NEET-PG 2013 Practice Questions

Q: What is the number of variable regions present on each light and heavy chain of an antibody?

1. ***1*** - Each **light chain** and **heavy chain** within an antibody molecule contains **one variable region (V domain)**. - These variable regions are crucial for **antigen binding specificity**, as they combine to form the antigen-binding site. - The variable domain is located at the **N-terminal end** of each chain. *2* - While a complete antibody molecule has **two antigen-binding sites** (bivalent), each formed by pairing of VH and VL domains, individual chains possess only **one variable region each**. - The number '2' refers to the total number of identical binding sites on the intact antibody, not the number of variable regions per chain. *3* - The number **3** does not correspond to the number of variable regions on individual chains. - This might be confused with the **three complementarity-determining regions (CDRs)** present within each variable domain (CDR1, CDR2, CDR3), which are hypervariable loops that directly contact the antigen. *4* - The number **4** is incorrect for variable regions. - This number corresponds to the total number of **polypeptide chains** in a complete IgG antibody (2 heavy + 2 light chains), or the number of **constant domains** in some heavy chain isotypes (IgM, IgE have 4 CH domains).

Q: What is the drug of choice for bleeding oesophageal varices?

Octreotide. ***Octreotide*** - **Octreotide** is an analogue of **somatostatin** that reduces splanchnic blood flow and portal pressure, thereby decreasing bleeding from esophageal varices. - It is often used in the acute management of **bleeding esophageal varices** due to its rapid onset of action and favorable safety profile. *Ethanolamine oleate* - **Ethanolamine oleate** is a **sclerosing agent** used for endoscopic sclerotherapy of esophageal varices, not typically as the initial drug of choice for acute bleeding [1]. - It acts by causing inflammation and fibrosis of the varices, which can be effective but carries risks such as **esophageal ulceration** or perforation. *Propranolol* - **Propranolol** is a **non-selective beta-blocker** used for the prophylactic prevention of variceal bleeding, not for acute management of active bleeding. - It works by reducing portal venous pressure by decreasing cardiac output and splanchnic vasoconstriction. *Phytonadione* - **Phytonadione** (vitamin K1) is used to reverse **coumarin anticoagulant effects** or to treat **vitamin K deficiency**, which can contribute to bleeding but is not a direct treatment for variceal bleeding itself. - It helps in the synthesis of **coagulation factors II, VII, IX, and X**, thereby improving clotting.

Q: Which gene of the hepatitis B virus has the longest coding sequence?

P gene. ***P gene*** - The **P gene** (polymerase gene) encodes the viral **reverse transcriptase**, which is crucial for replicating the HBV genome. - This enzyme is very large and complex, requiring the **longest coding sequence** to accommodate all its functional domains. *X gene* - The **X gene** encodes the **HBx protein**, which is a transcriptional transactivator and plays a role in hepatocarcinogenesis. - It has a relatively **short coding sequence** compared to the P gene. *S gene* - The **S gene** encodes the **surface antigens (HBsAg)**, which are involved in viral entry and immune evasion. - It has a **shorter coding sequence** than the P gene, as it primarily codes for structural proteins. *C gene* - The **C gene** encodes the **core protein (HBcAg)**, which forms the viral nucleocapsid, and the **HBeAg**. - Its coding sequence is also **shorter** than that of the P gene, reflecting its role in structural and regulatory functions.

Q: Which of the following is a cause of Valley fever (desert rheumatism)?

Coccidioides. ***Coccidioides*** - **Valley fever**, or desert rheumatism, is caused by infection with the dimorphic fungus **Coccidioides**, primarily **Coccidioides immitis** and **Coccidioides posadasii**. - This fungus is endemic to arid and semi-arid regions, especially the **southwestern United States** and parts of Central and South America. *Sporothrix* - **Sporothrix schenckii** causes sporotrichosis, a chronic fungal infection typically involving the skin, subcutaneous tissue, and adjacent lymphatics, often through skin trauma. - It does not cause Valley fever. *Cladosporium* - **Cladosporium** species are ubiquitous molds commonly found in outdoor and indoor environments, often associated with allergic reactions and occasionally superficial infections. - They are not a cause of Valley fever. *Phialophora* - **Phialophora** species are dematiaceous fungi that can cause phaeohyphomycosis, chromoblastomycosis, and eumycetoma, which are subcutaneous or systemic fungal infections. - They are not associated with Valley fever.

Q: Most common type of HPV associated with cervical cancer?

