NEET-PG 2012 Practice Questions

Q: Renal papilla opens into -

Minor calyx. ***Minor calyx*** - The **renal papilla** is the apex of the renal pyramid, which drains urine directly into a **minor calyx**. - Minor calyces then merge to form major calyces, eventually leading to the renal pelvis. *Cortex* - The **renal cortex** is the outer layer of the kidney, containing glomeruli and convoluted tubules, and does not directly receive urine from the papilla. - Urine is primarily formed and filtered in the cortex and then flows into the medulla. *Pyramid* - A **renal pyramid** is a conical structure within the renal medulla, and the renal papilla is its tip, but it doesn't open *into* the pyramid itself. - Instead, the pyramid *contains* the structures that contribute to the papilla. *Major calyx* - A **major calyx** is formed by the convergence of several minor calyces. - The renal papilla drains into the minor calyx, which then, in turn, drains into the major calyx.

Q: Which is derived from Wolffian duct?

Appendix of epididymis. The **appendix of the epididymis** is a vestigial structure directly derived from the mesonephric (Wolffian) duct in males. It is an embryological remnant of this duct, located at the head of the epididymis. *Appendix of the testis* - The **appendix of the testis** (hydatid of Morgagni) is a remnant of the paramesonephric (Müllerian) duct, not the Wolffian duct. - It is usually found on the upper pole of the testis, typically near the epididymis. *Uterine structure* - **Uterine structures** (uterus, fallopian tubes, and upper vagina) are derived from the paramesonephric (Müllerian) ducts in females [1]. - The Wolffian ducts largely regress in females due to the absence of testosterone. *Hydatid of Morgagni* - The term **hydatid of Morgagni** can refer to the appendix of the testis (Müllerian duct remnant) or, less commonly, to the appendix of the epididymis (Wolffian duct remnant). - However, in common clinical and anatomical usage, it almost exclusively refers to the **appendix of the testis**, which is a Müllerian duct derivative.

Q: The rate-limiting step in glycolysis is catalyzed by?

Phosphofructokinase. ***Phosphofructokinase*** - **Phosphofructokinase-1 (PFK-1)** is the primary regulatory enzyme and **rate-limiting step** in glycolysis. - It catalyzes the irreversible phosphorylation of **fructose-6-phosphate to fructose-1,6-bisphosphate**, a crucial commitment step. *Enolase* - **Enolase** catalyzes the conversion of **2-phosphoglycerate to phosphoenolpyruvate** in glycolysis. - While essential for glycolysis, it is not the rate-limiting step. *Glucokinase* - **Glucokinase** catalyzes the phosphorylation of glucose to **glucose-6-phosphate** in the liver and pancreatic beta cells. - This is the first step in glycolysis but is not the rate-limiting step for the entire pathway once glucose has entered the cell. *Pyruvate kinase* - **Pyruvate kinase** catalyzes the final step of glycolysis, converting **phosphoenolpyruvate to pyruvate**. - Although it is a regulated enzyme, it is not the primary rate-limiting step that controls the overall flux through the glycolytic pathway.

Q: Which reaction requires Vitamin B1?

Oxidative decarboxylation. ***Oxidative decarboxylation*** - Vitamin B1, in its active form **thiamine pyrophosphate (TPP)**, is a crucial coenzyme for enzymes catalyzing **oxidative decarboxylation** reactions. - Key examples include the **pyruvate dehydrogenase complex** and **alpha-ketoglutarate dehydrogenase complex**, essential for cellular respiration and the citric acid cycle. *Transamination* - This type of reaction, involving the transfer of an **amino group**, primarily requires **pyridoxal phosphate (PLP)**, the active form of **Vitamin B6**. - It is vital for amino acid metabolism but does not utilize Vitamin B1. *Carboxylation* - **Carboxylation** reactions, which add a carboxyl group to a substrate, typically require **biotin** (Vitamin B7) as a coenzyme. - Examples include pyruvate carboxylase and acetyl-CoA carboxylase, which are not dependent on Vitamin B1. *None of the options* - As **oxidative decarboxylation** specifically requires Vitamin B1, this option is incorrect. - The other listed reactions depend on different vitamins as coenzymes.

Q: Cell-matrix adhesions are mediated by?

