Lecture 1-3 Flashcards
what is a pollutant?
chemical which causes environmental harm
what is a contaminant?
chemical present at harmful levels
what is a biomarker?
biological response to a toxic compound -Molecular, cellular, organismal
describe xenobiotic and what it means
- Anthropogenic products, do not play a functional biochemical role
- “xeno”= new/outside/novel
- “genic” to produce/make
what are toxins effects on evolution? (2)
- Arms race
- Resistance
page 14 on first lecture
yay last thing:)
describe inorganic metals (4)
- Good conductor of electricity (enters reaction as a cation)
- Present on Earth since its formation (natural, essential, hazardous)
- Often enter the ecotox world through mining activities
- Form covalent bonds and can transfer electrons
- ->∙O2- ∙OH
for inorganic metals, bonding to organic groups makes ________. ______ properties can …….
- lipophilic compounds
- Lipo
- alter chemical activity of the ionic form of the same element e.g. methylated arsenic
describe how the term “heavy metals” has changed from its previous meaning to its present meaning
Previously: density (relative to water) > 5
Now: chemical activity
e.g. Aluminum
• Fish gills in acidified lakes: causes lesions, disrupts oxygen uptake
• Deposits in human brains implicated in Alzheimer’s
- ) Metals can ……
2. ) Metals differ in their _______
- ) move freely from association to association
2. ) toxicity
why can metals not biodegradable
because they are elements; they cannot be broken down into simpler substances because they are already in the simplest form. They cannot even be broken down by chemical means
what are trace elements?
a chemical element required only in minute amounts by living organisms for normal growth.
give some example of trace elements
Fe, I, Cu, Mn, Zn, Co, Mo, Se, Cr, Ni, V, Si, As
Only plants need….
Boron (B)
Some metals can induce a ______ of others. Example?
–e.g. low [Mo] can cause Cu deficiency in cattle
- ) By themselves, 3 three compounds are not toxic
2. ) However, excessive amounts lead to _______________
- ) PO4-, NO3-, NH4+
2. ) Eutrophication
what is eutrophication?
excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen
what is Methemoglobinemia
“Blue Baby Syndrome”
a blood disorder in which an abnormal amount of methemoglobin – a form of hemoglobin – is produced. With methemoglobinemia, the hemoglobin can carry oxygen but is unable to release it effectively to body tissues.
what are oxyradicals?
- Free Radicals and Reactive Oxygen. A radical is an atom or group of atoms that have one or more unpaired electrons. -Radicals can have positive, negative or neutral charge.
ie: O2- and OH-
what is an organic molecule?
a molecule that has a carbon
what is a hydrocarbon ?
a compound of hydrogen and carbon, such as any of those that are the chief components of petroleum and natural gas
what are alkanes?
hydrocarbons with only single bonds between the atoms.
what are alkenes?
hydrocarbons with at least one double bond.
what are alkynes?
hydrocarbons with at least one triple bond
what are aromatics? describe them (4)
A substance or plant emitting a pleasant and distinctive smell.
- Base is Benzene ring
- Can be saturated or unsaturated
- Not always Hydrogens
- Polycyclic aromatic hydrocarbons (PAHs)
Hydrocarbons are typically found in…..(2)
Fossil Fuels
Byproducts
describe PCBs (6)
- Polychlorinated Biphenyls
- Anthropogenic: many industrial uses
- Stable, viscous
- 120 present in commercial products
- High lipid solubility
- One of the main players in SS
- What are the components of a PCB? Eg: dichloro-diphenyl-trichloroethane
what are 3 other Polychlorinated Compounds?
- ) Benzodioxins (PCDDs)
- ) Dibenzofurans (PCDFs)
- ) Polybrominated Biphenyls (PBBs)
describe Benzodioxins (PCDDs) (2)
- Leftover reaction of PCBs
* Dioxin: “rat poison”
describe Dibenzofurans (PCDFs)
- Similar leftover PCB reaction
- Few commercial applications/environmental attention
describe Polybrominated Biphenyls (2)
- Fire-retardants
- Highly lipophilic
what compounds are the primary focus of Silent Spring?
