NEET-PG 2018 Practice Questions

Q: Which chromosome is responsible for the production of MIF?

Chromosome 22. ***Chromosome 22*** * The **macrophage migration inhibitory factor (MIF)** gene is located on **chromosome 22q11.2**, making it responsible for MIF production. * MIF is a crucial **pro-inflammatory cytokine** involved in immune responses and inflammation. *Chromosome 16* * Chromosome 16 contains genes like those for **alpha-globin** and **CDH1 (E-cadherin)**, not MIF. * Disorders associated with chromosome 16 include **alpha-thalassemia** and certain types of **hereditary diffuse gastric cancer**. *X Chromosome* * The X chromosome contains genes primarily involved in **sex determination** and various X-linked disorders. * Examples include genes like **DMD (Duchenne muscular dystrophy)** and **F8 (hemophilia A)**, but not MIF. *Y chromosome* * The Y chromosome contains genes, such as **SRY (sex-determining region Y)**, that are critical for male sexual development. * It plays a role in male-specific traits and conditions like **infertility** but does not carry the gene for MIF.

Q: Which of the following statements about DNA polymerase I is correct?

Involved in DNA repair processes.. ***Involved in DNA repair processes.*** - **DNA polymerase I** possesses **5' to 3' exonuclease activity**, which is crucial for removing **RNA primers** and damaged DNA segments during DNA repair. - Its **DNA repair function** is essential for maintaining genome integrity by excising incorrect nucleotides and filling the gaps. - DNA pol I plays a key role in **nick translation** and **gap filling** after primer removal during DNA replication. *Participates in the synthesis of Okazaki fragments.* - **DNA polymerase III** is the primary enzyme responsible for synthesizing **Okazaki fragments** on the lagging strand during bacterial DNA replication. - While DNA polymerase I does **process** Okazaki fragments by removing RNA primers and filling gaps, it does not *synthesize* them. *Is the primary enzyme for DNA replication in bacteria* - **DNA polymerase III** is the main enzyme responsible for the bulk of DNA synthesis during replication in **bacteria**. - DNA polymerase I plays a more specialized role in **primer removal** and **gap filling** rather than primary elongation. *Not essential for DNA replication in bacteria.* - **DNA polymerase I** is **essential** for bacterial viability despite not being the primary replicative polymerase. - Its crucial role in **primer removal** and **gap filling** after primer excision is indispensable for completing DNA replication and repair processes.

Q: Which of the following statements is true regarding Hemophilia A?

Deficiency of factor VIII. ***Serum levels of factor VIII are decreased*** - Hemophilia A is characterized by a **deficiency of factor VIII** [1], which leads to decreased serum levels of this factor. - This deficiency results in a **prolonged activated partial thromboplastin time (aPTT)** [3] but normal prothrombin time (PT). *Deficiency of factor IX* - This escribes **Hemophilia B**, which is caused by a deficiency of factor IX, not factor VIII as in Hemophilia A [1]. - Hemophilia A specifically refers to the **deficiency of factor VIII** [1][2], where factor IX is not involved. *PT increased* - In Hemophilia A, the **prothrombin time (PT)** is usually normal because the intrinsic pathway is not affected [3]. - The primary test affected is the **activated partial thromboplastin time (aPTT)**, which is prolonged due to factor VIII deficiency [3]. *FIT decreased* - The term "FIT" is not standard in the context of hemophilia; it might refer to some other tests or assessments not directly relevant to factor levels. - The relevant lab finding in Hemophilia A is the **decrease in factor VIII** [2], not a direct measure of "FIT".

Q: In Bartter syndrome defect is seen in:

Defect in thick ascending limb of loop of Henle. ***Defect in thick ascending limb of loop of Henle*** - Bartter syndrome results from a **genetic defect** affecting the activity of the **Na-K-2Cl cotransporter (NKCC2)** in the thick ascending limb of the loop of Henle. - This defect impairs **sodium, potassium, and chloride reabsorption**, leading to their increased excretion and characteristic electrolyte imbalances. *Defect in proximal convoluted tubule (PCT)* - Defects in the **proximal convoluted tubule** are typically associated with conditions like **Fanconi syndrome**, affecting reabsorption of glucose, amino acids, phosphate, and bicarbonate [1]. - This does not align with the characteristic **electrolyte imbalances** seen in Bartter syndrome, particularly hypokalemia and metabolic alkalosis. *Defect in distal convoluted tubule (DCT)* - Defects in the **distal convoluted tubule** are seen in conditions like **Gitelman syndrome**, which affects the Na-Cl cotransporter. - While both Bartter and Gitelman syndromes present with hypokalemia and metabolic alkalosis, the specific transporter affected and the severity of certain electrolyte disturbances differ. *No defect* - Bartter syndrome is a well-defined **genetic disorder** characterized by specific renal tubular defects. - Stating there is no defect is incorrect, as the syndrome arises directly from impaired renal tubule function.

Q: Extramammary Paget's disease of the vulva is most commonly associated with which other cancer?