Integrins. ***Integrins*** - **Integrins** are transmembrane receptors that mediate cell adhesion to the **extracellular matrix (ECM)**, linking it to the cell's cytoskeleton. - They bind to various ECM components like **fibronectin**, **collagen**, and **laminin**. *Cadherins* - **Cadherins** are primarily involved in **cell-to-cell adhesion**, forming junctions like **adherens junctions** and **desmosomes**. - They are **calcium-dependent adhesion molecules** that do not directly bind to the extracellular matrix. *Selectins* - **Selectins** are cell adhesion molecules involved in **leukocyte rolling** and **adhesion to endothelial cells** during inflammation. - They mediate **transient cell-to-cell interactions**, not cell-matrix adhesion. *Calmodulin* - **Calmodulin** is a **calcium-binding protein** that acts as a signal transducer, regulating various intracellular processes. - It is involved in **calcium-dependent signaling pathways** and enzyme activation, not cell adhesion.

Q: In a measles outbreak, measles vaccine can be given to infants at what age range:

6-9 months. ***6-9 months*** - During a **measles outbreak**, infants as young as **6 months** can receive an early dose of the measles vaccine to provide protection. - This early vaccination is crucial in high-risk situations, even though the standard first dose is typically given at **12-15 months** of age. *2-3 months* - Administering the measles vaccine at **2-3 months** is generally avoided because of the presence of persistent **maternal antibodies**. - These antibodies can interfere with the infant's immune response to the vaccine, making it less effective. *3-5 months* - Similar to the 2-3 month range, **maternal antibodies** are still likely present and at sufficiently high levels in infants aged 3-5 months. - This interference reduces the vaccine's efficacy and the likelihood of developing a robust, lasting immune response. *2-7 months* - While this range includes the accepted 6-month age for early vaccination, infants under **6 months** still pose a challenge due to **maternal antibody interference**. - Combining these ages into a single range doesn't differentiate between the reduced efficacy in younger infants versus the permissible early vaccination at 6 months and older during an outbreak.

Q: What is the primary virulence factor of Neisseria gonorrhoeae?

Pili (fimbriae). ***Pili (fimbriae)*** - **Pili are the PRIMARY virulence factor** of *Neisseria gonorrhoeae*, essential for **initial attachment and colonization** of urogenital mucosa - Enable bacteria to **adhere to non-ciliated epithelial cells**, resisting mechanical clearance by urination and secretions - Undergo **antigenic variation** to evade host immune responses - Without pili, *N. gonorrhoeae* cannot establish infection *Endotoxin (lipooligosaccharide)* - *N. gonorrhoeae* possesses **LOS (lipooligosaccharide)** which causes inflammation and tissue damage - While important for pathogenesis, it is a **secondary virulence factor** - LOS contributes to symptoms but cannot cause infection without prior colonization via pili *Exotoxin* - *N. gonorrhoeae* does **not produce significant exotoxins** - Pathogenicity is mediated through **adherence factors (pili), LOS, and surface proteins** rather than secreted protein toxins - This is not a mechanism of gonococcal virulence *All of the above are incorrect* - This statement is false as **pili (fimbriae)** are definitively the primary virulence factor for *N. gonorrhoeae*

Q: Transitional cell carcinoma of the bladder is associated with which of the following?

None of the options. ***Schistosomiasis*** - Schistosomiasis, particularly from *Schistosoma haematobium*, is a well-known risk factor for **transitional cell carcinoma of the bladder** due to chronic irritation and inflammation [1]. - The association arises due to the **presence of eggs in the bladder**, leading to calcification and eventually cancer development. *Malaria* - Malaria is primarily associated with **hemolytic anemia** and does not have a direct correlation with **bladder cancer**. - Its causative agents, *Plasmodium* species, do not typically lead to **urological malignancies** like transitional cell carcinoma. *Ascarasis* - Ascarasis, caused by *Ascaris lumbricoides*, primarily affects the **intestines** and is more associated with gastrointestinal issues. - There is no significant link between ascarasis and the **development of bladder cancer**. *Any of d above* - As this option suggests all listed conditions, it incorrectly implies that **malaria** and **ascarasis** are linked to bladder cancer, which they are not. - Transitional cell carcinoma is specifically associated with **schistosomiasis**, making this option misleading. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lower Urinary Tract and Male Genital System, pp. 968-970.

