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Environmental Chemistry > Lecture 2 > Flashcards

Lecture 2 Flashcards

1
Q

What takes place in ER (endoplasmic reticulum)?

A

In ER, many enzymes that help transforming chemicals to another form are produced. The metabolism of the chemicals takes place here

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2
Q

Why is cell membrane a good thing in this context (toxicology)?

A

The cell membrane keeps things outside/inside

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3
Q

What is the cell membrane made of?

A 
Lipid bilayer (two layers of phospholipids). 
Outside: sensors (oligosaccharide, glycolipid) that cause a respons if it detects something. 
Inside: protein
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4
Q

What are phospholipids made of?

A

A polar head group (negative or positive) that is hydrophilic and one nonpolar lipid tail that is hydrophobic. These are amphiphilic since they have both hydrophilic (water loving) and lipophilic (fat loving) properties.

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5
Q

What is LD50?

A

Lethal dose to kill 50 % of the population

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6
Q

What does toxicity depend on? With words

A
  1. Molecular structure and chemical mechanism of toxicity

2. The situation where the toxic effect occurs

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7
Q

What does toxicity depend on? Chemically

A
  1. Physical form (low boiling point: more molecules in the air, bad if you inhale them)
  2. Purity (2,4,5-T often contain TCDD which is a very dangerous molecule)
  3. Route of expose (how the chemicals enter our body)
  4. Exposed organism (toxicity of a chemical depends on the organism)
  5. Sex (female, male)
  6. Age (kids: all enzyms has not been fully developed so it might lead to different metabolic pathways, older people: has less functioning metabolic pathways)
  7. Individual markers (each animal is different to another —> metabolism also differs)
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8
Q

What are the routes of exposure? i.e. how does the chemicals get into the body. 6 ways

A
  1. Or-Orl (Oral - food, drinks)
  2. Iv-Ivn (Intravenous - blood circulation)
  3. Ip-Ipr (Intraperitoneal - in abdominal cavity)
  4. In-Ihl (Inhalation - air)
  5. Sc-Scu (Subcutan - under skin)
  6. D-Skn (Dermal - on skin)
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9
Q

What is the typical order in effeciency of the routes of exposure?

A

Ivn>Ihl>Ipr>Scu>Orl>Skn

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10
Q 
What is:
LD?
LC?
TD?
TC?
LDlo or LDlow?
A

LD: lethal dose (mg molecule/kg bodyweight)
LC: lethal concentration (gas %)
TD: toxic dose (how many that get blind etc)
TC: toxic concentration (how many that get blind etc)
LDlo/LDlow: lowest dose that has ever been reported to cause an individual to die - should be lower than LD10

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11
Q

Why do you use lethal concentration and not just lethal dose?

A

It’s hard to know how much dose the animal got: if the chemical is gas it’s hard to say how much the animal inhaled

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12
Q

Toxicological concepts: What are acute and chronic effects?

A

Acute: symptoms comes fast
Chronic: long term effect
For example alcohol: can cause both acute and chronic effects.
- acute: drunk, dizzy, death
- chronic: long time drinking —> damage the liver

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13
Q

Toxicological concepts: What are delayed effects?

A

Symptoms that shows up a long time after.
For example:
- cancer: do not form right after exposure, it is often produced years after. It needs a series of transformed DNA, cells and mutation which takes time

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14
Q

Toxicological concepts: What is reversible and irreversible effects?

A

Reversible effects: effects that will disappear when the molecule is removed
Irreversible effects: damage that won’t disappear even when the chemical is removed

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15
Q

Toxicological concepts: What is local and systemic effects?

A

Local effects: for example, if you get a chemical on your skin and it burns
Systemic effects: chemical will be absorbed by the body and will be transported to the target organ in our body and it will affect our entire body

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16
Q

Toxicological concepts: What is target organ?

A

The organ where the chemical acts/will be affected

17
Q

Toxicological concepts: What is critical concentration? Individual and population

A
  1. Individual critical concentration: the dose/concentration needed to show the symptoms in an individual
  2. Population critical concentration: the dose/concentration needed to show the symptoms in a population. Use LD50, LD10 etc!!! —> Can’t be used for individuals
18
Q

Toxicological concepts: What is metabolic activation/inactivation? In a toxicological context

A

Metabolic activation: by metabolism, a chemical is turned into a more toxic form
Metabolic inactivation: by metabolism, a chemical is turned into a less toxic form

19
Q

Toxicological concepts: What is tolerance?

A

An individual MIGHT develop a resistance toward a chemical. This is because the enzym needed to metabolise the chemical might be more induced by the presence of the chemical —> you produce an enzym that can metabolise these chemicals.
We are not more resistant just because we have worked with chemicals a long time —> need long time exposure, but it’s not reliable/true

20
Q

What is additive effect?

A

When two chemicals act separately with similar effects, doesn’t effect each other.
2+2=4

21
Q

What is synergistic effect?

A

When two chemicals are together and make each other stronger.
2+2=10 “cocktail effect”

22
Q

What is potentiating effect?

A

When one chemical is toxic and one is not, but when they are together —> stronger toxic effect.
0+2=7 “cocktail effect”

23
Q

What are the four antagonistic effects?

A
  1. Functional ant. (Two chemicals have opposite effects —> 2-2=0)
  2. Chemical ant. (Two chemicals react with each other and form an inactive form —> 2+2=1)
  3. Dispositional ant. (If you eat something toxic, charcoal can absorb the toxic and extract it from your blood stream —> 2+2=1)
  4. Receptor ant. (A chemical that bind to and blocks a receptor, to block/dampen a biological respone, rather than activate it like an agonist)
24
Q

Describe synergistic effects using CHCl3 and ethanol.

A

Synergistic effect: 2+2=10.
Both ethanol and chloroform is metabolized by the same enzyme —> more ethanol allows a faster metabolic activation of chloroform—> will cause a stronger toxic effect.

25
Q

Decribe potentiating effect using iso-propanol and chloroform.

A

Potentiating effect: 0+2=7.
If iso-propanol is present with chloroform, it can induce the production of the enzyme used to metabolise chloroform—> will produce more of the toxic form.
Iso-propanol: non-toxic —> but can make the toxic effect of chloroform much stronger.

26
Q

What is specific and non-specific toxicity?

A

???

27
Q

What is selective and non-selective toxicity?

A

Selective compounds: are more toxic for a certain organism (organ, tissue, cell type, animals, plants)
Non-selective compounds: are equitoxic, is the same for all targets

28
Q

Selective and non-selective toxicity: penicillin G, norbormide, glyphosate

A

Penicillin G: very toxic for bacteria but not for animals (selective: bacteria)
Norbormide: very toxic for rodents but not for cats and dogs (selective: rodents)
Glyphosate: kill plants effectively, but isn’t that dangerous to animals (selective for plants over animals, non-selective for all plants)

Selective/non-selective toxicity is relative - it depends on the range of targets we are talking about

29
Q

When doing animal tests, do you want large and few doses or small and many doses?

A

As few and large doses as possible

30
Q

What is carcinogenic and teratogenic?

A

Carcinogenic: ability or tendency to produce cancer
Teratogenic: malfunction/abnormalities.
- teratogens are substances that may cause birth defects via toxic effect on an embryo or fetus (e.g. alcohol) - could be born wihtout legs etc

Environmental Chemistry (6 decks)

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