Vulvar cancer. ***Vulvar cancer*** - **Extramammary Paget's disease (EMPD)** frequently presents in the vulvar region and is associated with an underlying **adenocarcinoma** in up to 30% of cases. - The disease involves intraepithelial adenocarcinoma cells that can spread locally and, in some instances, indicates a synchronous or metachronous **internal malignancy**, often of genitourinary or gastrointestinal origin, but primarily vulvar adenocarcinoma in this context. *Vaginal cancer* - While Paget's disease can occur in other anogenital areas, its association with **primary vaginal cancer** is much less common compared to vulvar involvement. - **Vaginal Paget's disease** is rare and usually represents secondary spread from a vulvar primary or an underlying bladder/urethral carcinoma. *Cervical cancer* - **Paget's disease** is not typically associated with **cervical cancer**. Cervical cancers are predominantly squamous cell carcinomas or adenocarcinomas arising from the transformation zone. - While cervical adenocarcinoma can present with similar cells to Paget's, it is a distinct entity and not a common association. *Uterine cancer* - **Uterine cancer**, primarily endometrial carcinoma, has no direct or common association with **Paget's disease**. - Paget's disease primarily affects the skin and can be associated with underlying gland cancers, but these are generally in proximity to the epidermal involvement rather than distant uterine sites.

Q: Which of the following is not a high-risk pregnancy?

Age 25-30 years. ***Age 25-30 years*** - An age of **25-30 years** is generally considered the optimal reproductive age range, and pregnancies within this bracket are typically classified as low-risk based on age alone. - This age range carries the lowest statistical risk for both maternal and fetal complications, assuming no other co-morbidities. *Previous history of manual removal of placenta* - A previous history of manual removal of the placenta indicates a risk factor for **recurrent placental retention** or **morbidly adherent placenta** in future pregnancies, making it a high-risk factor. - This history suggests an increased likelihood of complications such as **postpartum hemorrhage** and can influence the management of subsequent deliveries. *Anemia* - **Anemia** in pregnancy, especially severe iron deficiency anemia, is considered a high-risk factor due to increased maternal and fetal morbidity. - It can lead to complications such as **preterm delivery**, **low birth weight**, and difficulties tolerating blood loss during delivery. *Diabetes mellitus* - **Diabetes mellitus**, whether pre-existing or gestational, makes a pregnancy high-risk due to potential adverse effects on both the mother and the fetus. - Risks include **preeclampsia**, **macrosomia**, **neonatal hypoglycemia**, and **congenital anomalies**.

Q: In which type of Hodgkin's lymphoma are classical Reed-Sternberg cells most characteristically observed?

Mixed cellularity Hodgkin. ***Lymphocyte predominance*** - The **Hodgkin's lymphoma (HL) lymphocyte predominance** variant characteristically displays a predominance of lymphocytes in the cellular makeup [1]. - This subtype is often associated with a better prognosis and fewer symptoms than other types of HL [1]. *Lymphocyte depleted* - This subtype features a significant decrease in lymphocytes, leading to a **higher proportion of Reed-Sternberg cells** [3]. - It typically presents with a more aggressive clinical course, which contrasts with lymphocyte predominance [3]. *Mixed cellularity hodgkin* - Mixed cellularity shows a variety of cell types, including a significant number of **Reed-Sternberg cells**, but does not demonstrate **lymphocyte predominance** [2]. - This subtype is generally found in older patients and associated with advanced disease, unlike lymphocyte predominance [2]. *Nodular sclerosis* - Nodular sclerosis subtype is characterized by **collagen bands** and a particular architecture that is distinct from lymphocyte predominance [2]. - It primarily affects younger patients and can often involve mediastinal lymph nodes; however, it does not have the features of lymphocyte predominance [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 618. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 616-618. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 559-560.

Q: Which condition is associated with congenital adrenal hyperplasia?

Female pseudohermaphroditism. ***Female pseudohermaphroditism*** - In **21-hydroxylase deficiency**, the most common form of CAH, virilization of a female fetus occurs due to excessive **androgen production** [2], [3]. - This leads to ambiguous genitalia in genetically female (XX) infants, presenting as **female pseudohermaphroditism** [2]. *Male pseudohermaphroditism* - This condition occurs when a **genetically male individual (XY)** has external genitalia that are undervirilized or ambiguous. - It is typically caused by inadequate **androgen synthesis** or action, such as in **androgen insensitivity syndrome**, which is not the primary presentation of CAH [2]. *True pseudohermaphroditism* - This term refers to individuals who possess both **ovarian and testicular tissue**, either in separate gonads or as ovotestes [1], [2]. - It is distinct from CAH, where gonadal tissue is uniform (either ovaries or testes), but the external genitalia are ambiguous due to hormonal imbalances [2]. *Sequential pseudohermaphroditism* - This term is not a recognized medical classification for conditions like CAH. - It does not describe a specific developmental anomaly of the reproductive system related to adrenal function.

Q: Endothelin primarily acts through which type of receptors?

