General Pathology Practice Questions

Q: In-situ DNA nick end labeling can quantitate what fraction of cells?

Cells in apoptotic pathways. **Explanation:** **TUNEL (Terminal deoxynucleotidyl transferase dUTP Nick End Labeling)** is a specialized laboratory technique used to detect and quantitate cells undergoing **apoptosis**. **Why Option A is Correct:** A hallmark of apoptosis is the activation of endogenous endonucleases (caspase-activated DNase), which cleave genomic DNA into fragments of 180–200 base pairs (creating the characteristic "DNA laddering" on electrophoresis). These breaks result in numerous exposed **3'-hydroxyl (3'-OH) ends** or "nicks." The TUNEL assay uses the enzyme **Terminal deoxynucleotidyl transferase (TdT)** to attach labeled nucleotides (like dUTP) to these 3'-OH ends. The intensity of the labeling is proportional to the degree of DNA fragmentation, allowing for the quantification of apoptotic cells. **Why Other Options are Incorrect:** * **Option B (Cells in S phase):** These are typically identified using **BrdU (Bromodeoxyuridine)** labeling or Ki-67 protein expression, which mark DNA synthesis and active proliferation. * **Option C (p53 gene product):** p53 is a tumor suppressor protein detected via **Immunohistochemistry (IHC)**. While p53 can trigger apoptosis, TUNEL measures the resulting DNA damage, not the protein itself. * **Option D (bcr/abl gene):** This fusion gene (Philadelphia chromosome) is detected using **FISH (Fluorescence In Situ Hybridization)** or **RT-PCR**, not by end-labeling DNA nicks. **High-Yield Clinical Pearls for NEET-PG:** * **DNA Laddering:** A specific feature of apoptosis (not necrosis) seen on agar gel electrophoresis. * **Annexin V:** Another marker for apoptosis; it binds to **Phosphatidylserine**, which flips from the inner to the outer leaflet of the plasma membrane during early apoptosis. * **Caspase-3:** The most common "executioner" caspase involved in both intrinsic and extrinsic pathways.

Q: Trauma to the breast causes which type of necrosis?

Fat necrosis. **Explanation:** **Fat necrosis** is the correct answer because it is a specialized form of cell death occurring in tissues with high lipid content, such as the breast, omentum, and pancreas [1]. When trauma occurs to the breast, adipocytes (fat cells) rupture, releasing neutral fats (triglycerides). These fats are broken down by lipases into free fatty acids, which then combine with calcium ions in a process called **saponification** [1]. This results in the characteristic "chalky white" macroscopic appearance [1]. **Analysis of Incorrect Options:** * **Coagulative Necrosis:** This is the most common pattern of necrosis, typically caused by ischemia/infarction in solid organs (e.g., heart, kidney, spleen), except the brain. The cell architecture is preserved for a few days. * **Liquefactive Necrosis:** Characterized by the digestion of dead cells into a liquid viscous mass. It is seen in focal bacterial/fungal infections (abscesses) and **hypoxic death of cells within the Central Nervous System (brain).** * **Caseous Necrosis:** A "cheese-like" friable appearance characteristic of **Tuberculosis** infection [1]. It is a combination of coagulative and liquefactive necrosis where the tissue architecture is completely obliterated. **High-Yield Pearls for NEET-PG:** * **Clinical Mimicry:** Breast fat necrosis is high-yield because it can present as a painless, hard mass with skin retraction, clinically **mimicking breast carcinoma**. * **Radiology:** On mammography, it may show "egg-shell" calcifications. * **Enzymatic vs. Traumatic:** Fat necrosis in the **pancreas** is "enzymatic" (due to activated lipases), whereas in the **breast**, it is typically "traumatic." **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, p. 55.

Question 1

What does not occur in lysosomal storage disorders?

Accepted Answer

Lysis of the cell

Answer

Increased number and size of lysosomes

Answer

Apoptosis of the cell

Answer

Accumulation of polyubiquitinated proteins

Question 2

In-situ DNA nick end labeling can quantitate what fraction of cells?

Accepted Answer

Cells in apoptotic pathways

Answer

Cells in S phase

Answer

p53 gene product

Answer

bcr/abl gene

Question 3

Which of the following statements is NOT true about cutaneous calciphylaxis?

Accepted Answer

It exemplifies dystrophic calcification.

Answer

It is a potentially lethal condition.

Answer

It is characterized by progressive cutaneous vascular calcification.

Answer

It is seen in patients with chronic renal failure who have increased calcium, phosphate, and parathormone levels.

Question 4

A pregnant uterus is an example of which of the following cellular adaptations?

Accepted Answer

Hypertrophy

Answer

Metaplasia

Answer

Dysplasia

Answer

Atrophy

Question 5

What is true about mural thrombi?

Accepted Answer

Occur in large vessels such as the heart and aorta

Answer

Common in small blood vessels of the heart

Answer

Appear dark red in color

Answer

Are commonly seen in the lungs

Question 6

What is the most common cause of systemic thromboembolism?

Accepted Answer

Intracardiac mural thrombi

Answer

Paradoxical emboli

Answer

Aortic aneurysms

Answer

Unknown origin

Question 7

Trauma to the breast causes which type of necrosis?

Accepted Answer

Fat necrosis

Answer

Coagulative necrosis

Answer

Liquefactive necrosis

Answer

Caseous necrosis

Question 8

What type of necrosis is typically seen in nervous tissue?

Accepted Answer

Liquefactive

Answer

Coagulative

Answer

Caseous

Answer

Fibrinoid

Question 9

Which of the following is not seen in apoptosis?

Accepted Answer

Inflammation

Answer

Nuclear fragmentation

Answer

Cellular shrinkage

Answer

Alteration in cellular membrane structure

Question 10

Which of the following does not lead to increased formation of thrombus?

Accepted Answer

Hyperglycemia

Answer

Malignancy

Answer

Decreased blood volume

Answer

Decreased blood flow

General Pathology — MCQs

General Pathology — MCQs

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