 enzymes can be induced by one’s diet. d. Increased activity of cytochrome P450 always slows the rate of xenobiotic activation e. Induction of cytochrome P450 can lead to drug tolerance

Answer 67

d. Increased activity of cytochrome P450 always slows the rate of xenobiotic activation

Question 68

Which of the following statements regarding phase II biotransformation (conjugation) reactions is true? a. Phase II reactions greatly increase the hydrophilicity of the xenobiotic. b. Phase II reactions are usually the rate-determining step in the biotransformation and excretion of xenobiotics. c. Carboxyl groups are very common addition of phase II reactions. d. Most phase II reactions occur spontaneously. e. Increased phase II reactions result in increased xenobiotic storage in adiopocytes.

Answer 68

a. Phase II reactions greatly increase the hydrophilicity of the xenobiotic

Question 69

Where do most phase II biotransformations take place?

Answer 69

Cytoplasm

Question 70

Which of the following is NOT an important co-substrate for phase II biotransformation? a. UDP-glucoronic acid. b. 3’-phosphoadenosine-5’-phosphosulfate (PAPS). c. S-adenosylmethionine (SAM). d. N-nitrosodiethylamine. e. acetyl CoA

Answer 70

d. N-nitrosodiethylamine

Question 71

The Phase II reaction occurring in the brain believed to be responsible for producing a metabolite 600x more potent than morphine is:

Answer 71

Glucuronidation

Question 72

The severity of a toxin/toxicant depends, in large part, on the concentration of the toxin/toxicant at its site of action. Which of the following will decrease the amount of toxin/toxicant reaching its site of action? a. Absorption across the skin b. Excretion via the kidneys c. Metabolic activation d. Reabsorption across the intestinal mucosa e. Discontinuous endothelial cells of hepatic sinusoids

Answer 72

b. Excretion via the kidneys

Question 73

Metabolic activation (toxication) is the biotransformation of a toxin/toxicant to a more toxic or reactive species. Which of the following is NOT a reactive chemical species commonly formed by metabolic activation (toxication)? a. Electrophiles b. Nucleophiles c. Superoxide anions d. Hydroxy radicals e. Hydrophilic organic acids

Answer 73

e. Hydrophilic organic acids

Question 74

Which of the following is NOT an important step in the detoxification of chemicals? a. Formation of redox-active reactants b. Reduction of hydrogen peroxide by glutathione peroxidase c. Formation of hydrogen peroxide by superoxide dismutase d. Reduction of glutathione disulfide (GSSG) by glutathione reductase (GR) e. Conversion of hydrogen peroxide to water and molecular oxygen by catalase

Answer 74

a. Formation of redox-active reactants

Question 75

Regarding the interaction of the ultimate toxicant with its target molecule, which of the following is FALSE? a. Toxins often oxidize or reduce their target molecules, resulting in the formation of a harmful by-product b. The covalent binding of a toxin with its target molecule permanently alters the target’s function c. The noncovalent binding of a toxin to an ion channel irreversibly inhibits ion flux through the channel d. Abstraction of hydrogen atoms from endogenous compounds by free radicals can result in the formation of DNA adducts e. Several toxins can act enzymatically on their specific target proteins

Answer 75

c. The noncovalent binding of a toxin to an ion channel irreversibly inhibits ion flux through the channel

Question 76

All of the following are common effects of toxicants on target molecules EXCEPT: a. Blockage of neurotransmitter receptors b. Interference with DNA replication due to adduct formation c. Cross-linking of endogenous molecules d. Opening of ion channels e. Mounting of an immune response

Answer 76

d. Opening of ion channels

Question 77

Which of the following proteins functions to prevent the progression of the cell cycle?

Answer 77

IκB

Question 78

Which of the following would have the largest negative impact on intracellular ATP levels? a. Moderately decreased caloric intake b. Interference with electron delivery to the electron transport chain c. Inability to harvest ATP from glycolysis d. Increased biomolecule synthesis e. Active cell division

Answer 78

b. Interference with electron delivery to the electron transport chain

Question 79

What happens when a toxin/toxicant induces elevation of cytosolic calcium?

Answer 79

Mitochondrial uptake of calcium dissipates the electrochemical gradient needed to synthesize ATP

Question 80

Cytochrome c is an important molecule in initiating apoptosis in cells. All of the following regarding cytochrome c are true EXCEPT: a. The release of cytochrome c into the cytosol is an important step in apoptosis initiation. b. The loss of cytochrome c from the electron transport chain blocks ATP synthesis by oxidative phosphorylation c. Loss of cytochrome c from the inner mitochondrial membrane results in increased formation of reactive oxygen species d. Bax proteins mediate cytochrome c release e. Caspases are proteases that increase cytosolic levels of cytochrome c

Answer 80

e. Caspases are proteases that increase cytosolic levels of cytochrome c

Question 81

Which of the following is NOT associated with carcinogenesis? a. Mutation b. Normal p53 function c. Ras activation d. Apoptosis inhibition e. DNA repair failure

Answer 81

b. Normal p53 function

Question 82

Which molecule determines whether a toxicant damaged cell undergoes necrosis or apoptosis?

Answer 82

ATP

Question 83

During the process of lipid peroxidation, lipid hydroperoxide (LOOH) is converted to the highly reactive lipid alkoxyl radical (LO-) via

Answer 83

The Fenton reaction

Question 84

DNA insult, such as a double stranded DNA break, directly activates __, an important nucleic, pro-apoptotic signaling molecule.

Answer 84

p53

Question 85

The mitochondrial protein that is released into the cytosol upon mitochondrial membrane potential dissipation triggering the intrinsic apoptotic pathway via binding to Apaf-1 and ATP is:

Answer 85

Cytochrome c

Question 86

Cytochrome c specifically cleaves which procaspase into its active form: (M4)

Answer 86

Procaspase 9

Question 87

The amino acids used as substrates in the conjugation of aromatic hydroxylamine-containing xenobiotics are:

Answer 87

1. Serine 2. Proline

Question 88

The Phase II reaction(s) that exhibits [a] very significant genetic polymorphism(s), specifically in isoniazid metabolism, is/are

Answer 88

Acetylation

Question 89

The amino acids used as substrates in the conjugation of carboxylate-containing xenobiotics are:

Answer 89

1. Glycine 2. Glutamine 3. Taurine

Question 90

The Phase II reaction(s) that tend(s) to favor conjugation to all the heteroatoms: O, N, S is/are:

Answer 90

1. Methylation 2. Glucuronidation 3. Glutathione conjugation

Question 91

The Phase II reaction(s) that generally decrease(s) resultant metabolite water solubility is/are:

Answer 91

Methylation

Question 92

The Phase II reaction that generally possesses the highest concentration of cofactor is:

Answer 92

Glutathione conjugation

Question 93

The insertion of the mitochondrial permeability transition pore (MPTP) complex is mediated by:

Answer 93

1. A significant increase in the amount of free Ca2+ within the mitochondrial matrix 2. A significant change in the voltage across the inner mitochondrial membrane

Question 94

The Phase II reaction(s) whose rates are limited by cofactor availability is/are:

Answer 94

1. Glucuronidation 2. Sulfonation 3. Glutathione conjugation