Quiz 6

Question 1

What caused PFAS to be added into couches?

Answer 1

1975 California furniture flammability required polyurethane foam in couches to be able to withstand small open flame for 12 seconds (followed across nation)

Question 2

what are some problems with phasing out hazardous chemicals?

Answer 2

good in theory but need to find alternatives and there are possible unknown hazards with the alternatives.

Question 3

couch flame retardants

Answer 3

flame retardants are used to meet the flammability standard for polyurethane foam, unfortunately contain lots of halogens (bromine and chlorines) and are persistent chemicals and endocrine disruptors

Question 4

How did they fix the flame retardant rule

Answer 4

California law requires upholstered furniture to have a label stating if it has fire retardants, pre 2015 has flame retardants, after is replaced with healthier retardant free material

Question 5

Toxicokinetics

Answer 5

how a substance gets into the body and what happens to it in the body, Toxicokinetics deals with what the body does with a drug when given a relatively high dose relative to the therapeutic dose

Question 6

what does ADME stand for

Answer 6

absorption, distribution, metabolism, excretion

Question 7

factors determining the severity of toxicity

Answer 7

duration and concentration
rate and amount
distribution
efficiency
ability
amount of duration of storage
rate and sites of excretion
age and health status

Question 8

Absorption

Answer 8

toxiokinetics, a highly toxic substance that is poorly absorbed may be no more hazardous than a substance of low toxicity that is highly absorbed

Question 9

biotransformation

Answer 9

two substances with equal toxicity and absorption may differ in how hazardous they are depending on the nature of their biotransformation

Question 10

what is the more toxic biotransformation

Answer 10

A substance that is biotransformed into a more toxic metabolite (bioactivated) is a greater hazard than a substance that is biotransformed into a less toxic metabolite (detoxified).

Question 11

Toxic substances control act

Answer 11

authorizes the EPA to regulate and screen all chemicals produced or imported into the United States to prevent unreasonable risks to health and the environment

Question 12

How did Quats avoid the toxic substances control act

Answer 12

Quats entered the market in the early 20th century before the toxic substances control act so they counted as existing chemicals on the market that didn’t need to be evaluated for consumer safety

Question 13

Quats

Answer 13

Quaternary Ammonium Compounds, QAC
used ad disinfectants and common cleaner during covid

Question 14

who found Quats

Answer 14

Gerhard Domagk, originally used as a biocidal activity

Question 15

Structure of Quats

Answer 15

Discovered if at least one of the groups borne by the cationic nitrogen was a long-chained alkyl group, the compound could kill microbes.

Question 16

How do quats work?

Answer 16

The positive charge allows it to adhere to negatively-charged surfaces of bacteria and viruses.
Once attached to bacteria, long alkyl chain inserts into the microbes’ lipid membranes, bursting this outer layer and causing cellular contents to leak out.
Against viruses, quats disrupt their protein and lipid structures.

Question 17

Quats use other than disinfection

Answer 17

preservative for wood treatments and eye drops
antiseptic ingredient in mouthwashes, nasal sprays, and throat lozenges
pesticides
surfactants in detergents and shampoos, dryer sheets, fabric softeners
removing oil/gas from the earth

Question 18

Mouse story with Quats

Answer 18

Quats cause a gab in the neural tube that did not close between brain and spinal chord
Her control mice suddenly also showed the neural tube gap
Changed disinfectant to Quats which was causing the neural tube gaps

Question 19

What happens to a substance after it is absorbed?

Answer 19

after a substance is absorbed it is distributed through the blood, lymph circulation, and extracellular fluids
then the substance or its metabolites are eliminated through the body’s waste products

Question 20

Xenobiotics

Answer 20

substances that are foreign to the body or to an ecological system.

Question 21

transporters

Answer 21

aka transport proteins, play an important role in the process of ADME, active transport

Question 22

Diffusion

Answer 22

net movement of a substance traveling down its concentration gradient (high to low)

Question 23

Facilitated diffusion

Answer 23

molecules moving from high to low concentration but using a protein channel to cross membrane

Question 24

factors affecting rate of diffusion

Answer 24

distance, temperature, characteristics of the solvent, characteristics of the molecules, characteristics of the barrier (selectively permeable phospholipid bilayer), changing of concentrations

Question 25

Absorption

Answer 25

toxicants gain entrance, must cross the cellular barriers of GI or respiratory after ingestion/inhalation
a substance must be absorbed to exert an effect on internal organs

Question 26

What factors influence is a xenobiotic will be absorbed

Answer 26

route of exposure, concentration, chemical and physical properties

Question 27

How can route of exposure cause variation in absorption

Answer 27

skin, oral, and respiratory the absorbed dose is only a fraction of external dose
for injections/implantations exposure dose is same as internal dose (ex) DDT mostly not absorbed on skin but highly absorbed orally)

Question 28

How are substances ranked by hazard?

Answer 28

xenobiotics are often ranked for hazard in accordance with the route of exposure, a substance may be non-toxic by one route and highly toxic by another

Question 29

Routes of exposure examples

Answer 29

inhalation, ingestion, dermal, injections, implants, conjunctival instillations (eye drops), suppositories

Question 30

role of cell membranes in absorption

Answer 30

xenobiotic must pass across cell membranes to enter body
cells in solid tissues are so tightly compacted that substances cannot pass through them, a xenobiotic must cross several membranes to go from one area of the body to another

Question 31

Passive transfer

Answer 31

simple diffusion/ osmotic filtration, is “passive” because no cellular energy or assistance is required

Question 32

Primary forms of specialized transport

Answer 32

facilitated diffusion, active transport, endocytosis (phagocytosis and pinocytosis)

Question 33

2 forms of passive transfer

Answer 33

1) differences in concentrations causes a substance to move from higher to lower, diffusion
2) facilitated diffusion by a substance moving through pores in the membrane or the lipophilic interior of the membrane

Question 34

Facilitated diffusion

Answer 34

Mediated by enzymes/proteins—high specificity
Always faster than passive diffusion
Inhibition is a possible toxic response
ex) transport of sugar and amino acids into RBCs and the CNS

Question 35

competitive diffusion

Answer 35

the toxic compound ’looks’ like the natural substrate of the enzyme/protein

Question 36

noncompetitive diffusion

Answer 36

toxic compound does not resemble to the natural substrate of the enzyme

Question 37

Active transport

Answer 37

movement through the membrane is against the concentration gradient (low to high), requires ATP
Active transport is important in the transport of xenobiotics into the liver, kidney, and central nervous system and for maintenance of electrolyte and nutrient balance.

Question 38

Rate of absorption

Answer 38

determinant of acute toxic effects, gut and lungs provide rapid absorption (more passive), affected by ionization of chemical and the vehicle used, lipid high xenobiotics have lower absorption