Forensic Toxicology
Forensic Toxicology Quiz Crafted by -
Sudhanshu Shekher Tiwari
Assistant Professor
School of Forensic Science and Risk Management
Rashtriya Raksha University, Gujarat.
Introduction to Forensic Toxicology
Forensic toxicology is the use of toxicology and disciplines such as analytical chemistry, pharmacology and clinical chemistry to aid medical or legal investigation of death, poisoning, and drug use. The primary concern for forensic toxicology is not the legal outcome of the toxicological investigation or the technology utilized, but rather the obtainment and interpretation of results. A toxicological analysis can be done to various kinds of samples. A forensic toxicologist must consider the context of an investigation, in particular any physical symptoms recorded, and any evidence collected at a crime scene that may narrow the search, such as pill bottles, powders, trace residue, and any available chemicals. Provided with this information and samples with which to work, the forensic toxicologist must determine which toxic substances are present, in what concentrations, and the probable effect of those chemicals on the person.
Here is the List of Questions with Answers along with explanation
Que 1. Which of the following instrument is used to identify the organic
drugs?
(A) Infra-red spectrophotometer
(B) Polymerase chain reaction
(C) Atomic absorption spectrophotometer
(D) Automatic blood analyzer
Answer: (A) Infra-red spectrophotometer
Explanation: Almost any compound having covalent bonds absorbs various frequencies of electromagnetic radiation in the infrared region of the electromagnetic spectrum. This region lies at wavelength longer than those associated with visible light, which range from approximately 400 to 800 nm, but lies at wavelengths shorter than those associated with microwaves, which are longer than 1 mm. For chemical purposes, we are interested in the vibrational portion of the infrared region. It includes radiations with wavelengths between 2.5 μm and 25 μm. In the early use of IR spectroscopy in 1882, William Abney managed to identify 52 benzene derivatives from the IR spectroscopy. IR spectroscopy is used to see the the functional group in the molecule as the bonds vibrates at certain wavenumber and it only vibrate at only certain allowable frequencies.
Que 2. Which of the following preservatives is used to preserve the blood in case of alcohol poisoning?
(A) EDTA
(B) Heparin
(C) Sodium fluoride
(D) Sodium chloride
Answer: (C) Sodium fluoride
Explanation: Sodium Fluoride prevents the breakdown of blood glucose (a process called glycolysis). The glucose concentration in NaF remains stable up to three days. Glucose breaks down to pyruvate and lactate with the sequential implementation of various enzymatic reactions. Sodium fluoride inhibits some enzymatic reactions, including the conversion of phosphoglycerate to phosphoenolpyruvate, and prevents glycolysis.
Que 3. Which of the following drugs of abuse is over 100 times as potent as morphine ?
(A) Fentanyl
(B) Psilocybin
(C) Mescaline
(D) Mandrex
Answer: (A) Fentanyl
Explanation: Fentanyl is a powerful synthetic opioid
that is similar to morphine but is 50 to 100 times more potent. It is a
prescription drug that is also made and used illegally. Like morphine, it is a
medicine that is typically used to treat patients with severe pain, especially
after surgery. It is also sometimes used to treat patients with chronic
pain who are physically tolerant to other opioids. Tolerance occurs when
you need a higher and/or more frequent amount of a drug to get the desired
effects.
Que 4. Toddy
is manufactured from which of the following?
(A) Rice
(B) Palm
(C) Wheat
(D) Molasses
Answer: (B) Palm
Explanation: The toddy palm is native to India and
Southern Pakistan, where it grows both wild and cultivated. It thrives in hot,
low wastelands. The toddy palm gets its name from the popular Indian drink
called toddy that is made of its fermented sap. The sap is very sweet and is
ingested in both alcoholic and non-alcoholic forms. It will start to ferment
just a few hours after it’s harvested, so to keep it non-alcoholic, it’s often
mixed with lime juice.
Que 5. Pycnometer method is used to estimate which of the following property of alcoholic beverage?
(A) Ethyl alcohol content
(B) Total acidity
(C) Volatile acidity
(D) Higher alcohol content
Answer: (A) Ethyl alcohol content
Explanation: The proof of an alcoholic
beverage is a measurement of its ethanol content. The proof of spirit and
wine is defined as the percentage by volume of ethanol. The traditional method
for determination of proof uses a pycnometer or a small, accurately
graduated hydrometer. Recently, the European Community has adopted a
reference method for ethanol determination in spirits, based on two steps. The
first step is a prescribed distillation stage and the second step allows a
choice from three different methods of measuring the density of the distillate:
(1) pycnometry: time consuming and susceptible to error; (2) electronic
densimetry: measurement of the oscillations of a
vibrating U-tube, this method is simple and fast; (3) densimetry using
hydrostatic balance: this method is also fast with the new generation of
instrumentation.
