Drugs of abuse appear in NEET as terminology-heavy recall questions. The trap is not calculation — it is confusing the drug category, the source plant/chemical, and the pharmacological effect. Get the classification grid right and these are free marks.
Three drug categories NCERT emphasises (Class 12 Biology, Chapter 7, page 170):
Opioids bind to opioid receptors in the CNS, producing sedation, pain relief, and euphoria. Heroin (diacetylmorphine, chemically derived from morphine extracted from Papaver somniferum — the opium poppy) is the most commonly tested opioid. It is smoked or injected intravenously. Morphine itself is a medically used analgesic that becomes an abuse substance when taken without prescription.
Cannabinoids interact with cannabinoid receptors in the brain. The source is Cannabis sativa — the plant yields marijuana (flower tops), hashish (resin from flower tops), and charas. These affect cardiovascular system function and are generally taken by inhalation or oral ingestion.
Coca alkaloids (cocaine) are obtained from Erythroxylum coca. Cocaine stimulates the CNS by interfering with dopamine transporter function, producing intense euphoria followed by depression. It is typically snorted; it can also be injected. NCERT lists it alongside the category of stimulants that includes amphetamines and caffeine — but cocaine's plant source is the high-frequency NEET ask.
Addiction mechanism — the NEET-relevant summary: Repeated use → tolerance (need higher dose for same effect) → psychological and physical dependence → withdrawal symptoms on cessation. NCERT stresses that adolescents are vulnerable due to peer pressure, curiosity, and the perception of enhanced academic or athletic performance.
Watch-out: NEET distractors swap source plants across categories — Papaver offered for cocaine, Erythroxylum offered for opioids. Lock the grid: opium poppy → opioids, cannabis → cannabinoids, coca plant → cocaine.
Select an option to see the explanation. Wrong answers show why your choice was tempting — and name the exact trap it exploits.
Heroin (diacetylmorphine) is chemically derived from which natural substance?
Which plant is the source of cannabinoids such as marijuana and hashish?
Cocaine, a CNS stimulant drug of abuse, is obtained from:
An adolescent develops tolerance to a drug, requiring progressively higher doses to achieve the same effect. This phenomenon is a hallmark of:
A person who abruptly stops taking an opioid after prolonged use experiences nausea, anxiety, and tremors. This clinical presentation is best described as:
A student claims that hashish and charas are obtained from different plant species. Which correction is appropriate?
Among the following, which correctly matches the drug category with its primary pharmacological mechanism?
NCERT lists peer pressure, curiosity, and desire for enhanced performance as factors making adolescents vulnerable to drug abuse. Which of the following interventions aligns with the preventive measures described in NCERT?
Given
A NEET question states: "Diacetylmorphine is obtained from which of the following?" Options: (A) *Erythroxylum coca*, (B) *Cannabis sativa*, (C) *Papaver somniferum*, (D) *Atropa belladonna*.
Required
Identify the correct source plant for diacetylmorphine.
Concept
Diacetylmorphine is the chemical name for heroin. Heroin is synthesised by acetylation of morphine. Morphine is a natural opioid alkaloid extracted from the latex of the opium poppy.
Formula
No formula required — this is a recall-classification question.
Substitution
Diacetylmorphine → heroin → derived from morphine → morphine comes from *Papaver somniferum*.
Calculation
No arithmetic. The chain is: diacetylmorphine = heroin = acetylated morphine. Morphine source = *Papaver somniferum*.
Final answer
**(C) *Papaver somniferum***
Common trap
The most common distractor here is *Erythroxylum coca* (option A) — students who have memorised that cocaine is also a drug of abuse sometimes swap the plant source. Lock the pairing: coca plant → cocaine; opium poppy → opioids.
Similar NEET-style question
"Which of the following is the source of charas and hashish?" (A) *Papaver somniferum*, (B) *Erythroxylum coca*, (C) *Cannabis sativa*, (D) *Datura stramonium*. Answer: (C). Same distractor pattern — plant-source swap. ---
Opioids (heroin, morphine — analgesic); cannabinoids (THC — marijuana); cocaine (CNS stimulant); coca alkaloids; tobacco (nicotine — addictive). Withdrawal symptoms; tolerance; psychological/physical dependence.
-- NCERT Class 12 Biology, Ch. 7, p. 170These are the exact patterns that cause wrong answers in NEET. Each trap includes when it triggers and how to avoid it.
Category: Similar Terms
ELISA = screening (cheap, sensitive); Western blot = confirmation. CD4+ T cell count tracks disease progression.
Question on which test confirms HIV vs which monitors progression.
ELISA first (screening); Western blot confirms; CD4+ count = monitoring marker (<200/µL = AIDS).
Category: Similar Terms
Active: own immune response (vaccination, infection). Passive: pre-formed antibodies received (colostrum, antiserum injection).
Question on immunity type from vaccination, antiserum, mother's milk.
Active = body produces; passive = body receives. Vaccination → active. Mother's milk → passive (IgA).
Root cause: term confusion
Vaccination = ACTIVE (body produces antibodies in response to antigen). Antiserum = passive. Maternal IgA in milk = passive.
Root cause: term confusion
Anopheles = vector (transmits). Plasmodium = causative agent (causes disease). Female Anopheles bite is the transmission route.
29 questions from NEET 2020, 2021, 2022, 2023, 2024, 2025. Answers verified against NTA official keys.
Streptokinase produced by bacterium Streptococcus is used for
The capacity to generate a whole plant from any cell of the plant is called:
Which one of the following is NOT an advantage of inbreeding?
Identify the asexual reproductive structure associated with Penicillium :
Select the incorrect statement with respect to acquired immunity.
Which of the following plants is monoecious? (b) Plant tissue culture (ii) Pomato
Recurring question shapes from past papers. Each pattern shows why wrong options look tempting.
active vs passive immunity confusion
Vaccination triggers the body to produce its own antibodies (active immunity), but students interpret 'given externally' as passive. Passive immunity (antiserum, colostrum IgA from mother's milk) provides preformed antibodies with no immune response from the recipient. Questions that pair vaccination, antiserum, and colostrum expose students who cannot classify by mechanism rather than by route of administration.
vector vs causative agent confusion
Questions name both the vector (organism that transmits) and the causative agent (organism that causes disease) as answer options. Students who associate 'Anopheles = malaria' select Anopheles as the causative agent rather than recognising it as the vector; Plasmodium is the causative agent. The distinction -- vector transmits, causative agent infects -- is lost when both options are plausible from partial recall.
microbe product pair swap
Match-list questions pair 10 or more microbe names with industrial or household products. Students confuse Lactobacillus (lactic acid fermentation, curd) with Saccharomyces cerevisiae (ethanol, bread), or Aspergillus niger (citric acid) with Clostridium butylicum (butyric acid). Partial recall of one-to-one mappings produces swapped pairs, especially when two products share the same chemical class.
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