Endothelin receptor type A (ETA). ***Endothelin receptor type A (ETA)*** - **ETA receptors** are primarily responsible for the **vasoconstrictive effects** of endothelin-1 in various tissues, leading to increased vascular tone and blood pressure. - Activation of **ETA receptors** on vascular smooth muscle cells mediates signaling pathways that result in **smooth muscle contraction**. *Endothelin receptor type B (ETB)* - **ETB receptors** have dual roles, mediating both **vasoconstriction** (via smooth muscle ETB) and **vasodilation** (via endothelial ETB, stimulating nitric oxide and prostacyclin release). - They also play a significant role in **clearance of endothelin-1** from circulation. *General receptor type (GPCRs)* - While **endothelin receptors (ETA and ETB)** are indeed **G protein-coupled receptors (GPCRs)**, "General receptor type (GPCRs)" is too broad and not the most specific answer for how endothelin *primarily acts*. - Endothelin's specific effects are mediated through its dedicated subtypes of GPCRs, not the general class. *Calcium receptors* - **Calcium receptors** (e.g., calcium-sensing receptors) are involved in sensing extracellular calcium levels and regulating calcium homeostasis. - Endothelin's mechanism involves **intracellular calcium mobilization** *after* receptor activation, but it does not act *through* calcium receptors.

Q: What is the physiological response of the kidney during shock?

Renal blood flow decreases. ***Renal blood flow decreases*** - During shock, the **primary and most fundamental** physiological change affecting the kidney is a marked **reduction in renal blood flow (RBF)**. - Shock triggers intense **sympathetic activation** and **renin-angiotensin system (RAS) activation**, causing preferential **vasoconstriction** of renal vessels to redirect blood to vital organs (brain, heart). - RBF can drop to as low as **20-30% of normal** in severe shock, making this the hallmark renal response. - This reduction in RBF is the **upstream event** that triggers all other renal changes during shock. *Perfusion of kidney decreases* - While technically correct, "decreased perfusion" is **essentially synonymous** with decreased blood flow in this context. - The term "renal blood flow" is the **standard physiological terminology** used in medical literature to describe this phenomenon, making it the more precise answer. *Afferent arteriole resistance increases* - This is a **mechanism** by which RBF decreases, not the overall response itself. - Increased afferent arteriolar resistance is **secondary** to sympathetic activation and angiotensin II effects during shock. - It describes the "how" rather than the "what" of the kidney's response. *GFR decreases* - GFR reduction is a **consequence** of decreased RBF and increased afferent arteriolar resistance. - While clinically important (oliguria/acute kidney injury), it's a **downstream effect** rather than the primary physiological response. - The relationship: ↓RBF → ↓Glomerular hydrostatic pressure → ↓GFR

Question 1

Which chromosome is responsible for the production of MIF?

Accepted Answer

Chromosome 22

Answer

Y chromosome

Answer

Chromosome 16

Answer

X Chromosome

Question 2

Which of the following statements about DNA polymerase I is correct?

Accepted Answer

Involved in DNA repair processes.

Answer

Participates in the synthesis of Okazaki fragments.

Answer

Is the primary enzyme for DNA replication in bacteria

Answer

Not essential for DNA replication in bacteria.

Question 3

Which of the following statements is true regarding Hemophilia A?

Accepted Answer

Deficiency of factor VIII

Answer

PT is typically prolonged

Answer

PTT is typically normal

Answer

Serum levels of factor VIII are increased

Question 4

In Bartter syndrome defect is seen in:

Accepted Answer

Defect in thick ascending limb of loop of Henle

Answer

Defect in proximal convoluted tubule (PCT)

Answer

Defect in distal convoluted tubule (DCT)

Answer

No defect

Question 5

Extramammary Paget's disease of the vulva is most commonly associated with which other cancer?

Accepted Answer

Vulvar cancer

Answer

Vaginal cancer

Answer

Cervical cancer

Answer

Uterine cancer

Question 6

Which of the following is not a high-risk pregnancy?

Accepted Answer

Age 25-30 years

Answer

Diabetes mellitus

Answer

Previous history of manual removal of placenta

Answer

Anemia

Question 7

In which type of Hodgkin's lymphoma are classical Reed-Sternberg cells most characteristically observed?

Accepted Answer

Mixed cellularity Hodgkin

Answer

Lymphocyte depleted

Answer

Nodular sclerosis

Answer

Lymphocyte predominance

Question 8

Which condition is associated with congenital adrenal hyperplasia?

Accepted Answer

Female pseudohermaphroditism

Answer

Male pseudohermaphroditism

Answer

True pseudohermaphroditism

Answer

Sequential pseudohermaphroditism

Question 9

Endothelin primarily acts through which type of receptors?

Accepted Answer

Endothelin receptor type A (ETA)

Answer

Calcium receptors

Answer

General receptor type (GPCRs)

Answer

Endothelin receptor type B (ETB)

Question 10

What is the physiological response of the kidney during shock?

Accepted Answer

Renal blood flow decreases

Answer

GFR decreases

Answer

Perfusion of kidney decreases

Answer

Afferent arteriole resistance increases

NEET-PG 2018

Biochemistry

Internal Medicine

Obstetrics and Gynecology

Pathology

Pediatrics

Physiology