NEET-PG 2022 Practice Questions

Q: Cancer cells preferentially utilize glycolysis for energy production even in the presence of adequate oxygen. What is this phenomenon called?

Warburg effect. ***Warburg*** - The **Warburg effect** describes how cancer cells preferentially use glycolysis for energy production even in the presence of oxygen, allowing them to thrive in **hypoxic conditions** [1]. - This metabolic adaptation supports **cell proliferation** and survival in tumor microenvironments where oxygen is limited [1][3]. - Cancer cells upregulate glucose uptake and express specific metabolic enzymes like the M2 isoform of pyruvate kinase that facilitate this altered metabolism [2][4]. *Wanton* - This term typically refers to recklessness or extravagance and is not used in the context of cancer metabolism or hypoxia. - There are no associations with **cancer cell adaptation** under adverse environmental conditions. *Wormian* - **Wormian bones** are extra bone pieces within sutures of the skull, unrelated to cancer cell metabolism or survival mechanisms. - This term does not connect to **hypoxia** or metabolic adaptations in cancer biology. *Wolf* - "Wolf" has no recognized connection to cancer cell biology, particularly regarding metabolic adaptations under **hypoxic stress**. - It does not imply any concept associated with how cancer cells cope with adverse conditions. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 307-308. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 308-310. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 290-291. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. With Illustrations By, pp. 26-27.

Q: A patient with hemolytic anemia has a defect in the enzyme glucose-6-phosphate dehydrogenase. Which of the following pathways is directly affected by this defect?

Pentose phosphate pathway. ***Pentose phosphate pathway*** - **Glucose-6-phosphate dehydrogenase (G6PD)** is the **rate-limiting enzyme** in the **pentose phosphate pathway (PPP)**, initiating the oxidative phase. - Deficiency in G6PD impairs the production of **NADPH**, which is crucial for reducing **oxidative stress** in red blood cells. *Glycolysis* - This pathway metabolizes glucose to pyruvate for **ATP production** and does not directly involve G6PD. - While G6P is an intermediate in both pathways, its conversion in glycolysis is catalyzed by phosphoglucose isomerase, not G6PD. *TCA cycle* - The **tricarboxylic acid (TCA) cycle** is a central metabolic pathway for energy production occurring in the **mitochondria**. - It involves the oxidation of acetyl-CoA and does not directly utilize G6PD. *Urea cycle* - The **urea cycle** is responsible for detoxifying ammonia by converting it into urea, primarily occurring in the **liver**. - This pathway is unrelated to glucose metabolism or G6PD activity.

Q: A patient is diagnosed with scurvy. This condition is due to a deficiency in which vitamin?

Vitamin C. ***Vitamin C*** - **Scurvy** is directly caused by a prolonged and severe deficiency of **Vitamin C (ascorbic acid)**. - Vitamin C is essential for **collagen synthesis**, and its deficiency leads to impaired wound healing, fragile blood vessels, and gum disease, which are hallmarks of scurvy. *Vitamin A* - Deficiency in Vitamin A primarily causes **vision problems**, such as night blindness, and can lead to xerophthalmia, but not scurvy. - It plays a crucial role in **immune function** and cell growth, distinguishing its role from collagen synthesis. *Vitamin D* - A deficiency in Vitamin D is associated with **rickets** in children and **osteomalacia** in adults, conditions primarily affecting bone mineralization. - It is vital for **calcium and phosphate absorption**, which is unrelated to the collagen defects seen in scurvy. *Vitamin E* - Deficiency in Vitamin E is rare and can lead to **neurological symptoms** like ataxia and peripheral neuropathy. - It acts as a **powerful antioxidant**, protecting cells from oxidative damage, which is a different metabolic pathway than Vitamin C's role in collagen.

Q: Which of the following is the MOST common complication of untreated hypertension?

Stroke. ***Stroke*** - **Untreated hypertension** is a major risk factor for both **ischemic** and **hemorrhagic strokes**, damaging blood vessels in the brain [1]. - Sustained high blood pressure can lead to **atherosclerosis** and weakened blood vessel walls, increasing the likelihood of a stroke [1]. *Heart failure* - While hypertension is a leading cause of **heart failure**, it typically develops over a longer period as the heart works harder against elevated pressure, leading to remodeling and dysfunction [2]. - In terms of acute, severe complications, a stroke is often considered more immediately catastrophic. *Kidney damage* - **Hypertensive nephropathy** is a significant long-term complication where high blood pressure damages the small blood vessels in the kidneys, impairing their function. - This process is gradual and contributes to **chronic kidney disease**, but stroke often emerges as a more common and acute serious event. *Vision loss* - **Hypertensive retinopathy** involves damage to the blood vessels in the retina, which can lead to vision problems including **vision loss** or **blindness**. - This is a serious complication, but **stroke** generally has a higher prevalence and more immediate impact in terms of overall morbidity and mortality associated with untreated hypertension.

Q: What is the initial treatment for most patients with growth hormone-secreting pituitary adenoma?

