Toxicology MCQs

This free quiz test on toxicology will help you to prepare for competitive exams or interviews.

1 / 20

The effective dose is best described as which of the following:

The dose at which 50 % of all test animals die

The dose at which some of the animals demonstrate a response to the chemical

The dose at which all of the animals demonstrate a response to the chemical

The dose at which 50 % of all test animals demonstrate a response to the chemical

2 / 20

The LD50 is best described as which of the following:

The dose at which 50 % of all test animals die

The dose at which 50 % of the animals demonstrate a response to the chemical

The dose at which all of the test animals die

The dose at which at least one of the test animals dies

3 / 20

Which of the following are common end points:

Death

No Observable Effect Level

No Observable Adverse Effect Level

Lowest Observable Adverse Effect Level

All of the above

4 / 20

The TD1/ED99 is called:

Margin of safety

Therapeutic index

Potency ratio

Efficacy ratio

5 / 20

A U-shaped graded toxicity dose-response curve is seen in humans with:

Pesticides

Sedatives

Opiates

Vitamins

6 / 20

The LD50 is calculated from:

A quantal dose-response curve

A hormesis dose –response curve

A graded dose-response curve

A log-log dose-response curve

7 / 20

The most rapid exposure to a chemical would occur through which of the following routes:

Oral

Subcutaneous

Inhalation

Intramuscular

8 / 20

The use tamoxifen in certain breast cancer is an example of:

Dispositional antagonism

Chemical antagonism

Receptor antagonism

Functional antagonism

9 / 20

The use of charcoal to prevent the absorption of diazepam is an example of:

Dispositional antagonism

Chemical antagonism

Receptor antagonism

Functional antagonism

10 / 20

The use of antitoxin in the treatment of snakebite is an example of:

Dispositional antagonism

Chemical antagonism

Receptor antagonism

Functional antagonism

11 / 20

If two organophosphate insecticides are absorbed into an organism, the result will be:

Additive effect

Synergestic effect

Potentiation

Substraction effect

12 / 20

If propyl alcohol and carbon tetrachloride are chronically absorbed into an organism, the effect on the liver would be:

Additive effect

Synergesic

Potentiation

Substraction effect

13 / 20

The organs least involved in systemic toxicity are:

Brain and peripheral nerves

Muscle and bone

Liver and kidney

Hematopoietc system and lungs

14 / 20

The most common target organ of toxicity is the:

Heart

Lungs

CNS

Skin

15 / 20

Which of the following toxicity can occur due to single exposure?

Acute toxicity

Sub-acute toxicity

Sub-chronic toxicity

Chronic toxicity

16 / 20

Which of the following is NOT an initiating event in carcinogenesis?

DNA adduct formation

DNA strand breakage

mutation of proto-oncogenes

oxidative damage of DNA

mitogenesis

17 / 20

The phrase that best defines "toxicodynamics" is the:

linkage between exposure and dose

linkage between dose and response

dynamic nature of toxic effects among various species

dose range between desired biological effects and adverse health effects

loss of dynamic hearing range due to a toxic exposure

18 / 20

The reference dose (RfD) is generally determined by applying which of the following default procedures?

an uncertainty factor of 100 is applied to the NOAEL in chronic animal studies

a risk factor of 1000 is applied to the NOAEL in chronic animal studies

a risk factor of 10,000 is applied to the NOAEL in subchronic animal studies

an uncertainty factor between 10,000 and 1 million is applied to the NOEL from chronic animal studies

multiplying the NOAEL from chronic animal studies by 100

19 / 20

Allergic contact dermatitis is:

a non-immune response caused by a direct action of an agent on the skin

an immediate type I hypersensitivity reaction

a delayed type IV hypersensitivity reaction

characterized by the intensity of reaction being proportional to the elicitation dose

20 / 20

A toxic substance produced by biological system is specially referred to as a:

Toxicant

Toxin

Xenobiotic

Poison

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The average score is 44%

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