NEET-PG 2015 Practice Questions

Q: Which gene is responsible for the production of COX type 3?

COX I gene. ***COX I gene*** - COX-3 is an **alternatively spliced variant** of the **COX-1 gene** (specifically, a splice variant of the COX-1 mRNA that retains intron 1). - While it was initially thought to be a distinct gene, research has shown that it arises from the same genetic locus as COX-1. *COX 2 gene* - The COX-2 gene encodes for the **inducible cyclooxygenase enzyme**, which is responsible for prostaglandin synthesis during inflammation. - It is a separate gene from COX-1 and has distinct regulatory mechanisms and physiological roles. *COX 3 gene* - There is currently **no distinct gene in humans** specifically identified as "COX-3". - COX-3 refers to a protein isoform derived from the COX-1 gene, not a separate genetic locus. *None of the above* - This option is incorrect because COX-3 is indeed derived from the **COX-1 gene** through alternative splicing. - The existence of COX-3 as a distinct protein product has been demonstrated, although its precise physiological role in humans is still under investigation.

Q: Which of the following is true regarding carcinoid tumor?

Neuroendocrine tumor. ### Most common site is lung - Carcinoid tumors are more commonly found in the **gastrointestinal tract**, specifically the appendix and ileum, rather than the lungs [1]. - This statement is false as they can occur in the lungs but are not the most common site overall. ### Potentially malignant tumor - Carcinoid tumors can be classified as **malignant,** especially if they show aggressive behavior or metastasis. - Many carcinoid tumors, particularly those in the gastrointestinal tract, can be **non-functional** and less aggressive [1]. ### Neuroendocrine tumor - Carcinoid tumors are indeed a type of **neuroendocrine tumor**, arising from **neuroendocrine cells**. - This classification emphasizes their origin and potential for secretion of hormones like **serotonin**. ### Associated with serotonin production - Many carcinoid tumors produce **serotonin**, leading to symptoms like **carcinoid syndrome** when they metastasize, particularly to the liver [1]. - This statement is true, indicating their involvement in neuroendocrine secretions.

Q: Which type of thyroid cancer is associated with primary hyperparathyroidism and phaeochromocytoma?

Medullary carcinoma of the thyroid. ***Medullary carcinoma of the thyroid*** - Associated with **multiple endocrine neoplasia (MEN) syndrome type 2**, which includes primary hyperparathyroidism and phaeochromocytoma [1]. - Medullary carcinoma arises from **C cells** (parafollicular cells) and is linked with **elevated calcitonin** levels. *Papillary carcinoma of the thyroid* - The most common type of thyroid cancer, but **not associated** with MEN syndromes. - Typically presents as a solitary **nodule** and is linked with **radiation exposure** rather than endocrine syndromes. *Anaplastic carcinoma of the thyroid* - A highly aggressive and undifferentiated form of thyroid cancer, often associated with **poor prognosis**. - Usually arises in older adults and does not have associations with **hyperparathyroidism** or phaeochromocytoma. *Follicular carcinoma of the thyroid* - Characterized by **thyroid follicle formation** and can be associated with **iodine deficiency**, but not with MEN syndromes. - It usually presents as a **solitary thyroid nodule** and lacks connection with **primary hyperparathyroidism**.

Q: Fibrosis associated with liver cirrhosis is mediated by -

Transforming Growth Factor-beta (TGF-β). ***PDGF*** - Platelet-Derived Growth Factor (**PDGF**) is a critical mediator in the **fibrogenic response** associated with liver cirrhosis [1]. - It stimulates the **proliferation** and activation of hepatic stellate cells, leading to excessive **collagen deposition** and fibrosis [1][2]. *ICAM-1* - Intercellular Adhesion Molecule-1 (**ICAM-1**) primarily mediates **cell adhesion** and is involved in inflammatory processes, not directly in fibrosis. - While it may play a role in **leukocyte recruitment**, it does not contribute significantly to the fibrogenic pathway in liver cirrhosis. *PcAM-l* - **PCAM-1** (Platelet/endothelial cell adhesion molecule-1) is involved in **cell adhesion** and is primarily expressed on endothelial cells. - Its role is more associated with **angiogenesis** and inflammation, lacking direct involvement in the fibrogenic process of cirrhosis. *IFN-y* - Interferon-gamma (**IFN-y**) is a cytokine that predominantly has a role in **immune modulation** and does not directly induce fibroblast activation. - It may have regulatory effects on inflammation but does not lead to significant fibrosis associated with liver cirrhosis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. With Illustrations By, pp. 31-32. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, pp. 830-832.