Transphenoidal surgical resection. ***Transphenoidal surgical resection*** - This is the **preferred initial treatment** for most growth hormone (GH)-secreting pituitary adenomas, as it offers the best chance for **cure** and rapid reduction in GH levels [1]. - Success rates are high, especially for **smaller tumors** (microadenomas), and it can quickly relieve mass effect symptoms [1]. *Somatostatin analogs* - These are typically used as **second-line therapy** if surgery is unsuccessful or contraindicated, or in patients not surgical candidates. - They work by **inhibiting GH secretion** but do not usually achieve a complete cure like surgery. *GH receptor antagonists* - These medications, such as pegvisomant, **block the action of GH** at its receptor, normalizing IGF-1 levels. - They are primarily used when other treatments, including surgery and somatostatin analogs, have failed to control GH excess. *Dopamine agonists* - While dopamine agonists (e.g., cabergoline) can **sometimes reduce GH secretion** in a minority of patients, they are significantly less effective for GH-secreting tumors compared to prolactinomas [1]. - They are occasionally used as **adjunctive therapy** or in specific cases where the GH-secreting tumor also co-secretes prolactin [1].

Q: A 40-year-old woman with rheumatoid arthritis presents with eye pain and redness. Examination reveals scleritis. What is the most likely associated systemic complication?

Interstitial lung disease. ***Interstitial lung disease*** - **Scleritis** in a patient with **rheumatoid arthritis** often indicates a more severe, systemic form of the disease. - **Interstitial lung disease (ILD)** is a common and serious **extra-articular manifestation** of rheumatoid arthritis, associated with higher disease activity and worse prognosis. *Cardiomyopathy* - While cardiac involvement can occur in RA (e.g., pericarditis, myocarditis), **cardiomyopathy** is less directly correlated with scleritis as a linked severe systemic complication. - **Rheumatoid arthritis** can increase the risk of cardiovascular disease due to accelerated atherosclerosis and systemic inflammation, but cardiomyopathy itself is not typically the direct systemic complication associated with scleritis. *Renal failure* - **Renal involvement** in rheumatoid arthritis is uncommon, usually related to complications from treatment (e.g., NSAID-induced nephropathy) or secondary amyloidosis, not directly with scleritis. - Scleritis itself does not directly predispose to **renal failure** as a primary systemic complication of RA. *Peripheral neuropathy* - **Peripheral neuropathy** can be a complication of rheumatoid arthritis, particularly in severe cases or vasculitis. - However, it is not as strongly or directly linked to the presence of **scleritis** as **interstitial lung disease** is, in terms of signifying systemic disease severity.

Q: A 45-year-old patient with a history of poorly controlled diabetes presents with sinus pain, nasal discharge, and facial swelling. A biopsy reveals broad, nonseptate hyphae branching at wide angles. What is the most likely causative agent?

Rhizopus spp.. ***Rhizopus spp.*** - The patient's presentation with **sinus pain**, **nasal discharge**, **facial swelling**, and a history of **poorly controlled diabetes** is classic for **mucormycosis** (also known as zygomycosis). - **Biopsy findings** of **broad, nonseptate hyphae branching at wide/irregular angles** are pathognomonic for mucormycosis, most commonly caused by *Rhizopus* species. - Diabetes mellitus, particularly when poorly controlled with **ketoacidosis**, is a major risk factor for rhinocerebral mucormycosis. *Aspergillus fumigatus* - This fungus typically causes infections with **septate hyphae** that **branch at acute angles** (45 degrees), which is morphologically distinct from mucormycosis. - While *Aspergillus* can cause invasive sinusitis in immunocompromised patients, the specific hyphal morphology (nonseptate, wide-angle branching) points away from it. *Candida albicans* - *Candida albicans* is a yeast that typically appears as **oval budding cells** and **pseudohyphae** on microscopy, not broad, nonseptate hyphae. - While it can cause opportunistic infections in diabetic and immunocompromised patients, its microscopic appearance is entirely inconsistent with the biopsy findings. *Cryptococcus neoformans* - *Cryptococcus neoformans* is an **encapsulated yeast** that is typically identified by its **spherical or oval budding cells** with a characteristic **polysaccharide capsule** visible with India ink stain. - It primarily causes **meningitis** and pulmonary infections in immunocompromised hosts, and its morphology (yeast, not hyphae) is entirely different from the described findings.

Q: A 55-year-old woman is undergoing chemotherapy for breast cancer and experiences severe nausea and vomiting. Which antiemetic, recognized for its minimal extrapyramidal side effects, would be appropriate for her condition?