16, 18. ***16, 18*** - **HPV types 16 and 18** are considered **high-risk HPV types** and are responsible for approximately **70% of all cervical cancer cases** globally. - These types produce **oncoproteins E6 and E7** that interfere with tumor suppressor genes (p53 and Rb), leading to uncontrolled cell growth and malignancy. *6, 11* - **HPV types 6 and 11** are considered **low-risk HPV types** and are primarily associated with **genital warts (condyloma acuminata)**. - While they can cause benign lesions, they are **rarely associated with cervical cancer**. *5, 8* - **HPV types 5 and 8** are **cutaneous HPV types** primarily associated with **epidermodysplasia verruciformis**, a rare genetic condition predisposing to skin cancers. - These types affect the **skin** and are **not associated with cervical cancer**, making them incorrect for this question. *6, 8* - This combination includes **HPV 6**, which is a **low-risk type** primarily associated with genital warts. - **HPV 8** is a cutaneous type associated with skin lesions, not cervical cancer. - This pairing does not represent the most common types responsible for cervical cancer.

Q: Color of granules in mycetoma caused by Actinomadura pelletierrii -

Red. ***Red*** - *Actinomadura pelletierrii* is a common cause of **actinomycetoma** and is characterized by producing **red granules** in the lesions. - The color of these granules is a key diagnostic feature, helping differentiate it from other causes of mycetoma. *Black* - **Black granules** are typically associated with **eumycetoma** caused by **dematiaceous fungi** such as *Madurella mycetomatis*. - This color indicates the presence of **melanin**, a pigment produced by these fungal species. *Yellow* - **Yellow granules** are commonly seen in actinomycetoma caused by organisms such as *Nocardia brasiliensis* or sometimes *Actinomadura madurae*. - This color helps differentiate these specific actinomycetes from other types that produce different granule colors. *Brown* - While varying shades of color can occur, **brown granules** are not the characteristic color produced by *Actinomadura pelletierrii*. - Some *Streptomyces* species or certain eumycetoma agents can occasionally produce brownish granules, but red is specific for *A. pelletierrii*.

Q: Which of the following conditions is NOT caused by Aspergillus?

Dermatophytosis. ***Dermatophytosis*** - This condition is caused by **dermatophytes** (e.g., *Trichophyton*, *Microsporum*, *Epidermophyton*), which are a specific group of fungi that metabolize keratin. - *Aspergillus* species are generally **opportunistic molds** but do not typically cause dermatophytosis, which is a superficial fungal infection of the skin, hair, or nails. *Otomycosis* - **Otomycosis** is a fungal infection of the external ear canal, and *Aspergillus* species are a common cause, particularly *Aspergillus niger*. - It can lead to ear pain, discharge, itching, and hearing impairment. *Allergic sinusitis* - **Allergic fungal sinusitis (AFS)** is a common form of fungal sinusitis where *Aspergillus* species are significant contributors, often leading to a thick, tenacious allergic mucin. - This condition is an IgE-mediated hypersensitivity reaction to the fungal elements in the nasal and sinus cavities. *Bronchopulmonary allergy* - **Allergic bronchopulmonary aspergillosis (ABPA)** is a hypersensitivity reaction to *Aspergillus fumigatus* antigens that colonize the airways, particularly in individuals with asthma or cystic fibrosis. - It results in recurrent episodes of wheezing, cough, and transient pulmonary infiltrates, and can lead to bronchiectasis if left untreated.

Q: A plant prick can produce sporotrichosis. Which of the following statements about sporotrichosis is false?

It is an occupational disease of butchers, doctors. ***It is an occupational disease of butchers, doctors*** - Sporotrichosis is an **occupational hazard for gardeners, florists, and agricultural workers** due to exposure to decaying plant matter, not typically for butchers or doctors. - The disease is caused by **direct inoculation** of the fungus *Sporothrix schenckii* into the skin, often through a thorn prick or minor trauma. *Most cases are acquired via cutaneous inoculation* - This statement is **true** as sporotrichosis is primarily caused by **traumatic implantation** of fungal spores into the skin. - Common sources include **thorns, splinters, sphagnum moss**, and other plant materials. *Enlarged lymph nodes extending centripetally as a beaded chain are a characteristic finding* - This statement is **true** and describes the classic **lymphocutaneous sporotrichosis**, where lesions and **nodular lymphangitis** track along lymphatic channels. - The "beaded chain" appearance refers to the multiple subcutaneous nodules formed along the lymphatic vessels. *Is a chronic mycotic disease that typically involves skin, subcutaneous tissue and regional lymphatics* - This statement is **true** because sporotrichosis is a **slow-progressing fungal infection** that primarily affects the skin, the tissue just beneath the skin, and the lymphatics draining the infected area. - While systemic dissemination can occur in immunocompromised individuals, the **cutaneous and lymphocutaneous forms** are most common.