Q: What is the most common presentation of tuberculosis (TB) in children?

Hilar adenopathy. ***Hilar adenopathy*** - **Hilar adenopathy** is the most common radiographic finding in children with **primary tuberculosis**, reflecting lymph node involvement. - This is often accompanied by a small parenchymal lesion, forming the **Ghon complex**. *Abscess* - While TB can cause abscesses (e.g., cold abscesses in bone or soft tissue), it's not the **most common initial presentation** of primary childhood TB. - Abscess formation suggests a more **advanced or extrapulmonary** manifestation. *Consolidation* - **Consolidation** can be seen in adult-type or progressive primary TB, but it is less frequent than hilar adenopathy as the **initial presentation** in children. - It indicates **pneumonia-like changes** due to parenchymal inflammation. *CNS tuberculosis* - **Central Nervous System (CNS) tuberculosis** (e.g., tuberculous meningitis or tuberculoma) is a severe, extrapulmonary form of TB. - It is a **serious complication** rather than the most common initial presentation in children.

Q: Half-life of iodine-131 is

8 days. ***8 days*** - The half-life of **iodine-131** is approximately 8.02 days, which makes it suitable for both diagnostic imaging and therapeutic applications in thyroid conditions. - This specific half-life allows sufficient time for the isotope to localize in the thyroid gland and deliver a therapeutic dose, while also ensuring it clears from the body relatively quickly to minimize long-term radiation exposure. *8 hours* - A half-life of 8 hours would be too short for many therapeutic applications of iodine-131, as it would decay too rapidly to deliver an effective dose to the thyroid. - Isotopes with such short half-lives are typically used for diagnostic imaging where rapid clearance and minimal patient exposure are paramount, such as **technetium-99m**. *8 weeks* - A half-life of 8 weeks would be excessively long for clinical use of iodine-131, leading to prolonged radiation exposure for the patient. - Such long half-lives increase the risk of adverse effects from cumulative radiation, making it unsuitable for routine diagnostic or therapeutic procedures. *8 months* - A half-life of 8 months is impractically long for any medical application requiring regular administration, as it would lead to very high and persistent radiation doses. - This duration would result in significant and unacceptable long-term radiation hazards, making its use unfeasible for imaging or therapy.

Question 1

Renal papilla opens into -

Accepted Answer

Minor calyx

Answer

Cortex

Answer

Pyramid

Answer

Major calyx

Question 2

Which is derived from Wolffian duct?

Accepted Answer

Appendix of epididymis

Answer

Appendix of the testis

Answer

Uterine structure

Answer

Hydatid of Morgagni

Question 3

The rate-limiting step in glycolysis is catalyzed by?

Accepted Answer

Phosphofructokinase

Answer

Enolase

Answer

Glucokinase

Answer

Pyruvate kinase

Question 4

Which reaction requires Vitamin B1?

Accepted Answer

Oxidative decarboxylation

Answer

None of the options

Answer

Carboxylation

Answer

Transamination

Question 5

Cell-matrix adhesions are mediated by?

Accepted Answer

Integrins

Answer

Selectins

Answer

Calmodulin

Answer

Cadherins

Question 6

In a measles outbreak, measles vaccine can be given to infants at what age range:

Accepted Answer

6-9 months

Answer

2-3 months

Answer

3-5 months

Answer

2-7 months

Question 7

What is the primary virulence factor of Neisseria gonorrhoeae?

Accepted Answer

Pili (fimbriae)

Answer

All of the above are incorrect

Answer

Endotoxin (lipooligosaccharide)

Answer

Exotoxin

Question 8

Transitional cell carcinoma of the bladder is associated with which of the following?

Accepted Answer

None of the options

Answer

Malaria

Answer

Schistosomiasis

Answer

Ascariasis

Question 9

What is the most common presentation of tuberculosis (TB) in children?

Accepted Answer

Hilar adenopathy

Answer

Abscess

Answer

Consolidation

Answer

CNS tuberculosis

Question 10

Half-life of iodine-131 is

Accepted Answer

8 days

Answer

8 hours

Answer

8 weeks

Answer

8 months

NEET-PG 2012

Anatomy

Biochemistry

Community Medicine

Microbiology

Pathology

Pediatrics

Radiology