Ondansetron. ***Ondansetron*** - **Ondansetron** is a 5-HT3 receptor antagonist, highly effective against chemotherapy-induced nausea and vomiting (CINV) due to its action on serotonin receptors in the **chemoreceptor trigger zone** and **gastrointestinal tract**. - It is known for its favorable side effect profile, with **minimal to no extrapyramidal symptoms**, making it a preferred choice in patients where such effects are a concern. *Metoclopramide* - While effective against nausea and vomiting, **metoclopramide** (a D2 receptor antagonist) can cause **extrapyramidal symptoms** such as **dystonia** and **tardive dyskinesia**, especially with prolonged use or higher doses. - Its mechanism of action includes both prokinetic effects and central antiemetic action, but its side effect profile makes it less ideal when avoiding extrapyramidal symptoms is a priority. *Promethazine* - **Promethazine** is a first-generation antihistamine with antiemetic properties, but it can cause significant **sedation** and has some **anticholinergic side effects**. - Although its extrapyramidal risk is lower than some other drugs, it's not the primary choice for chemotherapy-induced nausea due to its sedative effects and generally less potent antiemetic action for CINV compared to 5-HT3 antagonists. *Prochlorperazine* - **Prochlorperazine** is a phenothiazine antipsychotic with strong antiemetic effects, acting primarily as a **dopamine receptor antagonist**. - It carries a significant risk of **extrapyramidal side effects**, including **acute dystonia** and **parkinsonism**, making it less suitable when such side effects must be strictly avoided.

Q: Which of the following statements about the O2-Hb dissociation curve is correct?

It demonstrates cooperative binding.. ***It demonstrates cooperative binding.*** - **Cooperative binding** describes how the binding of one oxygen molecule to hemoglobin increases the affinity of the remaining binding sites for oxygen. - This property gives the O2-Hb dissociation curve its characteristic **sigmoid (S-shaped)** appearance, allowing for efficient oxygen loading in the lungs and unloading in the tissues. *The curve is a straight line.* - The O2-Hb dissociation curve is **sigmoid or S-shaped**, not a straight line, due to the phenomenon of cooperative binding. - A straight line would imply a constant affinity of hemoglobin for oxygen, which is not the case. *It is 100% saturated at a PO2 of 100 mmHg.* - Hemoglobin is typically around **97-98% saturated** at a PO2 of 100 mmHg (arterial blood). - Complete 100% saturation is rarely achieved under physiological conditions. *A hemoglobin molecule can carry 4 molecules of O2.* - While this statement is factually true (one hemoglobin molecule has **four heme groups** and can bind up to **four molecules of oxygen**), it describes the structure and oxygen-carrying capacity of hemoglobin rather than a characteristic of the dissociation **curve itself**. - The question asks about features of the O2-Hb dissociation curve, and cooperative binding is the key property that defines the curve's behavior and sigmoid shape.

Question 1

Cancer cells preferentially utilize glycolysis for energy production even in the presence of adequate oxygen. What is this phenomenon called?

Accepted Answer

Warburg effect

Answer

Hypoxic adaptation

Answer

Anoxic survival

Answer

Oxygen-independent metabolism

Question 2

A patient with hemolytic anemia has a defect in the enzyme glucose-6-phosphate dehydrogenase. Which of the following pathways is directly affected by this defect?

Accepted Answer

Pentose phosphate pathway

Answer

Glycolysis

Answer

TCA cycle

Answer

Urea cycle

Question 3

A patient is diagnosed with scurvy. This condition is due to a deficiency in which vitamin?

Accepted Answer

Vitamin C

Answer

Vitamin A

Answer

Vitamin D

Answer

Vitamin E

Question 4

Which of the following is the MOST common complication of untreated hypertension?

Accepted Answer

Stroke

Answer

Kidney damage

Answer

Heart failure

Answer

Vision loss

Question 5

What is the initial treatment for most patients with growth hormone-secreting pituitary adenoma?

Accepted Answer

Transphenoidal surgical resection

Answer

Somatostatin analogs

Answer

Dopamine agonists

Answer

GH receptor antagonists

Question 6

A 40-year-old woman with rheumatoid arthritis presents with eye pain and redness. Examination reveals scleritis. What is the most likely associated systemic complication?

Accepted Answer

Interstitial lung disease

Answer

Cardiomyopathy

Answer

Renal failure

Answer

Peripheral neuropathy

Question 7

A 45-year-old patient with a history of poorly controlled diabetes presents with sinus pain, nasal discharge, and facial swelling. A biopsy reveals broad, nonseptate hyphae branching at wide angles. What is the most likely causative agent?

Accepted Answer

Rhizopus spp.

Answer

Aspergillus fumigatus

Answer

Candida albicans

Answer

Cryptococcus neoformans

Question 8

A 55-year-old woman is undergoing chemotherapy for breast cancer and experiences severe nausea and vomiting. Which antiemetic, recognized for its minimal extrapyramidal side effects, would be appropriate for her condition?

Accepted Answer

Ondansetron

Answer

Metoclopramide

Answer

Promethazine

Answer

Prochlorperazine

Question 9

Which of the following statements about the O2-Hb dissociation curve is correct?

Accepted Answer

It demonstrates cooperative binding.

Answer

The curve is a straight line.

Answer

It is 100% saturated at a PO2 of 100 mmHg.

Answer

A hemoglobin molecule can carry 4 molecules of O2.

Question 10

A 60-year-old male with a history of smoking presents with severe abdominal pain and a pulsatile abdominal mass. What is the most appropriate next step in managing this patient?

Accepted Answer

CT angiography

Answer

Immediate surgery

Answer

Ultrasound of the abdomen

Answer

Observation

NEET-PG 2022

Biochemistry

Internal Medicine

Microbiology

Pharmacology

Physiology

Surgery