Biochemistry
1 questionsWhich of the following acids is MOST commonly used as a reagent in medical laboratory analytical procedures?
NEET-PG 2015 - Biochemistry NEET-PG Practice Questions and MCQs
Question 671: Which of the following acids is MOST commonly used as a reagent in medical laboratory analytical procedures?
- A. Nitric acid is used in chemical analysis.
- B. Carbolic acid is used as a disinfectant.
- C. Oxalic acid is used in various laboratory applications.
- D. Sulphuric acid is used in various laboratory processes. (Correct Answer)
Explanation: ***Sulphuric acid*** is the most commonly used acid in medical laboratory analytical procedures. - **Sulfuric acid (H₂SO₄)** is a strong mineral acid with the **widest range of applications** in clinical and research laboratories - Used extensively as a **catalyst and reagent** in numerous analytical procedures including **protein digestion**, **Kjeldahl nitrogen estimation**, and **enzymatic assays** - Essential in **sample preparation** for heavy metal analysis and trace element detection - Utilized in **deproteinization** procedures and various **colorimetric assays** - Its strong **dehydrating properties** make it valuable in multiple biochemical protocols *Nitric acid* - **Nitric acid (HNO₃)** is primarily used for **acid digestion** of samples in trace element analysis - Strong **oxidizing agent** but has more **specialized applications** compared to sulfuric acid - More commonly used in **environmental and toxicology testing** than routine clinical biochemistry - Its highly **corrosive and oxidizing nature** limits its use in routine procedures *Carbolic acid* - **Carbolic acid (phenol/C₆H₅OH)** is technically not a mineral acid but a weak organic acid - Historically used as an **antiseptic and disinfectant** (Lister's antiseptic) - Modern laboratory use is **limited** to specific applications like **phenol-chloroform extraction** in molecular biology - Due to **toxicity concerns**, largely replaced by safer alternatives in routine disinfection *Oxalic acid* - **Oxalic acid (C₂H₂O₄)** is an organic dicarboxylic acid with **specialized applications** - Used in **decalcification of bone samples** for histopathology - Functions as a **reducing agent** in specific analytical procedures - Not a routine reagent in general medical laboratory practice compared to sulfuric acid
Forensic Medicine
2 questionsWhat is the scientific name of the plant commonly known as Thorn apple?
Which of the following is an opioid derived from morphine?
NEET-PG 2015 - Forensic Medicine NEET-PG Practice Questions and MCQs
Question 671: What is the scientific name of the plant commonly known as Thorn apple?
- A. Datura stramonium (Correct Answer)
- B. Nux vomica
- C. Papaver somniferum
- D. Cannabis sativa
Explanation: ***Datura stramonium*** - This is the correct **scientific name** for the plant commonly known as **Thorn apple** or Jimsonweed. - *Datura stramonium* is known for its **anticholinergic** properties due to alkaloids like atropine, scopolamine, and hyoscyamine. *Nux vomica* - This plant is scientifically known as *Strychnos nux-vomica* and is a source of **strychnine** and brucine. - It is known for its **CNS stimulant** and convulsant effects, and is not referred to as Thorn apple. *Papaver somniferum* - This is the **opium poppy**, famous for producing **opium**, from which morphine, codeine, and heroin are derived. - Its common name is not Thorn apple, and its effects are primarily **analgesic** and sedative. *Cannabis sativa* - This plant is commonly known as **marijuana** or hemp, and it produces cannabinoids such as THC and CBD. - It is recognized for its **psychoactive** and medicinal properties, and is not related to Thorn apple.
Question 672: Which of the following is an opioid derived from morphine?
