Final

Question 1

What is toxicology?

Answer 1

The study of the adverse effects of chemicals or physical agents on living organisms

Question 2

What is considered a toxic agent?

Answer 2

Anything that can produce an adverse biological effect

Question 3

What the routes of exposure?

Answer 3

Dermal, respiratory, and digestive

Question 4

What is acute toxicity?

Answer 4

Short or immediate term toxicity that is frequently lethal

Question 5

What is chronic toxicity?

Answer 5

Long term toxicity that often has no immediate effects but whose effects accumulate over time. Often nonlethal

Question 6

What factors affect chemical toxicity?

Answer 6

MW, volatility, particle size, solubility, charge, shape, functional groups, quarternary alkyl moieties, cyanohydrin moiety, thiourea moiety, hydrazido moiety, log P, pKa, polar surface area, partition coefficients, acid/base properties, dipole moment, rotatable bonds, H-bonds

Question 7

How does detoxification work in the body and how does it happen?

Answer 7

Chemicals in the liver (in humans) are responsible for detoxification. In this process, a xenobiotic is converted to a less toxic form by (generally) converting lipid-soluble compounds to polar compounds

Question 8

What are the two types of metabolism of a chemical in the body?

Answer 8

Detoxification or toxification

Question 9

Which body organ is mostly involved in the excretion process for chemicals?

Answer 9

Kidneys

Question 10

What is antagonism and synergism in drug interactions?

Answer 10

Antagonism is when the two drugs have a lower effect than the sum of their effects and synergism is when two drugs have greater effect than the sum of their effects

Question 11

What is an example of antagonism in drug interactions?

Answer 11

barbituate overdose and vasospressor cure; mercury toxicity and dimercaprol cure; poison ingestion and swallowed charcoal cure

Question 12

What is an example of synergism in drug interactions?

Answer 12

Combination of asbestos and cigarette smoke; hepatoxicity of combined ethanol and carbon tetrachloride

Question 13

What is pKa?

Answer 13

pKa is a measure of how “willing” a molecule give up its H+. pKA < 1 is a strong acid and pKa > 1 is a weak acid

Question 14

How does pKa relate to skin irritation?

Answer 14

pKa < 4 or pKa > 8 causes skin irritation in humans

Question 15

What is the difference between hazard and risk?

Answer 15

Hazard is the intrinsic danger in a chemical, while risk is a chance of harm expressed as a function of hazard and exposure

Question 16

What are examples of physical and global hazards?

Answer 16

Global: climate change, acid rain, security threat, ozone depletion
Physical: explosivity, corrosivity, oxidizers/reducers, pH

Question 17

What is LEED certification?

Answer 17

Certification for design, construction, and operation of green buildings: site management, stormwater management, water use, energy use, building materials, and air quality. Comes in certified, silver, gold, and platinum

Question 18

How does Green Chemistry reduce risk?

Answer 18

Application of the 12 principles reduces intrinsic chemical hazards, reducing risk per the risk equation.

Question 19

What are the three important takeaways from a dose-response curve?

Answer 19

Causality
Establishes lowest dose with an effect (threshold dose)
Determines the rate of injury accumulation (slope)

Question 20

What is the difference between NOAEL and LOAEL?

Answer 20

NOAEL is the highest dose at which there was no observed response and LOAEL is the lowest dose at which there was an observed response

Question 21

What is LD50?

Answer 21

LD50 is the dose at which 50% of the population died.

Question 22

What is RfD and and what is it used for?

Answer 22

RfD is an estimate of the daily oral exposure to the human population that can be had without risk of effect

Question 23

What is the difference between effective dose and toxic dose and what do we look for in the curve overlap of these two curves? What is the margin of safety?

Answer 23

Ideally, we look for low overlap, where toxic doses are much higher than effective doses. The margin of safety is the shaded area on the graph of the toxic and effective dose-response curve above where there is an effective dose (>25%) and below TD50.

Question 24

In a dose-response curve comparison what are the two characteristic points you can use to compare them and make a choice on safety?

Answer 24

NOAEL and LOAEL

Question 25

What does the dose-response relationship help a toxicologist determine?

Answer 25

Causality Establishes lowest dose with an effect (threshold dose) Determines the rate of injury accumulation (slope)

Question 26

What parameters affect absorption in each the dermal, respiratory and digestive routes?

Answer 26

Dermal: liquid phase, logP between 0 and 5, MW < 400 Respiratory: vapor pressure > 0.001, size < 5 nm, MW < 400, logP between 0 and 5 Digestive: liquid phase, size < 5 nm, MW < 400, logP between 0 and 5

Question 27

What is the difference between absorption and distribution of a chemical and which one is easiest to control?

Answer 27

Absorption is chemicals entering the body and distribution is chemicals moving around inside the body. Absorption is much easier to control

Question 28

What are the five characteristics of an ‘ideal chemical’?

Answer 28

Good use potency (only need small amounts), easy clean and cheap manufacturing, minimal hazard, degrades into innocuous materials in the environment, and does not bioaccumulate or biomagnify

Question 29

Name some of the nucleophilic sites found in proteins and nucleic acids which are susceptible to damage through electrophilic attacks.

Answer 29

In general, like reacts with like (soft with soft and hard with hard). Some target nucleophilic site are the thiol site of cysteine, the S-atoms of methionine, primary amino groups, secondary amino group of histidine, primary amine groups of purine bases, in-ring N atoms of purine and pyrimidine bases, O-atoms of purine and pyrimidine bases, and phospate O atoms.

Question 30

What is the hardness of xenobiotic electrophiles?

Answer 30

Hardness is correlated with size and polarizability. Hard electrophiles are small, non-polarizable molecules and soft electrophiles are large, polarizable molecules

Question 31

What is oxidation and what is reduction, how are they defined and how do these apply to electrochemistry?

Answer 31

Oxidation is the loss of electrons and reduction is the gain of electrons. Flow of electrons resulting from this creates a current

Question 32

What are hydrogen fuel cells and what are the advantages and challenges of using them?

Answer 32

Fuel cells are types of batteries that use redox reactions between hydrogen and oxygen to produce water and electricity. They can provide emissions-free electricity and can store energy well, which is a key link in the path to a renewable future. However, they are expensive, current hydrogen production techniques also produce emissions, they are not yet a fully-fledged technology, and they can require extreme temperatures or pressures.

Question 33

What are some of the alternative sources of fuels currently considered to replace fossil fuels?

Answer 33

Corn, soy, sugarcane, municipal waste, waste oils, grasses, cellulosics, algae

Question 34

What are biofuels, what are the advantages in using them and what are some of the challenges in various generation biofuels?

Answer 34

Biofuels are liquid fuels made from biological sources rather than petroleum. They offer the advantages of being carbon-neutral to carbon-positive; safer to handle, store, and transport; have less toxic spills and a lower flash rate; independence from geopolitics; and do not require extractive mining. Challenges are, by generation: first, competition with agricultural land and products; seconds, complex structures and potentially expensive methods; third, energy, cost, and space intensive; and fourth, genetic engineering is hard, expensive, and can have unintended consequences