Q: What does Prussian blue staining specifically detect in histology?

Ferric iron. ***Ferric iron*** - The **Prussian blue reaction**, also known as Perls' stain, specifically identifies **ferric iron (Fe3+)** in tissue sections. - This stain is crucial for diagnosing conditions involving **iron overload**, such as hemochromatosis or hemosiderosis, by highlighting iron deposits as blue. *Ferrous iron* - The Prussian blue stain does **not react with ferrous iron (Fe2+)**; it specifically targets the ferric (oxidized) state of iron. - While ferrous iron is present in the body, it is not detected by this particular staining method for routine histological assessment of iron stores. *Glycogen* - **Glycogen** is a polysaccharide storage molecule and is typically stained using the **Periodic Acid-Schiff (PAS) stain**, which produces a magenta color. - Prussian blue staining is entirely unrelated to the detection of glycogen and would not highlight these molecules in tissue. *Lipids* - **Lipids** are fats and are typically stained with lipid-soluble dyes like **Oil Red O** or **Sudan Black**, especially in frozen sections to preserve their structure. - Prussian blue stain has no affinity for lipids and therefore cannot be used to detect them in histological samples.

Q: Sezary cells show which type of nucleus?

Cerebriform. ***Cerebriform*** - **Sezary cells** are characterized by their distinctive **cerebriform nuclei**, giving them an irregular, convoluted appearance [1,2]. - This finding is a hallmark of **cutaneous T-cell lymphoma** and emphasizes their potential malignancy [1,2]. *Round* - Round nuclei do not reflect the typical morphology of **Sezary cells**, which are noted for their **irregular shape**. - Other lymphocytes may exhibit round nuclei, but this does not specifically indicate a **Sezary cell** presence. *Pleomorphic* - While some malignant cells might show **pleomorphic nuclei**, Sezary cells uniquely showcase **cerebriform nuclei** rather than varying shapes [1,2]. - Pleomorphic is not a defining characteristic of **Sezary cells**, making this description inaccurate. *Eosinophillic* - Eosinophilic refers to cells that stain positively for **eosin**, typically associated with **eosinophils**, which is not relevant to **Sezary cells**. - Sezary cells are more about their **nuclear morphology** and less about eosinophilic staining characteristics. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 564-565. [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. 613-614.

Q: All of the following are features of granulomatous thyroiditis except?

Painless. ***Painless*** - Granulomatous thyroiditis is characterized by **painful** thyroid gland inflammation, which is a distinguishing feature. - Thus, describing it as **painless** contradicts the typical clinical presentation. *Hyperthyroidism* - Granulomatous thyroiditis may lead to **hyperthyroidism** initially due to the release of thyroid hormones from damaged follicles [1]. - However, this condition can also lead to transient thyroid function changes or even permanent hypothyroidism later on [1]. *Hypothyroidism* - While **hypothyroidism** can occur post-thyroiditis, it is not a feature of granulomatous thyroiditis at the outset like the **painless** descriptor. - This condition often starts with hyperthyroid symptoms and may evolve later, differing from primary hypothyroid disorders. *Giant cells on histology* - Histological examination typically reveals **multinucleated giant cells**, a hallmark of granulomatous inflammation, as seen in this thyroid condition. - This significant finding helps in differentiating it from other thyroid disorders. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1091-1092.

Q: Alkaline diuresis in drug poisoning is not done in?

Morphine. ***Morphine*** - **Morphine** is an **alkaline drug**, so its elimination is actually enhanced by **acidification of the urine**, not alkalinization. - Alkaline diuresis would decrease the ionization of morphine in the renal tubules, leading to **increased reabsorption** and reduced excretion. *Aspirin* - **Aspirin (acetylsalicylic acid)** is an **acidic drug**, and **alkaline diuresis** is effective in increasing its excretion by trapping the ionized form in the renal tubules. - This process prevents reabsorption and promotes clearance, which is a standard treatment for aspirin overdose. *Methotrexate* - **Methotrexate** is a **weak organic acid**, and **alkaline diuresis** is crucial in reducing its toxicity, especially in high-dose therapy. - By increasing urine pH, the renal elimination of methotrexate is significantly enhanced, preventing kidney damage and systemic accumulation. *Phenobarbitone* - **Phenobarbitone** is a **weak acid**, and **alkaline diuresis** is a well-established method to increase its renal excretion in cases of overdose. - Alkalinization of the urine promotes the ionization of phenobarbitone, reducing its reabsorption by the renal tubules and accelerating its elimination.