- A. Cocaine
- B. Dhatura
- C. Cannabis
- D. Heroin (Correct Answer)
Explanation: ***Heroin*** - Heroin (**diacetylmorphine**) is synthesized from **morphine** through a simple acetylation process. - Morphine, an **opiate**, is naturally derived from the opium poppy. *Cocaine* - **Cocaine** is a powerful stimulant and local anesthetic derived from the **coca plant**. - It is a **naturally occurring alkaloid** but is not structurally or functionally related to opioids. *Dhatura* - **Dhatura** (Datura stramonium) contains **tropane alkaloids** like scopolamine and atropine, which have anticholinergic effects. - It is not an opioid and does not interact with opioid receptors. *Cannabis* - **Cannabis** (marijuana) contains **cannabinoids**, primarily THC, which act on cannabinoid receptors in the brain. - It is distinctly different from opioids in its chemical structure, mechanism of action, and effects.
Microbiology
1 questionsWhich of the following statements about paramyxoviruses is false?
NEET-PG 2015 - Microbiology NEET-PG Practice Questions and MCQs
Question 671: Which of the following statements about paramyxoviruses is false?
- A. Belong to the family Paramyxoviridae
- B. Are DNA viruses (Correct Answer)
- C. Are RNA viruses
- D. Have linear nucleic acid
Explanation: ***Are DNA viruses*** - Paramyxoviruses are characterized by their **single-stranded, negative-sense RNA genome**, not DNA. - Their replication and transcription processes occur in the cytoplasm, which is typical for RNA viruses. *Belong to the family Paramyxoviridae* - This statement is correct; paramyxoviruses are indeed classified under the **family Paramyxoviridae**. - This family includes important human pathogens like measles, mumps, and respiratory syncytial virus (RSV). *Have linear nucleic acid* - This statement is correct as paramyxoviruses possess a **linear, non-segmented RNA genome**. - The linear nature differentiates them from viruses with segmented genomes, such as influenza viruses. *Are RNA viruses* - This statement is correct; paramyxoviruses are characterized by their **RNA genome**. - Specifically, they are **negative-sense, single-stranded RNA viruses**.
Pathology
1 questionsWhat is the key pathophysiological difference between acid and alkali injuries in terms of tissue necrosis?
NEET-PG 2015 - Pathology NEET-PG Practice Questions and MCQs
Question 671: What is the key pathophysiological difference between acid and alkali injuries in terms of tissue necrosis?
- A. Acid injuries cause coagulative necrosis
- B. Alkali injuries lead to deeper tissue damage
- C. Acid injuries are less severe than alkali injuries
- D. Alkali injuries cause liquefactive necrosis (Correct Answer)
Explanation: ***Alkali injuries cause liquefactive necrosis*** - **Alkali burns** result in **liquefaction necrosis**, which involves the dissolution of tissue and cells, leading to a much deeper and progressive injury as the alkali penetrates further into tissues. - This is the **key pathophysiological difference** that distinguishes alkali from acid injuries - the TYPE of necrosis (liquefactive vs coagulative). - This type of necrosis allows the alkali to continue damaging underlying tissues and can lead to more extensive and severe scarring and complications. *Acid injuries cause coagulative necrosis* - While this statement is **medically true**, it only describes what acids do without explicitly stating the **difference** or comparison with alkali injuries. - The question asks for the KEY **difference**, and this option presents only one half of the comparison. - **Acid burns** typically cause **coagulation necrosis**, forming a coagulum or eschar that precipitates proteins and creates a barrier, thereby limiting the depth of penetration. - The correct answer (alkali → liquefactive necrosis) better captures the distinguishing pathophysiological feature. *Alkali injuries lead to deeper tissue damage* - This statement is true but serves as a **consequence** of the underlying **liquefactive necrosis** rather than the primary pathophysiological mechanism itself. - The liquefaction process continuously destroys cells and extracellular matrix, enabling the caustic agent to propagate deeply into the tissue. - This describes the OUTCOME rather than the KEY pathophysiological mechanism. *Acid injuries are less severe than alkali injuries* - This is a **generalization about severity** rather than identifying the specific pathophysiological mechanism of tissue death. - While generally true due to the **coagulation necrosis** limiting the depth of penetration of acids, severity can vary based on concentration, duration of exposure, and other factors. - The formation of a protective eschar in acid burns often prevents further significant tissue destruction, unlike the progressive damage seen in alkali burns.
