NEET-PG 2015 Practice Questions

Q: What is the narrowest part of the nasal cavity?

Internal nasal valve area. ***Internal nasal valve area*** - The **internal nasal valve** (ostium internum) is the **narrowest part of the nasal cavity**, located approximately 1.3 cm from the nostril - Formed by the **septal cartilage medially**, **upper lateral cartilage laterally**, **nasal floor inferiorly**, and **anterior head of inferior turbinate posteriorly** - The angle between the septum and upper lateral cartilage is typically **10-15 degrees**, creating the narrowest cross-sectional area - Accounts for approximately **50% of total nasal airway resistance** and is clinically the most critical site for airflow regulation - **Clinical significance**: Site of nasal valve collapse in breathing disorders *Vestibule* - The **nasal vestibule** is the most anterior part of the nasal cavity lined with **keratinized stratified squamous epithelium** and **vibrissae** (nasal hairs) - While it is a narrow region, it is **NOT the narrowest part** of the nasal cavity - Acts as the entrance to the nasal cavity but has a larger cross-sectional area than the internal nasal valve *Choanae* - The **choanae** are the **posterior openings** of the nasal cavity that open into the nasopharynx - They represent a transition point for airflow but are relatively **wide openings**, not the narrowest part *Inferior turbinate* - The **inferior turbinate** is a bony projection covered with erectile tissue that increases surface area for warming and humidifying air - While it can become engorged and narrow the airway pathologically, anatomically it does not constitute the narrowest fixed point of the nasal passage

Q: Which category waste is disposed in red bags?

Contaminated recyclable waste (Category 3). ***Contaminated recyclable waste (Category 3)*** - **Red bags** are specifically designated for the disposal of **contaminated recyclable waste**, which includes items like tubing, catheters, intravenous sets, and soiled plastic bottles. - This waste is often contaminated with blood or body fluids but can be sterilized and recycled after proper treatment. *Human anatomical waste (Category 1)* - **Human anatomical waste**, such as tissues, organs, body parts, and fetuses, is typically disposed of in **yellow bags**. - This category usually requires incineration or deep burial due to its biological hazard. *Glassware and metallic implants (Category 2)* - **Glassware** (e.g., broken glass, used vials) and **metallic implants** (e.g., orthopedic implants) are typically disposed of in puncture-proof containers, often **blue** or transparent bins, for safe handling and potential recycling. - These items are separated to prevent injuries and facilitate specific recycling or treatment methods. *Pharmaceutical waste (Category 4)* - **Pharmaceutical waste** includes discarded medicines, expired drugs, and cytotoxic drugs, and it is usually collected in **yellow bags** or designated labeled containers. - Its disposal requires specific chemical treatment, incineration, or secure landfilling to prevent environmental contamination.

Q: Hepatic Encephalopathy is predisposed by all, Except:

Hyperkalemia. ***Hyperkalemia*** - **Hyperkalemia** is not a known trigger for hepatic encephalopathy; in fact, **hypokalemia** is a more common electrolyte disturbance that can precipitate it due to its effect on renal ammonia excretion. - Electrolyte imbalances that contribute to hepatic encephalopathy usually involve **hypokalemia**, **hyponatremia**, or **alkalosis**, which affect **ammonia metabolism** and neuronal excitability [1]. *Dehydration* - **Dehydration** can lead to **reduced renal perfusion**, impairing the kidneys' ability to clear **ammonia** and other toxins, thus increasing their concentration in the blood. - It also contributes to **hemoconcentration**, elevating blood **ammonia levels** and increasing the risk of hepatic encephalopathy [1]. *Constipation* - **Constipation** allows for a longer transit time of stool in the colon, providing more opportunity for **intestinal bacteria** to produce **ammonia** from protein breakdown [1]. - The increased production and absorption of ammonia from the gut contribute significantly to the **nitrogenous load** in the bloodstream, predisposing to hepatic encephalopathy [1]. *GI Bleeding* - **Gastrointestinal bleeding** (GI bleeding) introduces a large protein load (blood) into the GI tract, which is then broken down by bacterial action. - This breakdown generates a significant amount of **ammonia** and other nitrogenous compounds, which are then absorbed into the bloodstream, overwhelming the impaired liver's ability to detoxify them and precipitating hepatic encephalopathy [1].

Q: Which of the following statements about Corynebacterium diphtheriae is true?

