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MB prep: Biochemistry. > Xenobiotics > Flashcards

Flashcards in Xenobiotics Deck (48)
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1
Q

what is a xenobiotic

A

A xenobiotic is a compound that is foreign to the body. Xenobiotics include food additives, insecticides, poisons, toxins, certain drugs, chemicals, environmental pollutants, pesticides, and other foreign substances

2
Q

give examples of xenobiotics

A

Xenobiotic includes
-food additives,
-poisons,
-toxins,
-certain drugs,
-chemicals,
-environmental pollutants,
-pesticides and
-other foreign substances.

3
Q

what is an environmental pollutant

A

Any substance present in the environment, which may produce abnormality in metabolism or alter the well being of organism is called an environmental pollutant

4
Q

what is a poison

A

a poison is a substance which causes death or harm if introduced in the living body or brought into contact with parts of the body

5
Q

what is the lethal dose of cyanide

A

1mg/kg of body weight

6
Q

what is the lethal dose of morphine

A

25mg/kg of body weight

7
Q

what is the lethal dose of aspirin

A

500mg/kg of body weight

8
Q

what is the lethal dose of ethyl alchohol

A

10g/kg of body weight

9
Q

list some environmental pollutants

A

-pollutants and insecticide
-occupational and industrial hazards
-air pollutants
-toxins in food and food processing
-corrosives
-irritants

10
Q

comment on pollutants and insecticide

A

-DDT (dichlorodiphenyI trichloro ethane)- It is fat soluble and deposited in the adipose tissue. It is not excreted. Thus concentration inside the body goes on increasing.

-Organophosphorus compounds and organocarbamates are the common pesticides and organo sulfur compounds (dithiocarbamates) are fungicides. Organophosphorus compounds, parathion and malathion are powerful neurotoxic agents.

11
Q

comment on why DDT (dichlorordiphenyl trichloroethane) is a pollutant

A

it is fat-soluble and deposited in the adipose tissue. It is not excreted. Thus concentration inside the body goes on increasing

12
Q

comment on organophosphorus compounds

A

examples are:
-parathion
-malathion

They are powerful neurotoxic agents

13
Q

comment on the organocarbamates

A

they are common pesticides

14
Q

comment on the organosulfur compounds

A

-They are also called dithiocarbamates

-They are fungicides

15
Q

comment on occupational and industrial hazards under environmental pollutants

A

-Polychloro-biphenyls- bisphenols (plastic containers), vinyl phenols (PVC pipes)

-Freon (CFCl2) and chlorofluoromethane (CFCI3) are used in refrigerators and spray-cans.

-Methanol- an organic solvent widely used in paints and antifreeze

=>Air Pollutants
-Natural sources- volcanic eruption, forest fires, dust storms and air borne particles.
-Artificial sources- emissions from automobiles, industry and power plants. These are carbon dioxide, carbon monoxide, hydrocarbons. Oxides of nitrogen, oxides of sulfur and
lead
-The poisonous mixture of smoke, fog, air and other chemicals is called smog.
-Cigarette smoking

16
Q

comments on air pollutants under occupational and industrial hazards

A

=>Air Pollutants.

-Natural sources- volcanic eruption, forest fires, dust storms and air borne particles.

-Artificial sources- emissions from automobiles, industry and power plants. These are carbon dioxide, carbon monoxide, hydrocarbons. Oxides of nitrogen, oxides of sulfur and
lead

-The poisonous mixture of smoke, fog, air and other chemicals is called smog.

-Cigarette smoking.

17
Q

what are some artificial sources of air pollution

A

-emissions from automobiles and industry and power plants. These are:
- carbon dioxide,
- carbon monoxide,
- hydrocarbons
- Oxides of nitrogen,
- Oxides of sulfur and lead

18
Q

what is a smog

A

Smog is a poisonous mixture of:
-smoke
-air
-fog
-other chemicals

19
Q

what are common industrial pollutants

A

-Acid fumes- fertilizers, chlorinated organic compounds, dyes, explosives, plastics

-Cyanides- electroplating, extraction of gold or silver, fumigants

-Formaldehyde- resins, rubber, laboratory works, urethane foam

-Halides- Bleaching in pulp, paper textile industry, synthetic rubber, plastics

-Isocyanates- polyurethane foams, plastics, adhesives, surface coatings

-Nitrogen dioxide- metal etching, explosives, welding, a byproduct of burning fossil fuels

-Sulphur dioxide- coating of nonferrous metals, food processing, burning of fossil fuels