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

Viruses are capable of independent motility.. ***Viruses are capable of independent motility.*** - Viruses are **acellular infectious agents** and lack the cellular machinery required for independent movement or motility. - They rely on host cell processes or environmental factors for their dissemination and entry into cells. *Viruses lack ribosomes.* - Viruses are **obligate intracellular parasites**; they lack ribosomes and other cellular organelles necessary for protein synthesis. - They hijack the host cell's ribosomes and metabolic machinery to replicate their genetic material and produce viral proteins. *Viruses lack mitochondria.* - Viruses lack mitochondria, as they are **not capable of generating their own ATP** through cellular respiration. - They depend on the host cell's energy-generating systems to provide the ATP required for their replication cycle. *Viruses contain nucleic acid.* - All viruses contain a **nucleic acid genome**, which can be either DNA or RNA. - This genetic material carries the instructions for viral replication and is enclosed within a protein coat called a **capsid**.

Q: 2 months old child having birth weight 2kg, with poor feeding, very sleepy and wheezing. The diagnosis is?

Very severe disease. ***Very severe disease*** - According to **WHO/IMNCI (Integrated Management of Neonatal and Childhood Illness) classification** for young infants (0-2 months), the presence of **danger signs** automatically classifies the condition as "Very severe disease" - This infant presents with two critical danger signs: **poor feeding** and **lethargy (very sleepy)**, along with respiratory symptoms (wheezing) - In young infants, any danger sign (poor feeding, lethargic/unconscious, convulsions, severe chest indrawing, central cyanosis) requires immediate classification as "Very severe disease" and **urgent referral** to higher center - This is a specific diagnostic classification used in pediatric emergency protocols, not a general term *Severe respiratory infection* - While the child has respiratory symptoms (wheezing), this classification would only be appropriate if respiratory distress was present **without danger signs** - The presence of danger signs (poor feeding, lethargy) escalates the classification to "Very severe disease" in the WHO/IMNCI protocol - In young infants (0-2 months), the classification system prioritizes danger signs over organ-specific diagnoses *No evidence of pneumonia* - This is incorrect as the infant clearly presents with respiratory symptoms (wheezing) and systemic signs of illness - The presence of wheezing, poor feeding, and lethargy indicates serious illness requiring urgent evaluation and treatment - This option contradicts the clinical presentation *No diagnosis* - This is incorrect as the WHO/IMNCI classification provides a clear diagnostic framework - The presence of danger signs in a young infant mandates classification as "Very severe disease" - A working diagnosis is essential for guiding appropriate management and urgent referral

Question 1

What is the number of variable regions present on each light and heavy chain of an antibody?

Accepted Answer

1

Answer

2

Answer

3

Answer

4

Question 2

What is the drug of choice for bleeding oesophageal varices?

Accepted Answer

Octreotide

Answer

Ethanolamine oleate

Answer

Propanolol

Answer

Phytonadione

Question 3

Which gene of the hepatitis B virus has the longest coding sequence?

Accepted Answer

P gene

Answer

X gene

Answer

S gene

Answer

C gene

Question 4

Which of the following is a cause of Valley fever (desert rheumatism)?

Accepted Answer

Coccidioides

Answer

Sporothrix

Answer

Cladosporium

Answer

Phialophora

Question 5

Most common type of HPV associated with cervical cancer?

Accepted Answer

16, 18

Answer

6, 11

Answer

5, 8

Answer

6, 8

Question 6

Color of granules in mycetoma caused by Actinomadura pelletierrii -

Accepted Answer

Red

Answer

Black

Answer

Yellow

Answer

Brown

Question 7

Which of the following conditions is NOT caused by Aspergillus?

Accepted Answer

Dermatophytosis

Answer

Otomycosis

Answer

Allergic sinusitis

Answer

Bronchopulmonary allergy

Question 8

A plant prick can produce sporotrichosis. Which of the following statements about sporotrichosis is false?

Accepted Answer

It is an occupational disease of butchers, doctors

Answer

Enlarged lymph nodes extending centripetally as a beaded chain are a characteristic finding

Answer

Most cases are acquired via cutaneous inoculation

Answer

Is a chronic mycotic disease that typically involves skin, subcutaneous tissue and regional lymphatics

Question 9

Which of the following statements about viruses is false?

Accepted Answer

Viruses are capable of independent motility.

Answer

Viruses contain nucleic acid.

Answer

Viruses lack mitochondria.

Answer

Viruses lack ribosomes.

Question 10

2 months old child having birth weight 2kg, with poor feeding, very sleepy and wheezing. The diagnosis is?

Accepted Answer

Very severe disease

Answer

No evidence of pneumonia

Answer

Severe respiratory infection

Answer

No diagnosis

NEET-PG 2013

Biochemistry

Internal Medicine

Microbiology

Pediatrics