Measuring the density followed by conversion into alcohol concentration using official alcohol tables is an officially recognized method for alcohol determination in distillates. Accepted instruments for measuring the density for subsequent alcohol determination include pycnometers, hydrometers, and digital density meters.
Que 6. Alcohol
is oxidised to acetaldehyde in the liver by
(A) Peroxidase
(B) Glyoxylase
(C) Phosphoglucomutase
(D) Alcohol dehydrogenase
Answer: (D) Alcohol dehydrogenase
Explanation: The mammalian
alcohol dehydrogenases (ADHs) are a family of enzymes that catalyze
the oxidation and reduction of a wide variety of alcohols
and aldehydes. They are abundant in the liver but are present to different
extents in other tissues. The individual members of this family have different
but overlapping substrate specificities, and probably play a general
detoxifying role. They have attracted considerable interest due to their key
role in the metabolism of ethanol (beverage alcohol), which modulates the
effects of ingested ethanol on the body. Individual differences
in ADH isozymes and expression affect risk for alcoholism,
tissue damage, and developmental abnormalities including fetal alcohol
spectrum disorders. In this chapter, we focus primarily on the
human ADHs and their role in the metabolism of endogenous and dietary
alcohols, including ethanol.
Que 7. Parathion is metabolised to which of the following?
(A) p-nitrophenol and diethyl phosphate
(B) o-nitrophenol and ethyl phosphate
(C) o-nitrophenol and methyl phosphate
(D) m-nitrophenol and dimethyl phosphate
Answer: (A) p-nitrophenol and diethyl phosphate
Explanation: Parathion is a deep brown to yellow
liquid with a faint odor of garlic. It is an organic phosphate insecticide
which acts as an inhibitor of cholinesterase, and as such it is highly toxic by
all routes of exposure. It may be found as a liquid or as a dry mixture where
the liquid is absorbed onto a dry carrier. Major metabolic products
/of parathion metabolism in animals are 4-nitrophenyl
phosphate, diethyl hydrogen phosphorothionate, diethyl hydrogen
phosphate & p-nitrophenol. The reaction resulting in the formation
of diethyl hydrogen phosphorothionate & p-nitrophenol requires
the same cofactors such as oxygen & reduced
nicotinamide adenine dicucleotide , as the biotransformation
of parathion into 4-nitrophenyl phosphate
Que 8. Dhatura poisoning resembles with which of the following?
(A) Kuchala poisoning
(B) Opium poisoning
(C) Atropine poisoning
(D) Rati poisoning
Answer: (B) Opium poisoning
Explanation: Datura stramonium (DS), known as Jimson
weed is a wild-growing herb. The entire plant especially the foliage and seeds,
is toxic due to its content of tropane alkaloids. The contained atropine,
L-hyoscyamine and L-scopolamine cause anticholinergic syndrome, which results
from the inhibition of central and peripheral muscarinic
neurotransmission
Que 9. Which one of the following is an active metabolite of chloral hydrate?
(A) Chlorpromazine
(B) Trichloroethanol
(C) Dexmedetomidine
(D) Methylphenidate
Answer: (B) Trichloroethanol
Explanation: Chloral hydrate is metabolized by the
liver and erythrocytes to form trichloroethanol (an active
metabolite). The reduction of chloral hydrate
to trichloroethanol (the major metabolite) is catalyzed by alcohol
dehydrogenase and other enzymes. A small but variable amount of chloral hydrate
and a larger portion of trichloroethanol are oxidized
to trichloroacetic acid (an inactive metabolite), mainly in the liver
and kidneys. Trichloroethanol may also be conjugated
with glucuronic acid to form trichloroethanol
glucuronide (urochloralic acid), an inactive metabolite. The quantities of
metabolites excreted in the urine appear to be quite variable not only between
different individuals but may even vary in the same individual on different
days.
Que 10. Morphine dependence is best characterised by which of the following?
