key topics for midterm

phase I metabolism often uses ________ enzymes to add or expose functional groups, such as _______ or an ___________. this makes a chemical more _________ or sometimes more toxic

CYP450, -OH, epoxide, reactive

phase I reactions include oxidation, reduction, and ____________

hydrolysis

phase II metabolism attaches a substance such as glucuronic acid, sulfate, or __________(GSH) to a toxicant. this usually makes it more ________ and easier to excrete

glutathione, hydrophilic

a lipophilic chemical can more readily cross a cell’s ______ membrane, while a hydrophilic chemical generally crosses it ______ easily

plasma, less

the rate of simple diffusion increases with membrane surface area and the concentration difference, but decreases as membrane _________ increases

thickness

the usual absorption speed from fastest to slowest is

IV, inhalation, oral, dermal

risk depends on the chemical’s hazard and the peron’s ________, including the dose and duration

exposure

the lecture estimates RfD from NOAEL as NOAL / _________. when using LOAEL, it uses LOAEL / ____________

100, 1000

bioaccumulation is buildup of a toxicant within _________ organism over time while biomagnification is increasing concentration across __________ levels/species often up the food chain

one, trophic

pyrethroids and DDT disrupt action potentials by preventing __________ of voltage-gated __________ channels, keeping them open longer

inactivation, Na+

prolonged sodium-channel opening disrupts nerve signaling and can cause muscle __________, respiratory failure, or cardiac problems

paralysis

mammals are less susceptible to pyrethroids partly because they can _________ them quickly, their sodium (Na+) channels bind them less strongly and pyrethroids are more effective at _________ temps

metabolize, lower

natural pyrethrins break down relatively quickly; synthetic pyrethroids generally persist _________ in the environment

longer

organophosphates are converted into toxic __________ forms that inhibit ____________ (AChE), the enzyme that breaks down acetylcholine

oxon, acetylcholinesterase

when AChE is inhibited, ____________ (ACh) builds up in the synapse and overstimulates nicotinic and muscarinic receptors

acetylcholine

organophosphate poisoning can cause excessive salivation, constricted pupils, muscle contractions, and breathing difficulty, a major cause of death is _________ failure

respiratory

__________ treats organophosphate poisoning by blocking __________ effects, 2-PAM can restore AChE if given before the enzyme undergoes __________

atropine, muscarinic, aging

neonicotinoids such as imidaclopri act on __________ acetylcholine receptors

nicotinic

two environmental concerns about neonicotinoids are harm to __________ and the possible formation of a more toxic product through aquatic ___________

honeybees, photolysis

many herbicides are less toxic to mammals because they target processes specific to __________. glyphosate inhibits _________ synthase, disrupting production of three _________ acids

plants, EPSP, amino

the three amino acids whose production is affected by glyphosate are phenylalanine, tyrosine, and __________-

tryptophan

DDT is a persistent, lipophilic __________ pesticide that can bioaccumulate and biomagnify through food chains

organochlorine

DDT can be broken down into DDE, which causes bird _________ thinning by disrupting _________ and prostaglandin metabolism

eggshell, calcium

dioxin is not considered _____________; its tumor-__________ effects relate to endocrine disruption and weakened immune surveillance, allowing damaged cells to _________ and grow

mutagenic, promoting, survive

shrinkage of the thymus can impair _____ cell maturation and reduce ________ surveillance against abnormal cells

T, immune

vinyl chloride is mainly absorbed by _________ and is metabolized in the liver by ________ enzymes

inhalation, CYP

a reactive vinyl chloride metabolite can form DNA -_________ and mutations, contributing to _______ tumors, especially _________ angiosarcoma

adducts, liver, hepatic

phase I metabolism of B[a]P can create a reactive _______ that binds with DNA, especially the base __________

epoxide, guanine

a B[a]P DNA adduct can cause a _______ mutation during DNA _________. this is called tumor ____________ and is irrversible

point, replication, initiation

dioxin can act as a tumor __________- by promoting survival and growth of damaged cells; B[a]P can act as both an ________ and a promoter

promoter, initiator

hypoglycin A metabolism consumes _______, impairing fatty-acid oxidation and aerobic energy production

CoA

with enzyme production impaired, the body relies more on _________ or _________ for ATP, sotred glucose may become depleted

glucose, glycolysis

Skipping an evening meal may worsen hypoglycin A toxicity because it reduces available glucose stores; the brain is especially vulnerable because neurons rely on __________ for energy.

glucose

Polyvinyl chloride (PVC) is made from the monomer __________.

vinyl chloride

Plasticizers such as BPA and __________ may be added to plastics to increase flexibility or durability.

phthalates

Microplastics are plastic particles smaller than __________ mm.

5

A source of microplastic fibers is synthetic clothing, especially __________; fibers are released during washing and everyday use.

fleece

Tiny fibers can travel away from their source through the __________ and later settle in snow and ice, including in the Arctic and European Alps.

air

Microplastics can harm wildlife through ingestion and __________; the lecture notes that their health effects in humans remain __________.

entanglement, uncertain

Finding microplastics in blood or brain tissue—and finding an association with disease—does not by itself prove __________.

causation

The lecture reports that only about __________% of plastics are recycled and used multiple times, while plastic waste is difficult to remove because it is largely __________.

5, non-biodegradable