NEET-PG 2012 Practice Questions

Q: What substance is measured in the vitreous humor to estimate the time since death?

Potassium. ***Potassium*** - **Potassium** concentration in the vitreous humor increases predictably after death due to the breakdown of cellular membranes and passive diffusion from cells. - This consistent post-mortem rise makes it a reliable marker for estimating the **post-mortem interval** (PMI) or time since death. *Sodium* - While sodium is present in the vitreous humor, its post-mortem changes are not as consistent or predictable as potassium for estimating the **time since death**. - Sodium levels tend to decrease slightly after death, but this decline is influenced by various factors and is less reliable for **PMI determination**. *Proteins* - **Proteins** are generally stable in the vitreous humor for some time post-mortem, but their levels do not show a consistent or predictable change that can be used to accurately estimate the **time since death**. - Measuring protein levels is more useful in assessing specific eye pathologies rather than **PMI**. *Chloride* - **Chloride** concentrations in the vitreous humor exhibit post-mortem changes, but like sodium, they are not as precise or reliable as potassium for estimating the **post-mortem interval**. - Its diffusion out of the vitreous humor can be more variable and less consistently linear than potassium's influx.

Q: In a case of hanging, the ligature marks on the neck are an example of which type of injury?

Printed abrasion. ***Printed abrasion*** - Ligature marks in hanging specifically refer to a type of **abrasion** where the pattern or texture of the ligature (rope, cord, etc.) is imprinted onto the skin. - This occurs due to the **pressure and friction** of the ligature against the epidermis, causing superficial scraping and leaving a distinct pattern. *Contusion* - A **contusion**, or bruise, results from bleeding into the tissues as a consequence of blunt trauma, causing discoloration of the skin. - While some mild bruising might coexist with ligature marks, the primary and distinctive injury from a ligature is an abrasion of the skin surface, not solely bleeding underneath. *Laceration* - A **laceration** is a tear or cut in the skin and underlying tissues typically caused by the forceful impact of a blunt object or shear forces. - Ligature marks from hanging are generally superficial skin injuries and do not involve deep tearing of tissues typical of a laceration. *Bruise* - A **bruise** is another term for a contusion, involving hemorrhage into the tissues without breaking the skin. - While bleeding may occur under the ligature mark, the defining characteristic of the mark itself is the superficial scraping or impression on the skin surface, which is an abrasion, not primarily a bruise.

Q: Widmark's formula helps in the measurements of blood level of:

Alcohol. ***Alcohol*** - **Widmark's formula** is a widely used method to estimate an individual's **blood alcohol concentration (BAC)** based on the amount of alcohol consumed, body weight, and gender. - This formula helps in forensic toxicology and clinical settings to assess the level of **intoxication**. *Barbiturate drugs* - The levels of **barbiturate drugs** are typically measured using techniques like **gas chromatography-mass spectrometry (GC-MS)** or **high-performance liquid chromatography (HPLC)**. - While various formulas might exist for pharmacokinetic modeling of specific drugs, Widmark's formula is not applicable to barbiturates. *Cocaine derivatives* - **Cocaine and its metabolites** (e.g., benzoylecgonine) are detected and quantified in biological samples (blood, urine) using analytical methods such as **immunoassay**, **GC-MS**, or **LC-MS/MS**. - Widmark's formula is specific to alcohol metabolism and distribution, not cocaine. *Benzodiazepine medications* - The measurement of **benzodiazepine concentrations** in blood is predominantly done using **chromatographic methods** (e.g., GC-MS, LC-MS/MS) due to their complex metabolism and structural diversity. - Widmark's formula is not designed to calculate levels of benzodiazepines.

Q: Which of the following is NOT considered a grievous injury?

Breast contusion. ***Breast contusion*** - A breast contusion, while painful, is generally a **minor injury** that typically resolves without long-term significant functional impairment or disfigurement. - It does not meet the criteria for a grievous injury under **IPC Section 320**, which requires severe, lasting physical harm or functional loss. *Multiple facial scars* - Multiple facial scars can lead to significant and **permanent disfigurement of the face**, which is explicitly listed as a grievous injury under IPC Section 320. - Such scarring can have profound psychological impacts and may require extensive reconstructive surgery. *Femur fracture* - A femur fracture is a **grievous injury** under IPC Section 320 as it constitutes a **"fracture or dislocation of a bone."** - Additionally, it results in **severe pain**, prolonged disability, and often requires extensive medical intervention including surgery, with potential for protracted loss of use of a limb. *Emasculation injury* - Emasculation refers to the **removal or destruction of male reproductive organs**, which is explicitly listed as a grievous injury under IPC Section 320. - This type of injury results in **permanent impairment of reproductive powers** and qualifies as privation of a member or joint.