Pharmacology
5 questionsBest method of treatment for methyl alcohol poisoning is:
Which statement is true regarding the influenza vaccine?
In the context of pharmacology, what is the term 'Mickey Finn' commonly associated with?
Which of the following substances is commonly known as an arrow poison used by indigenous South American tribes?
From which part of the Papaver somniferum plant does the latex, commonly referred to as 'milk', exude?
NEET-PG 2015 - Pharmacology NEET-PG Practice Questions and MCQs
Question 671: Best method of treatment for methyl alcohol poisoning is:
- A. Calcium gluconate
- B. Ethyl alcohol (Correct Answer)
- C. Amphetamines
- D. 1% Ammonia
Explanation: ***Ethyl alcohol*** - **Ethanol** (ethyl alcohol) acts as a competitive substrate for **alcohol dehydrogenase**, the enzyme responsible for metabolizing **methanol** into toxic metabolites like formaldehyde and formic acid. - By saturating alcohol dehydrogenase, ethanol prevents the formation of these toxic metabolites, allowing methanol to be excreted unchanged. - **Clinical note**: While **fomepizole** (4-methylpyrazole) is now the preferred first-line antidote when available, **ethanol** remains an effective and widely used alternative, especially in resource-limited settings. - **Administration**: IV ethanol is given to maintain blood ethanol concentration of 100-150 mg/dL. *Calcium gluconate* - **Calcium gluconate** is primarily used to treat **hypocalcemia**, ethylene glycol poisoning (for hypocalcemia), or hydrofluoric acid burns. - It has no role in the management of methyl alcohol poisoning as it does not interfere with the metabolism of methanol or its toxic byproducts. *Amphetamines* - **Amphetamines** are central nervous system stimulants used for conditions like ADHD and narcolepsy. - They have no therapeutic benefit or antidotal properties in the context of methanol poisoning. *1% Ammonia* - **Ammonia** is a strong base and is highly corrosive; it has no medical application as an antidote for methanol poisoning. - Administering ammonia would cause direct tissue damage and exacerbate patient harm due to its toxic and caustic properties.
Question 672: Which statement is true regarding the influenza vaccine?
- A. The live attenuated vaccine is given by nasal spray.
- B. All statements are correct. (Correct Answer)
- C. The inactivated vaccine is used most commonly.
- D. The inactivated vaccine is given intramuscularly in the deltoid.
Explanation: ***All statements are correct.*** - Each of the preceding statements is factually accurate regarding influenza vaccines. - The **inactivated vaccine** is widely used, the **live attenuated vaccine** is administered via nasal spray, and the **inactivated vaccine** is given intramuscularly [1]. *The inactivated vaccine is used most commonly.* - The **inactivated influenza vaccine (IIV)**, given by injection, is the most frequently administered type of influenza vaccine. - It is recommended for most age groups and is safe for individuals with chronic medical conditions, pregnant women, and the elderly. *The live attenuated vaccine is given by nasal spray.* - The **live attenuated influenza vaccine (LAIV)**, also known as FluMist, is administered as a **nasal spray** [1]. - This vaccine is suitable for healthy individuals aged 2-49 years and is not recommended for pregnant women or individuals with certain immune compromising conditions. *The inactivated vaccine is given intramuscularly in the deltoid.* - The standard route of administration for the **inactivated influenza vaccine (IIV)** is via **intramuscular injection**, most commonly into the **deltoid muscle** in adults and older children [1]. - This method ensures proper absorption and an effective immune response, a common practice for many vaccines.
Question 673: In the context of pharmacology, what is the term 'Mickey Finn' commonly associated with?