Toxin production is dependent on iron concentration. ***Toxin production is dependent on iron concentration*** - The production of **diphtheria toxin** by *Corynebacterium diphtheriae* is directly regulated by the iron concentration in the environment. - When **iron levels are low**, the diphtheria toxin repressor (DTxR) is inactivated, leading to increased toxin production. *All strains produce toxin* - Not all strains of *Corynebacterium diphtheriae* produce the diphtheria toxin; only those strains that are **lysogenized by a bacteriophage carrying the tox gene** are toxigenic. - Non-toxigenic strains can cause other infections but do not produce the classic diphtheria disease. *The toxin is heat stable* - The **diphtheria toxin** is a **heat-labile** protein, meaning its activity can be destroyed by heat. - Heating diphtheria toxin to 60°C for 30 minutes can inactivate its pathogenic effects. *It inhibits cAMP* - The diphtheria toxin does not inhibit **cAMP**; instead, it acts by **ADP-ribosylating and inactivating elongation factor-2 (EF-2)**, thereby inhibiting protein synthesis in eukaryotic cells. - Inhibition of EF-2 ultimately leads to cell death.

Q: Which of the following statements about Legionella is most accurate?

Aerosol inhalation is a common mode of transmission.. ***Aerosol inhalation is a common mode of transmission.*** - **Legionella pneumophila** is primarily transmitted through **inhalation of aerosolized water droplets** containing the bacteria - Common sources include **cooling towers, air conditioning systems, hot tubs, showerheads**, and decorative fountains - This is the **most defining and clinically important characteristic** of Legionella transmission - Understanding aerosol transmission is crucial for **outbreak control and prevention strategies** *There is no human-to-human transmission.* - This statement is **medically accurate** - Legionella does NOT spread from person to person - However, this is a secondary characteristic compared to the primary transmission mode - The question asks for the **most accurate** statement, making aerosol transmission more definitive *Prolonged carriers are common.* - This is **INCORRECT** - Legionella does NOT cause a chronic carrier state in humans - The bacteria **colonizes environmental water systems and amoebae** (like *Acanthamoeba* and *Naegleria*), not human hosts - Humans are accidental hosts through aerosol exposure *All of the options are true* - This is **INCORRECT** because "Prolonged carriers are common" is false - Only two of the three substantive statements are true

Q: Which immunoglobulin does Protein A of Staphylococcus aureus bind to?

IgG. ***IgG*** - **Protein A** of *Staphylococcus aureus* binds to the **Fc region** of IgG antibodies. - This binding mechanism helps *S. aureus* in **evading opsonization** and phagocytosis by interfering with the host immune response. *IgA* - IgA is primarily found in **mucosal secretions** and its primary role is in mucosal immunity. - Protein A does not preferentially bind to IgA; instead, some bacteria produce specific **IgA proteases** to cleave and inactivate IgA. *IgD* - IgD is found mostly on the surface of **B lymphocytes** and its main role is in B cell activation. - Protein A does not have a significant binding affinity for IgD. *IgE* - IgE is involved in **allergic reactions** and defense against parasites. - Protein A does not bind to IgE; binding to IgE is typically mediated by specific IgE receptors on mast cells and basophils.

Q: Proteus isolated from a patient of UTI will show which biochemical reaction.

Production of phenylpyruvic acid from phenylalanine. ***Production of phenylpyruvic acid from phenylalanine*** - *Proteus* species possess the enzyme **phenylalanine deaminase**, which deaminates phenylalanine to **phenylpyruvic acid**. - This reaction is a **key biochemical test** used to identify *Proteus*, *Providencia*, and *Morganella* species. *Hydrolysis of esculin in bile* - This reaction is characteristic of **Group D streptococci** and **enterococci**, not *Proteus* species. - The organism hydrolyzes **esculin** in the presence of bile, turning the agar black. *Sensitivity to colchicine* - **Colchicine** is an anti-inflammatory drug, not part of standard **biochemical identification tests** for bacteria. - This is not a recognized biochemical reaction used to identify *Proteus* or any bacterial species. *Sensitivity to bacitracin* - **Bacitracin sensitivity** is primarily used to differentiate **Group A streptococci** (e.g., *Streptococcus pyogenes*) from other beta-hemolytic streptococci. - It is an **antibiotic susceptibility test**, not a biochemical reaction characteristic of *Proteus* species.

Q: Where is the intraocular lens placed during cataract surgery?

Capsular bag. ***Capsular bag*** - The **capsular bag** is the natural anatomical space where the human crystalline lens resides and is the ideal location for an intraocular lens (IOL) to mimic the natural lens's position and function. - Placing the IOL in the capsular bag provides **optimal stability**, centration, and reduces the risk of complications such as glare or secondary glaucoma. *Surface of iris* - Placing an IOL on the surface of the iris (**iris-fixated IOL**) is a less common surgical approach, typically reserved for cases where capsular support is absent or insufficient. - This position can lead to potential complications including **iris chafing**, pigment dispersion, and increased risk of uveitis or secondary glaucoma. *Over the face of vitreous* - Placing an IOL over the face of the vitreous typically occurs in cases of **capsular rupture** with inadequate posterior capsule support, requiring anterior vitrectomy and alternative IOL fixation. - This position is less stable and carries a higher risk of **vitreous prolapse**, retinal detachment, and cystoid macular edema compared to capsular bag placement. *Around the limbus* - The limbus is the **junction between the cornea and sclera** and is an entirely incorrect location for an intraocular lens implant. - An IOL around the limbus would be outside the globe and would serve no optical purpose within the eye, leading to **severe visual impairment** and potentially structural damage.

