FMGE 2023 Practice Questions

Q: Identify the sinus marked in the image.

Maxillary sinus. ***Maxillary sinus*** - The image correctly identifies the **maxillary sinuses**, which are the largest paranasal sinuses located within the body of the maxilla, lateral to the nasal cavity and inferior to the orbits. - These sinuses are often implicated in **sinusitis**, and pain from an infection can be referred to the maxillary (upper) teeth. *Frontal sinus* - The **frontal sinuses** are located superior to the orbits, within the frontal bone of the forehead. In the diagram, these are represented by the purple structures above the eyes. - They are not situated in the cheek area as highlighted by the red circle. *Pyriform sinus* - The **pyriform sinus** (or fossa) is not a paranasal sinus but a recess on either side of the laryngopharynx, involved in swallowing. - It is located in the throat, much inferior to the structures shown in the facial diagram. *Ethmoid sinus* - The **ethmoid sinuses** are a collection of small air cells located between the orbits, within the ethmoid bone. In the diagram, they are the light blue structures superior to the maxillary sinuses. - They are situated medial to the orbits and superior to the highlighted maxillary sinuses.

Q: Which of the following immunoglobulins shows the highest concentration in serum?

IgG. ***IgG*** - **IgG** accounts for approximately **75-80%** of the total immunoglobulins in human serum, making it the highest in concentration.- Its high levels reflect its crucial roles in providing **long-term humoral immunity**, neutralizing toxins, and being the only class able to cross the **placenta** to confer passive immunity to the fetus.*IgM* - **IgM** is present at much lower concentrations (about 5-10%); it is primarily known for being the first antibody produced during a **primary immune response**. - Although it is the largest immunoglobulin (a pentamer) and effective at complement activation, its total serum concentration is substantially less than IgG.*IgA* - **IgA** constitutes about 10-15% of serum immunoglobulins, ranking second to IgG in concentration. - While abundant in serum, its primary functional significance lies in its dimeric form (**Secretory IgA**) found in mucosal secretions, protecting epithelial surfaces.*IgE* - **IgE** is the immunoglobulin present at the lowest serum concentration (trace amounts). - It is mainly bound to **mast cells** and **basophils** and is responsible for mediating immediate **Type I hypersensitivity** reactions (allergies).

Q: Which among the following helps in the maturation of collagen?

Ascorbic acid. ***Ascorbic acid***- Ascorbic acid (Vitamin C) is an essential cofactor for **prolyl hydroxylase** and **lysyl hydroxylase** enzymes, which hydroxylate proline and lysine residues in procollagen.- This **hydroxylation** is critical for stabilizing the collagen triple helix structure, a necessary step for proper collagen maturation and secretion.*Proline*- **Proline** (along with glycine and lysine) is a major amino acid component of the **collagen triple helix structure**.- While essential for collagen synthesis, proline itself is a substrate, not the **cofactor** required for the crucial hydroxylation steps necessary for maturation stabilization.*Copper and zinc*- **Copper** is a required cofactor for **lysyl oxidase**, the enzyme responsible for creating *covalent cross-links* between collagen molecules, which is a late-stage event for tensile strength.- Although cross-linking is part of the overall maturation process (extracellular), **ascorbic acid's** role in the intracellular hydroxylation of procollagen is a more fundamental step in maturation.*Phenylalanine*- **Phenylalanine** is an essential aromatic amino acid primarily used in protein synthesis and as a precursor for **tyrosine**.- It plays no direct role as a **cofactor** or required structural component in the specialized post-translational modification and subsequent maturation of collagen.

Q: Which of the following cell pathways occurs exclusively in cell cytoplasm?

Glycolysis. ***Glycolysis***- Glycolysis is the metabolic pathway converting **glucose** to **pyruvate** and occurs entirely within the **cytoplasm** (cytosol) [1].- This pathway is crucial for producing ATP both in the presence (aerobic) and absence (anaerobic) of oxygen [3].*Beta oxidation*- **Beta oxidation**, the breakdown of fatty acids, occurs primarily within the **mitochondrial matrix**.- Long-chain fatty acid activation occurs in the cytosol, but the subsequent oxidative steps are confined to the **mitochondria**.*TCA cycle*- The **TCA cycle** (Krebs cycle) is located exclusively within the **mitochondrial matrix** in eukaryotic cells.- It is responsible for the complete oxidation of acetyl-CoA, producing electron carriers like **NADH** and **FADH2**.*Urea cycle*- The **urea cycle** occurs across **two distinct cellular compartments**: reactions take place in both the **mitochondrial matrix** and the **cytosol** [2].- Specifically, the synthesis of **carbamoyl phosphate** and citrulline occurs in the mitochondria [2].

Q: Nitric oxide is synthesized from which of the following amino acids?