Q: In nutrient agar the concentration of agar is

1.5%. ***1.5%*** - A concentration of **1.5% agar** is the standard amount used in **nutrient agar** to provide a solid medium for bacterial growth. - This concentration allows for proper solidification, forming a stable gel suitable for culturing microorganisms. *1%* - A 1% agar concentration would likely result in a **softer, less firm medium**, which might not be ideal for handling or for supporting the colonies of some microorganisms. - This concentration is sometimes used for specific purposes, such as preparing **semi-solid agars** for motility studies, but not for general solid media. *3%* - A 3% agar concentration would create a **much firmer, more rigid gel**, which could potentially hinder the diffusion of nutrients to bacterial colonies or make microbial inoculation more difficult. - Such high concentrations are less commonly used for routine bacterial culture and are reserved for specific applications requiring a very stiff medium. *4%* - A 4% agar concentration would produce an **extremely firm and brittle gel**, making it very hard to work with and potentially impeding bacterial growth due to poor nutrient diffusion. - This concentration is significantly higher than what is typically required for standard solid culture media.

Q: Which of the following statements about Chlamydia is false?

Gram positive. ***Gram positive*** - Chlamydia are **Gram-negative** bacteria, despite their unique cell wall structure which lacks a peptidoglycan layer but contains an outer membrane with lipopolysaccharide (LPS) [1]. - The statement that Chlamydia are Gram positive is therefore **FALSE**, making this the correct answer. *Obligate intracellular organism* - This statement is TRUE. Chlamydia are indeed **obligate intracellular organisms**, meaning they can only replicate inside host cells [2]. - They rely on the host cell for ATP and other metabolic precursors, earning them the nickname "energy parasites" [2]. *Reticulate body is metabolically active* - This statement is TRUE. The **reticulate body (RB)** is the metabolically active and replicative form of Chlamydia that resides within the host cell [1]. - It undergoes binary fission to produce more RBs before differentiating back into elementary bodies [1]. *Replicate by binary fission* - This statement is TRUE. The **reticulate bodies** of Chlamydia replicate primarily through **binary fission** within the inclusion bodies inside the host cell cytoplasm [1]. - This process allows for the rapid amplification of the bacteria.

Q: Which atypical mycobacteria are known for pigment production?

M. gordonae, M. szulgai. **Correct: M. gordonae, M. szulgai** - **M. gordonae** is a classic **scotochromogen**, producing yellow-orange pigment in both light and dark conditions - **M. szulgai** is unique as it shows **dual chromogenicity**: photochromogen at 25°C and scotochromogen at 37°C - These are the classic examples of **pigment-producing atypical mycobacteria** used for classification purposes - Pigment production (Runyon classification) is a key characteristic differentiating atypical mycobacteria from *M. tuberculosis* *Incorrect: M. fortuitum, M. chelonae* - These are **rapid growers** (Runyon Group IV) and are typically **non-chromogens** - Not primarily known or highlighted for pigment production as a defining feature - Clinically important for causing **skin and soft tissue infections**, especially in post-traumatic or post-surgical settings *Incorrect: M. xenopi, Mycobacterium avium complex (MAC)* - **M. xenopi** is a **non-chromogen** (no pigment production) and is thermophilic - **MAC** (*M. avium* and *M. intracellulare*) are also **non-chromogens** - MAC is an important cause of disseminated disease in immunocompromised patients (especially AIDS) and pulmonary disease in patients with pre-existing lung disease *Incorrect: M. ulcerans (non-pigment producing)* - Correctly identified as a **non-chromogen** (no pigment production) - Causes **Buruli ulcer**, a severe necrotizing skin disease - Distinguished by production of **mycolactone toxin**, not pigment characteristics

Q: Which of the following statements about B. quintana is false?

Tick is the vector. ***Tick is the vector*** - This statement is **false** because *Bartonella quintana* (B. quintana) is primarily transmitted by the **human body louse**, not ticks. - The disease it causes, **trench fever**, was historically associated with crowded and unsanitary conditions where lice thrive. *Causes trench fever* - *B. quintana* is the causative agent of **trench fever**, a louse-borne illness characterized by recurrent febrile episodes. - This symptom was highly prevalent among soldiers in the trenches during World War I. *Recurrence is common* - **Relapsing fever** (recurrence) is a characteristic feature of trench fever, often occurring several times over weeks or months. - This recurrence is due to the **intracellular survival of *Bartonella* species** within erythrocytes and endothelial cells, making clearance difficult. *Not detected by Weil-Felix reaction* - The **Weil-Felix reaction** is a serological test used to detect certain rickettsial infections, which cross-react with *Proteus* antigens. - *Bartonella quintana* infections **do not typically produce antibodies** that cross-react with *Proteus* antigens; therefore, the Weil-Felix test would not be positive for trench fever.