20
Q

comment on isocyanate as a industrial pollutant

A

-polyurethane foams,
-plastics,
-adhesives,
-surface coatings

21
Q

comment on sulphur dioxide as an industrial pollutant

A

-coating of nonferrous metals,
-food processing,
-burning of fossil fuels

22
Q

comment on nitrogen dioxide as an industrial pollutant

A

-metal etching,
-explosives,
-welding,
-byproduct of burning fossil fuels

23
Q

comment on halides as an industrial pollutant

A

-Bleaching in pulp,
-paper textile industry,
-synthetic rubber,
-plastics

24
Q

what are some cyanides in industrial pollutants

A

-electroplating,
-extraction of gold or silver,
-fumigants

25
Q

what are some formaldehyde in industrial pollutants

A

-resins,
-rubber,
-laboratory works,
-urethane foam

26
Q

what are some acid fumes in industrial pollutants

A

-fertilizers,
-chlorinated organic compounds,
-dyes,
-explosives,
-plastics

27
Q

what are the toxins in food and food processing

A

-Alkaloids- Some mushrooms contain poisonous alkaloids. In small quantities the produce nausea, diarrhea, etc. In large quantities, it may produce acute necrosis of liver and death may result.

-Adulterant- lathyrism, argamone oil

-Food additive- e.g. monosodium glutamate (aginomoto)- it deteriorate mental alertness

-Food cyanide poisoning- cyanogenic glucosides, linamarin and lotautralin

28
Q

what are the alkaloids as toxins in foods and food processing

A

Some mushrooms contain poisonous alkaloids. In small quantities the produce nausea, diarrhea, etc. In large quantities, it may produce acute necrosis of liver and death may result.

29
Q

what are the aldulterants that are toxins on food and food processing

A

-Lathyrism
-Argamone oil

30
Q

what food additives are toxins in food and food processing

A

-Monosodium glutamate (aginomoto), which deteriorates mental alertness

31
Q

what xenobiotics contribute to food cyanide poisoning

A

-cyanogenic glucosides,
-linamarin and
-lotautralin

32
Q

what are the corrosives

A

These are:
- strong acids (sulfuric acid, hydrochloric acid);
- strong alkalies (sodium hydroxide, ammonia); and
- salts (zinc chloride, potassium chromate).

33
Q

what are the salts that are corrosives

A

-zinc chloride
-potassium chromate

34
Q

what are the strong alkalies that are corrosives

A

-sodium hydroxide
-ammonia

35
Q

what are the strong acids that are corrosives

A

-sulfuric acid
-hydrochloric acid

36
Q

what are the irritants

A

=>Important chemical irritants are:
- phosphorus,
- chlorine,
- bromine
- iodine.

=>Metallic irritants are:
- arsenic,
- antimony,
- mercury,
- copper,
- lead,
- zinc
- silver.

=>Organic irritants from plants include:
- castor,
- croton,
- calotropis.

37
Q

what are the chemical irritants

A

-phosphorus
-bromine
-chlorine
-iodine

38
Q

what are the organic irritants

A

They are derived from plants:
-Castor
-Calotropis
-Croton

39
Q

what are the organic irritants

A

They are derived from plants:
-Castor
-Calotropis
-Croton

40
Q

what are the metallic irritants

A

-arsenic
-copper
-mercury
-silver
-antimony
-lead
-zinc

41
Q

what is metabolism of xenobiotics

A

This refers to the detoxification of toxic substances in the body

42
Q

what is detoxification

A

The biochemical processes whereby the noxious substances are rendered less harmful and more water-soluble are known as DETOXIFICATION.

43
Q

WHAT IS BIOTRANSFORMATION

A

biotransformation is the process whereby a substance is changed from one chemical to another by a chemical reaction within the body.

44
Q

why is biotransformation not synonymous with detoxification

A

This is because in some cases, the metabolites are more toxic than the parent substance.

EXAMPLE: vinyl chloride is converted to vinyl chloride epoxide, which covalently binds to DNA and RNA, this is a step leading to cancer of the liver.

45
Q

give an example pf why biotransformation is not synonymous with detoxification

A

vinyl chloride is converted to vinyl chloride epoxide, which covalently binds to DNA and RNA, this is a step leading to cancer of the liver.

46
Q

what is a phase 1 reaction

A

-Phase 1 is the alteration of the foreign molecule, so as to add a functional group, which can be conjugated in phase 2.

-Phase 1 reactions result in the formation of compounds with decreased
toxicity (detoxification). Sometimes this may result in increased toxicity (entoxification), e.g. methanol to formic acid.

=>Phase 1 metabolism includes:
- oxidation,
- reduction,
- hydrolysis and
- hydration reactions as well as other rarer miscellaneous reactions.
Oxidation is considered separately because of its importance and the diversity of reactions performed by this enzyme system.

47
Q

in what case does the phase 1 reaction of xenobiotic metabolism result in increased toxicity

A

methanol to formic acid

48
Q

what reactions are under phase 1 metabolism

A
  • oxidation,
  • reduction,
  • hydrolysis and
  • hydration reactions as well as other rarer miscellaneous reactions.