- A. Chloroform
- B. Methyl alcohol
- C. Chloral hydrate (Correct Answer)
- D. Ethylene glycol
Explanation: ***Chloral hydrate*** - A "Mickey Finn" is a slang term for a drink **laced with a psychoactive drug or incapacitating agent** given to an unsuspecting person. - Historically, **chloral hydrate** was a common substance used for this purpose due to its rapid sedative-hypnotic effects. *Chloroform* - While chloroform is a potent anesthetic and sedative, it is primarily used as an **inhalant** and is not typically administered orally in drinks. - Ingesting chloroform in large quantities can be **fatal due to severe hepatotoxicity and neurotoxicity**. *Methyl alcohol* - **Methyl alcohol (methanol)** is highly toxic and causes severe metabolic acidosis, blindness, and death, even in small amounts. - It does not induce the quick, incapacitating sedative effects associated with a "Mickey Finn" but rather a **delayed, severe poisoning syndrome**. *Ethylene glycol* - **Ethylene glycol** is an antifreeze agent that is also highly toxic, causing kidney failure and metabolic derangements. - Similar to methanol, its effects are **delayed and severe**, not the immediate incapacitating sedation implied by the term "Mickey Finn."
Question 674: Which of the following substances is commonly known as an arrow poison used by indigenous South American tribes?
- A. Opium
- B. Curare (Correct Answer)
- C. Cannabis
- D. Cyanide
Explanation: ***Curare*** - **Curare** is the traditional name for South American arrow poisons derived from plants, primarily *Chondrodendron tomentosum* and *Strychnos* species - It acts as a **competitive non-depolarizing neuromuscular blocking agent**, blocking nicotinic receptors at the neuromuscular junction - Causes **skeletal muscle paralysis** by competing with acetylcholine, leading to respiratory failure in prey - **Clinical relevance:** Tubocurarine (d-tubocurarine), derived from curare, was historically used as a muscle relaxant in surgery; modern derivatives include atracurium, vecuronium, and rocuronium *Opium* - **Opium** is derived from *Papaver somniferum* (opium poppy) and contains alkaloids like morphine and codeine - Acts on **opioid receptors** in the CNS to produce analgesia and sedation - Not used as an arrow poison by South American tribes; its effects are analgesic rather than paralytic *Cannabis* - **Cannabis** (*Cannabis sativa*) contains psychoactive compounds like THC (tetrahydrocannabinol) - Acts on **cannabinoid receptors** producing psychoactive and analgesic effects - Not used as an arrow poison; lacks the rapid paralytic action needed for hunting *Cyanide* - **Cyanide** inhibits cytochrome c oxidase, blocking cellular respiration and causing rapid cell death - While highly toxic, it is **not the traditional arrow poison** of South American indigenous tribes - Traditional arrow poisons like curare cause neuromuscular paralysis rather than cellular asphyxiation
Question 675: From which part of the Papaver somniferum plant does the latex, commonly referred to as 'milk', exude?
- A. Leaf of the plant
- B. Root of the plant
- C. Seeds of the plant
- D. Unripe capsule of the plant (Correct Answer)
Explanation: ***Unripe capsule of the plant*** - The **latex** (or 'milk') containing **opioid alkaloids** like morphine and codeine is primarily harvested by incising the **unripe seed capsules** of the *Papaver somniferum* plant. - This milky sap is then collected and dried to produce **crude opium**. *Leaf of the plant* - The leaves of *Papaver somniferum* do not contain significant amounts of the latex and are not the primary source of **opium alkaloids**. - While some **alkaloids** might be present in trace amounts, they are not extracted commercially from the leaves. *Root of the plant* - The roots of the poppy plant are not known to exude latex or to be a significant source of medically relevant **opioid alkaloids**. - Their primary function is absorption of water and nutrients, and anchoring the plant. *Seeds of the plant* - While the dried seeds are used for culinary purposes (poppy seeds), they contain very low levels of **opioid alkaloids** compared to the latex. - The latex is produced within the **capsule** before the seeds fully mature.