Arginine. ***Arginine*** - **L-arginine** is the sole biological precursor for nitric oxide (NO), a crucial signaling molecule involved in vasodilation, neurotransmission, and immune response. - The synthesis is catalyzed by the family of enzymes known as **nitric oxide synthases (NOS)**, which convert L-arginine into NO and **L-citrulline**. *Tryptophan* - Tryptophan is an essential amino acid that serves primarily as the precursor for the synthesis of the neurotransmitter **serotonin** and the hormone **melatonin**. - It is metabolized via the **kynurenine pathway** and is not utilized in the reaction catalyzed by NOS. *Lysine* - Lysine is an essential amino acid important for protein synthesis, and it is a precursor for **carnitine**, which is vital for fatty acid metabolism. - It is a basic amino acid and is not the substrate required by nitric oxide synthase for NO generation. *Tyrosine* - Tyrosine is the precursor amino acid necessary for the synthesis of **catecholamines** (dopamine, norepinephrine, epinephrine) and the **thyroid hormones**. - Though part of various metabolic pathways, it is not involved in the direct enzymatic conversion that yields nitric oxide.

Q: A 16-year-old boy presented with recurrent epistaxis. There is no history of trauma associated with it. On examination, there is a firm purplish mass on the left posterior choanae. Which of the following is the most appropriate for managing this patient?

Surgical excision. ***Surgical excision***- The presentation (adolescent male, recurrent epistaxis, purplish posterior choanal mass) is classic for **Juvenile Nasopharyngeal Angiofibroma (JNA)**, a highly vascular, benign tumor.- **Surgical excision** is the definitive treatment for JNA, which is usually preceded by preoperative **embolization** to dramatically reduce the risk of severe intraoperative hemorrhage.*Needle biopsy*- Performing any blind or needle biopsy in suspected JNA is strictly **contraindicated** due to the high risk of severe, uncontrolled hemorrhage.- Diagnosis relies primarily on **clinical features** and characteristic findings on imaging (CT/MRI), which delineate the tumor's extent and vascular supply.*FNAC*- Similar to a core or punch biopsy, **FNAC (Fine Needle Aspiration Cytology)** is contraindicated due to the tumor's characteristic lack of a capillary system and abundance of large, thin-walled vessels.- This highly vascular nature means even minimal trauma can lead to profuse and life-threatening **bleeding** which can be difficult to manage. *Radiotherapy*- **Radiotherapy** is generally reserved for large, inoperable, recurrent, or residual tumors, particularly those with significant intracranial extension.- It is considered a secondary modality and is avoided as primary treatment for localized JNA due to associated risks of long-term morbidities such as **secondary malignancies** or **pituitary dysfunction** in adolescents.

Q: Which of the following dimorphic fungi causes subcutaneous mycosis?

Sporothrix schenckii. ***Sporothrix schenckii***- This dimorphic fungus is the classic causative agent of **sporotrichosis**, which is classified as a **subcutaneous mycosis** associated with inoculation injuries (e.g., from roses or hay).- Infection often presents as a primary skin lesion followed by characteristic **lymphocutaneous spread** along lymphatic channels.*Histoplasma capsulatum*- It causes **histoplasmosis**, which is primarily classified as a **systemic or deep mycosis** that is acquired by inhaling microconidia from bird or bat droppings.- Although dissemination can occur, it is not categorized as a primary subcutaneous mycosis initiated by direct wound inoculation.*Blastomyces dermatitidis*- This fungus causes **blastomycosis**, which is considered a **systemic mycosis** primarily affecting the lungs following inhalation of spores.- While disseminated disease frequently involves the skin, causing sharply demarcated verrucous lesions, the infection route remains systemic rather than purely subcutaneous.*Penicilliosis marneffei*- Now known as *Talaromyces marneffei*, it causes **talaromycosis**, which is an **opportunistic systemic mycosis** predominantly affecting immunocompromised individuals in Southeast Asia.- Though it causes diverse skin manifestations (e.g., papules, nodules), the overall clinical picture is one of deep, disseminated infection, not a localized subcutaneous mycosis like sporotrichosis.

Q: Plasma sterilization is done by

Hydrogen peroxide. ***Hydrogen peroxide*** - Plasma sterilization uses **hydrogen peroxide vapor** that is converted into plasma state by electromagnetic energy (radiofrequency or microwave) - The plasma contains **highly reactive free radicals** (hydroxyl and hydroperoxyl) that destroy microorganisms by disrupting cell membranes and DNA - Common system: **STERRAD** (Sterilization by Reactive Gas Discharge) - Advantages: **Low temperature** process (suitable for heat-sensitive instruments), **non-toxic**, leaves no residue, and has a **short cycle time** *UV rays (Incorrect)* - Used for surface disinfection and air sterilization, not plasma sterilization - Limited penetration power *Ethylene oxide (Incorrect)* - Gas sterilization method, not plasma-based - Requires longer aeration time due to toxicity *Gamma rays (Incorrect)* - Ionizing radiation sterilization method - Used for industrial sterilization, not plasma sterilization

Q: A cattle farmer presented with a lesion on the arm. Gram staining showed gram-positive rods with square ends with a central spore. Identify the organism.