Q: Kayser-Fleischer ring is found in which layer of cornea?

Descemet's membrane. ***Descemet's membrane*** - Kayser-Fleischer rings are caused by **copper deposition** at the periphery of the cornea, specifically within **Descemet's membrane**. - This membrane is located between the **corneal stroma** and the **endothelium**. *Bowman's layer* - Bowman's layer is a thin, acellular layer of the cornea that lies beneath the **corneal epithelium**. - While it plays a role in corneal integrity, it is not the site of **copper deposition** in Wilson's disease. *Corneal stroma* - The corneal stroma is the thickest layer of the cornea, composed primarily of **collagen fibrils**. - Although it contains most of the corneal mass, **copper deposition** in Kayser-Fleischer rings does not specifically occur within the main stromal layer. *Endothelium* - The corneal endothelium is the innermost layer of the cornea, responsible for maintaining **corneal deturgescence**. - While it is adjacent to Descemet's membrane, the copper rings are deposited in the membrane itself, not directly in the endothelial cell layer.

Q: The main muscle affected in congenital muscular torticollis is?

Sternocleidomastoid. ***Sternocleidomastoid*** - Congenital muscular torticollis (CMT) is primarily caused by **unilateral fibrosis and shortening of the sternocleidomastoid muscle (SCM)**. - This leads to the characteristic **head tilt towards the affected side** and **chin rotation to the opposite side**. *Trapezius* - The trapezius muscle is primarily involved in **shrugging the shoulders**, extending and rotating the head and neck, but is not the main muscle affected in CMT. - While it can become secondarily tight in response to persistent head positioning, it is **not the primary pathological muscle** in CMT. *Scalenus Anticus* - The scalenus anticus (anterior scalene muscle) is involved in **neck flexion and elevation of the first rib** during forced inspiration. - It plays a role in various neck pain syndromes and brachial plexus compression, but it is **not the defining muscle in congenital muscular torticollis**. *Omohyoid* - The omohyoid is a **strap muscle of the neck** that depresses the hyoid bone. - It has no primary involvement in the **pathophysiology or clinical presentation of congenital muscular torticollis**.

Question 1

What is the narrowest part of the nasal cavity?

Accepted Answer

Internal nasal valve area

Answer

Vestibule

Answer

Choanae

Answer

Inferior turbinate

Question 2

Which category waste is disposed in red bags?

Accepted Answer

Contaminated recyclable waste (Category 3)

Answer

Glassware and metallic implants (Category 2)

Answer

Human anatomical waste (Category 1)

Answer

Pharmaceutical waste (Category 4)

Question 3

Hepatic Encephalopathy is predisposed by all, Except:

Accepted Answer

Hyperkalemia

Answer

Constipation

Answer

GI Bleeding

Answer

Dehydration

Question 4

Which of the following statements about Corynebacterium diphtheriae is true?

Accepted Answer

Toxin production is dependent on iron concentration

Answer

All strains produce toxin

Answer

The toxin is heat stable

Answer

It inhibits cAMP

Question 5

Which of the following statements about Legionella is most accurate?

Accepted Answer

Aerosol inhalation is a common mode of transmission.

Answer

Prolonged carriers are common.

Answer

There is no human-to-human transmission.

Answer

All of the options are true

Question 6

Which immunoglobulin does Protein A of Staphylococcus aureus bind to?

Accepted Answer

IgG

Answer

IgA

Answer

IgD

Answer

IgE

Question 7

Proteus isolated from a patient of UTI will show which biochemical reaction.

Accepted Answer

Production of phenylpyruvic acid from phenylalanine

Answer

Hydrolysis of esculin in bile

Answer

Sensitivity to colchicine

Answer

Sensitivity to bacitracin

Question 8

Where is the intraocular lens placed during cataract surgery?

Accepted Answer

Capsular bag

Answer

Surface of iris

Answer

Around the limbus

Answer

Over the face of vitreous

Question 9

Kayser-Fleischer ring is found in which layer of cornea?

Accepted Answer

Descemet's membrane

Answer

Endothelium

Answer

Bowman's layer

Answer

Corneal stroma

Question 10

The main muscle affected in congenital muscular torticollis is?

Accepted Answer

Sternocleidomastoid

Answer

Trapezius

Answer

Scalenus Anticus

Answer

Omohyoid

NEET-PG 2015

Anatomy

Community Medicine

Internal Medicine

Microbiology

Ophthalmology

Orthopaedics