Q: Lysosome with undigested particle inside is known as?

Residual body. ***Residual body*** - A **residual body** is a lysosome that contains **undigested material** after the digestive process is complete. - These bodies can accumulate in cells over time and are sometimes associated with **cellular aging**. *Phagosome* - A **phagosome** is a vesicle formed around a particle engulfed by a cell through **phagocytosis**. - It has not yet fused with a lysosome, so digestion has not begun. *Phagolysosome* - A **phagolysosome** is formed when a **phagosome fuses with a lysosome**, initiating the process of digestion of the engulfed material. - At this stage, the contents are actively being broken down by lysosomal enzymes. *Autophagosome* - An **autophagosome** is a double-membraned vesicle that sequesters cellular components, such as damaged organelles or misfolded proteins, for degradation via **autophagy**. - It eventually fuses with a lysosome to form an autophagolysosome, but it is not itself a lysosome with undigested particles.

Q: Aortic valve closure corresponds to the beginning of which phase of the cardiac cycle?

Isovolumetric relaxation. ***Isovolumetric relaxation*** - **Aortic valve closure** marks the end of **ventricular ejection** and the beginning of **isovolumetric relaxation** as both the aortic and mitral valves are closed, and ventricular pressure drops without a change in volume. - This phase is vital for the heart to relax and prepare for filling, corresponding to the **second heart sound (S2)**. *Systole* - **Systole** refers to the **contraction phase** of the heart, encompassing both isovolumetric contraction and ventricular ejection. - Aortic valve closure signifies the end of the **ejection phase** of systole, not its beginning. *Parasystole* - **Parasystole** is an **arrhythmia** where an ectopic pacemaker competes with the normal sinus rhythm, leading to independent atrial or ventricular contractions. - It is a **pathological condition** and not a normal phase of the cardiac cycle. *Isovolumetric contraction* - **Isovolumetric contraction** occurs after the **mitral valve closes** and before the aortic valve opens, causing pressure to build in the ventricle. - This phase precedes **ventricular ejection** and is initiated by mitral valve closure, not aortic valve closure.

Question 1

Which gene is responsible for the production of COX type 3?

Accepted Answer

COX I gene

Answer

COX 3 gene

Answer

COX 2 gene

Answer

None of the above

Question 2

Which of the following is true regarding carcinoid tumor?

Accepted Answer

Neuroendocrine tumor

Answer

Associated with serotonin production

Answer

Potentially malignant tumor

Answer

Most common site is lung

Question 3

Which type of thyroid cancer is associated with primary hyperparathyroidism and phaeochromocytoma?

Accepted Answer

Medullary carcinoma of the thyroid

Answer

Papillary carcinoma of the thyroid

Answer

Anaplastic carcinoma of the thyroid

Answer

Follicular carcinoma of the thyroid

Question 4

Fibrosis associated with liver cirrhosis is mediated by -

Accepted Answer

Transforming Growth Factor-beta (TGF-β)

Answer

Platelet-Derived Growth Factor (PDGF)

Answer

Vascular Endothelial Growth Factor (VEGF)

Answer

Tumor Necrosis Factor-alpha (TNF-α)

Question 5

What does Prussian blue staining specifically detect in histology?

Accepted Answer

Ferric iron

Answer

Ferrous iron

Answer

Glycogen

Answer

Lipids

Question 6

Sezary cells show which type of nucleus?

Accepted Answer

Cerebriform

Answer

Pleomorphic

Answer

Round

Answer

Eosinophilic

Question 7

All of the following are features of granulomatous thyroiditis except?

Accepted Answer

Painless

Answer

Hyperthyroidism

Answer

Giant cells on histology

Answer

Hypothyroidism

Question 8

Alkaline diuresis in drug poisoning is not done in?

Accepted Answer

Morphine

Answer

Aspirin

Answer

Phenobarbitone

Answer

Methotrexate

Question 9

Lysosome with undigested particle inside is known as?

Accepted Answer

Residual body

Answer

Phagosome

Answer

Phagolysosome

Answer

Autophagosome

Question 10

Aortic valve closure corresponds to the beginning of which phase of the cardiac cycle?

Accepted Answer

Isovolumetric relaxation

Answer

Systole

Answer

Parasystole

Answer

Isovolumetric contraction

NEET-PG 2015

Biochemistry

Internal Medicine

Pathology

Pharmacology

Physiology