Organoclorine Insecticides
describe 3 different organoclorine insecticides and say something about each
- ) DDT
- Developed in 1939
- Banned in 1972
- Exported until 1985 - ) Aldrin/Dieldrin
- Cyclodienes
- introduced in the 1950s
- Lower vertebrate toxicity (40 mg / kg body wt)
- Crop pests, disease vectors - ) Hexachlorocyclohexane
- Somewhat polar
Organophosphorous Insectcicides function by inhibiting _____________
acetylcholinesterase
state how inhibiting acetylcholinesterase works as an insecticide and states some things about organophosphorous insecticides (5) (page 14)
- “Nerve gas”: weaponized
- Volatile and lipophilic
- Short-lived in the environment
- Can accumulate in phloem to target crop pests
- Also targets vertebrate pests
slide 17 and 18
Make sure to look at!:)
describe Carbamate Insecticides (6)
- Derived from Carbamic acid
- Inhibit acetylcholinesterase
- Usually solids
- More water soluble than organochlorines
- Break down readily in the environment -Typically target molluscs (but there are plant-specific carbamates)
describe Pyrethroid Insecticides
- Derived from chrysanthemum flowers
- Inhibit insect muscle action -Photodegraded
- Can persist in soil particles
- Generally not toxic to humans*
- Typical uses: vector insects (flies and mosquitos)
- Resistance
describe Neonicotinoids (6)
“Neonics”
- Similar to nicotine
- Less polar (probably some lipophilia)
- Insects more sensitive than verts
- Many chemical companies manufacture lots of neonics
- Proposed bans in Europe
- Associated with colony collapse disorder
Page 6 in lecture 3
:) Bees
Describe Phenoxy Herbicides (3)
-Same pathway as plant growth inhibitor (alkali salts = water soluble esters=lipophilic) -Control dicot weeds in monocot crops* (Dicots “grow to death”) -Agent Orange
*monocot crops= corn, wheat, rice, oats
describe Anticoagulant Rodenticide
Blood thinner & rat poison
- Antagonist to Vitamin K
- Many rats have resistance
- Lots of structurally similar compounds now used
- Accumulate in the liver
- Can also be biomagnified
describe detergents
-Typically act as surfactants
-Polar: anionic or cationic. Or totally non polar
-Endocrine disruptors
-have the same phospholipid bilayer (or similar to) as our cells
(slide 9)
describe chlorophenols (3)
- Chlorine + wood phenols = polychlorinated phenols
- Different from PCP the drug (Phencyclidine)
- Acidic properties, water soluble = chemically reactive
describe Ethinylestradiol (3)
- Common in oral contraceptives (the Pill)
- Enters through waste water
- Cause of intersex sturgeons in Missouri River
page 12
:)
what are 3 Organometallic Compounds?
- ) Mercury (methylmercury)
- ) Arsenic (methylarsenic)
- ) Tin (tributyl tin)
describe the organometallic compound methylmercury (2)
- Becomes lipophilic, interferes with internal chemical reactions
- Thimerosal contains ethylmercury and is cleared from the body metabolically, extremely low toxicity
describe the organometallic compound methylarsenic
herbicide and defoliant
describe the organometallic compound tributyl tin
- preventing boring invertebrates in wood
- devastating dog whelks
name and describe the four different radiation particles
- ) Alpha (a) – discharged He+, biologically damaging
- ) Beta (b) – e-, less biologically damaging
- ) Gamma (g) – electromagnetic radiation, pervasive, similar to b
- ) Neutron – no charge particles, liberated by a or b. Basis for nuclear fission
what is half life? (3)
- How long does it take for half of atoms to decay?
- After 10 half-lives, considered “not different” from background
- Safety and storage depends on the half-life
name some radioactive isotopes that are relevant to Biochemistry?
- 131I – Concentrated in the thyroid
- 90Sr – Follows Ca pathways and accumulates in bones
- 137Cs – Follows Fe pathways, blood
what are the 2 Gaseous Pollutants?
Greenhouse Gases and Air Pollutants
describe Greenhouse Gases (2)
- CO2, CH4, O3, CFC
* Global warming, Ozone destruction, Smog, Ocean acidification
describe Air Pollutants (2)
- NOX, SOX
* Acid rain–>aquatic and soil degradation