Bacillus anthracis. ***Bacillus anthracis***- The microscopic finding of large, non-motile, **Gram-positive rods** with characteristic **square ends** (often described as 'boxcar' shapes) and a central spore is the classic description of *Bacillus anthracis*.- The clinical history of a **cattle farmer** with a skin lesion strongly suggests **cutaneous anthrax**, the most common form of anthrax acquired through exposure to infected livestock.*Bacillus cereus*- While also a Gram-positive, spore-forming rod, *B. cereus* is generally **motile** and typically causes severe food poisoning (emetic or diarrheal types).- It usually lacks the distinctive **square ends** seen in *Bacillus anthracis*.*Pseudomonas aeruginosa*- This organism is a **Gram-negative rod**, which directly contradicts the finding of a Gram-positive rod in the staining.- Furthermore, *P. aeruginosa* is **non-spore-forming**, ruling it out based on the finding of a central spore.*Brucella abortus*- *Brucella* species are small, obligate intracellular, **Gram-negative coccobacilli** or short rods, not large Gram-positive rods.- They are **non-spore-forming** and typically cause systemic illness (**brucellosis** or undulant fever) rather than localized cutaneous lesions matching this description.

Q: What is the function of utricle and saccule?

Linear acceleration. ***Linear acceleration***- The **utricle** and **saccule** are the two **otolithic organs** of the inner ear responsible for detecting mechanical forces related to **linear motion** (acceleration, deceleration) and the pull of gravity.- The **utricle** senses horizontal linear acceleration (e.g., walking), while the **saccule** senses vertical linear acceleration (e.g., riding an elevator).*Hearing high-frequency sounds*- Sound detection (hearing) is carried out by the **cochlea** and its associated structures, primarily the hair cells in the **Organ of Corti**.- High frequencies stimulate hair cells located near the **base** of the **basilar membrane** but this is unrelated to the vestibular functions of the utricle and saccule.*Angular acceleration*- Rotational movements of the head, or **angular acceleration**, are detected solely by the three **semicircular canals**.- The canals use the movement of endolymph to displace the **cupula** within the **ampullae**, stimulating the enclosed hair cells.*Hearing low-frequency sounds*- The **cochlea** is the auditory apparatus; the utricle and saccule are part of the **vestibular system** responsible for balance and spatial orientation.- Low frequencies primarily stimulate hair cells located near the **apex** of the **basilar membrane** (apex is furthest from the oval window).

Question 1

Identify the sinus marked in the image.

Accepted Answer

Maxillary sinus

Answer

Pyriform sinus

Answer

Ethmoid sinus

Answer

Frontal sinus

Question 2

Which of the following immunoglobulins shows the highest concentration in serum?

Accepted Answer

IgG

Answer

IgM

Answer

IgA

Answer

IgE

Question 3

Which among the following helps in the maturation of collagen?

Accepted Answer

Ascorbic acid

Answer

Proline

Answer

Copper and zinc

Answer

Phenylalanine

Question 4

Which of the following cell pathways occurs exclusively in cell cytoplasm?

Accepted Answer

Glycolysis

Answer

TCA cycle

Answer

Urea cycle

Answer

Beta oxidation

Question 5

Nitric oxide is synthesized from which of the following amino acids?

Accepted Answer

Arginine

Answer

Tryptophan

Answer

Lysine

Answer

Tyrosine

Question 6

A 16-year-old boy presented with recurrent epistaxis. There is no history of trauma associated with it. On examination, there is a firm purplish mass on the left posterior choanae. Which of the following is the most appropriate for managing this patient?

Accepted Answer

Surgical excision

Answer

Radiotherapy

Answer

FNAC

Answer

Needle biopsy

Question 7

Which of the following dimorphic fungi causes subcutaneous mycosis?

Accepted Answer

Sporothrix schenckii

Answer

Blastomyces dermatitidis

Answer

Penicilliosis marneffei

Answer

Histoplasma capsulatum

Question 8

Plasma sterilization is done by

Accepted Answer

Hydrogen peroxide

Answer

UV rays

Answer

Ethylene oxide

Answer

Gamma rays

Question 9

A cattle farmer presented with a lesion on the arm. Gram staining showed gram-positive rods with square ends with a central spore. Identify the organism.

Accepted Answer

Bacillus anthracis

Answer

Bacillus cereus

Answer

Pseudomonas aeruginosa

Answer

Brucella abortus

Question 10

What is the function of utricle and saccule?

Accepted Answer

Linear acceleration

Answer

Hearing high-frequency sounds

Answer

Hearing low-frequency sounds

Answer

Angular acceleration

FMGE 2023

Anatomy

Biochemistry

ENT

Microbiology

Physiology