Q: Which organism can be isolated from stool & sputum?

Paragonimus. ***Paragonimus*** - *Paragonimus* species, particularly *P. westermani* (the **lung fluke**), are known to infest the lungs, leading to symptoms like **cough** and **sputum production**, where their eggs can be found. - While residing in the lungs, eggs can be swallowed, passed through the gastrointestinal tract, and subsequently found in **stool samples**. *Fasciola* - *Fasciola hepatica* (the **sheep liver fluke**) primarily infects the **liver and biliary ducts**. - Its eggs are typically found in **stool samples** but not in sputum, as it does not infest the respiratory tract. *Clonorchis* - *Clonorchis sinensis* (the **Chinese liver fluke**) also primarily inhabits the **bile ducts** of the liver. - Similar to *Fasciola*, its eggs are excreted in **feces** and are not found in sputum. *P. carinii* - *Pneumocystis jirovecii* (formerly *Pneumocystis carinii*) is a **fungus** that causes **pneumonia** (PCP) in immunocompromised individuals. - It is exclusively found in the **lungs** and identified in respiratory specimens like sputum or bronchoalveolar lavage, not in stool.

Q: Which of the following antiepileptic drugs is most classically associated with causing hirsutism?

Phenytoin. ***Phenytoin*** - **Phenytoin** is the **most classically associated** antiepileptic drug with **hirsutism**, which is abnormal/excessive growth of hair [1]. - The mechanism involves changes in **androgen metabolism** and stimulation of hair follicle growth. - Other cosmetic side effects include **gingival hyperplasia** and **coarsening of facial features** [1].*Valproate* - Valproate can paradoxically cause both **hair loss (alopecia)** and **hirsutism**, particularly in women and children. - However, phenytoin has a **stronger and more classical association** with hirsutism. - Valproate is also known for **weight gain**, **hepatotoxicity**, **pancreatitis**, and **teratogenicity**.*Carbamazepine* - Carbamazepine's common side effects include **drowsiness**, **dizziness**, **diplopia**, and **hyponatremia**. - It is not classically linked to **hirsutism** as a prominent adverse effect. - Can cause **agranulocytosis** and **Stevens-Johnson syndrome** in rare cases.*Phenobarbitone* - Phenobarbitone is an older antiepileptic drug associated with **sedation**, **cognitive impairment**, and **dependence**. - It does not commonly cause **hirsutism**. - Also causes **enzyme induction** leading to multiple drug interactions.

Question 1

What substance is measured in the vitreous humor to estimate the time since death?

Accepted Answer

Potassium

Answer

Sodium

Answer

Proteins

Answer

Chloride

Question 2

In a case of hanging, the ligature marks on the neck are an example of which type of injury?

Accepted Answer

Printed abrasion

Answer

Laceration

Answer

Bruise

Answer

Contusion

Question 3

Widmark's formula helps in the measurements of blood level of:

Accepted Answer

Alcohol

Answer

Barbiturate drugs

Answer

Cocaine derivatives

Answer

Benzodiazepine medications

Question 4

Which of the following is NOT considered a grievous injury?

Accepted Answer

Breast contusion

Answer

Multiple facial scars

Answer

Femur fracture

Answer

Emasculation injury

Question 5

In nutrient agar the concentration of agar is

Accepted Answer

1.5%

Answer

1%

Answer

3%

Answer

4%

Question 6

Which of the following statements about Chlamydia is false?

Accepted Answer

Gram positive

Answer

Reticulate body is metabolically active

Answer

Replicate by binary fission

Answer

Obligate intracellular organism

Question 7

Which atypical mycobacteria are known for pigment production?

Accepted Answer

M. gordonae, M. szulgai

Answer

M. fortuitum, M. chelonae

Answer

M. xenopi, Mycobacterium avium complex (MAC)

Answer

M. ulcerans (non-pigment producing)

Question 8

Which of the following statements about B. quintana is false?

Accepted Answer

Tick is the vector

Answer

Recurrence is common

Answer

Causes trench fever

Answer

Not detected by Weil-Felix reaction

Question 9

Which organism can be isolated from stool & sputum?

Accepted Answer

Paragonimus

Answer

Fasciola

Answer

P. carinii

Answer

Clonorchis

Question 10

Which of the following antiepileptic drugs is most classically associated with causing hirsutism?

Accepted Answer

Phenytoin

Answer

Valproate

Answer

Carbamazepine

Answer

Phenobarbitone

NEET-PG 2012

Forensic Medicine

Microbiology

Pharmacology