(A) Constricted pupils
(B) Masked face
(C) Jaundice
(D) Anorexia
Answer: (D) Anorexia
Explanation: Morphine dependence can actually make the body function differently than
it did without morphine. This is defined as a physical dependence and
can be characterized by the lack of chemical reaction in the brain due to
suddenly removing morphine from a system that has become dependent on the drug.
Morphine can also cause a psychological dependence when taken for
prolonged periods of time. A psychological dependence is characterized by an
individual thinking they need to take a drug in order to function properly,
even though there is no actual chemical or physical need for it. When an
individual develops a psychological dependence before a physical dependence on
morphine, it can often lead to a more aggressive dependency or addiction.
Que 11. Which
enzyme regulates the metabolism of opiates?
(A) SULT 2
(B) CYP 2D6
(C) COMT
(D) MT
Answer: (B) CYP 2D6
Explanation: Opioids undergo phase 1 metabolism by
the CYP pathway, phase 2 metabolism by conjugation, or both. Phase 1 metabolism
of opioids mainly involves the CYP3A4 and CYP2D6 enzymes. The CYP3A4 enzyme
metabolizes more than 50% of all drugs; consequently, opioids metabolized by
this enzyme have a high risk of drug-drug interactions. The CYP2D6 enzyme
metabolizes fewer drugs and therefore is associated with an intermediate risk
of drug-drug interactions. Drugs that undergo phase 2 conjugation, and
therefore have little or no involvement with the CYP system, have minimal
interaction potential.
Que 12. Consumption of which of the following causes blindness?
(A) Amphetamine
(B) Morphine
(C) Atropine
Answer:
Explanation: As little as 10 mL of
pure methanol when drunk is metabolized into formic acid, which
can cause permanent blindness by destruction of the optic
nerve. 15 mL is potentially fatal, although the median lethal dose is typically
100 mL (3.4 fl oz) (i.e. 1–2 mL/kg body weight of pure methanol).
Que 13. Methanol
toxicity is due to the formation of which of the following?
(A) Formic acid due to the action of dehydrogenase enzyme in liver
(B) Formic acid due to the action of dehydrogenase enzyme in kidney
(C) Formic acid due to the action of protease enzyme in liver
Answer: (A) Formic acid due to the action of dehydrogenase enzyme in liver
Explanation: As a clear,
colourless, volatile liquid with a weak odour, methanol is difficult to
differentiate from other forms of alcohols such as ethanol.4,5 Methaanol
is rapidly absorbed not only after oral ingestion but by inhalation or after
cutaneous exposure and becomes oxidised in the liver to formaldehyde and to
formic acid, metabolites which are more toxic than methanol itself and which
inhibit mitochondrial ATP production. Methanol poisoning can be life
threatening and blinding. Early ocular symptoms and signs include photophobia,
blurred vision, and painful eye movements as well as sluggish pupil reactions,
reduced visual acuity, and optic disc oedema with tortuous retinal vessels.
Histopathologically, circumscribed myelin damage behind the lamina cribrosa of
the optic nerve has been reported.6 The electrophysiological changes
following acute methanol ingestion suggest that methanol affects
photoreceptors, Muller cells, and the retrolaminar portion of the optic
nerve.7 Treatment is by drug elimination (for example, haemodialysis) and
inhibition of metabolism of methanol to toxic formic acid by competitive
inhibition of the enzyme alcohol dehydrogenase (ethyl alcohol or fomepizole
Que 14. Kozelaka and Hine method is used for the quantitative estimation of
(A) Formic acid due to the action of dehydrogenase enzyme in liver
(B) Opium
(C) Cocaine
(D) Cannabis
Answer: (A) Formic acid due to the action of dehydrogenase enzyme in liver
Que 15. The
following is a poisonous mushroom species:
(A) Amanita phalloides
(B) Morchellaesculenta
(C) Boletus edulis
(D) Cantharelluscibarius
Answer: (A) Amanita phalloides
Explanation: Amanita
phalloides (the death cap mushroom) contains the most deadly toxin (the
amanita toxin) of all poisonous mushrooms. Reported mortality
after ingestion of Amanita phalloides ranges from 25% to
50%.26 The lethal dose of amanita toxin is 0.1 mg/kg body weight and
therefore severe poisoning can occur with as little as 5 to 7 mg of amanita
toxin, an amount that can be present in a single mushroom.26 The amanita
toxin is eliminated by the kidneys and usually is undetectable in the plasma 48
hours after ingestion.