General Pathology Practice Questions

Q: Which amino acid is present in the active site of caspases?

Cysteine. **Explanation:** **Caspases** (Cysteine-aspartic proteases) are a family of protease enzymes that play an essential role in programmed cell death (apoptosis) [1]. The name "Caspase" is derived from its two primary functional characteristics: 1. **"C" (Cysteine):** The enzyme utilizes a **Cysteine** residue at its active site to perform the nucleophilic attack on the target protein. 2. **"Aspase" (Aspartic acid):** The enzyme cleaves its target proteins specifically at peptide bonds following an **Aspartic acid** residue. **Analysis of Options:** * **A. Cysteine (Correct):** As the catalytic nucleophile, the thiol (-SH) group of cysteine is indispensable for the proteolytic activity of all caspases. * **B. Cystine:** This is a dimeric amino acid formed by the oxidation of two cysteine residues (disulfide bond). It does not possess the free thiol group required for the catalytic mechanism. * **C. Methionine:** While it contains sulfur, it is non-polar and lacks the reactive thiol group necessary for the active site of these proteases. * **D. Taurine:** This is an amino sulfonic acid, not a proteinogenic amino acid, and is not involved in the catalytic site of caspases. **High-Yield Clinical Pearls for NEET-PG:** * **Initiator Caspases:** Caspase 8 and 9 (and 10) [1]. * **Executioner Caspases:** Caspase 3, 6, and 7 (Caspase 3 is the most common). * **Inflammatory Caspase:** Caspase 1 (involved in the formation of the inflammasome and processing of IL-1β). * **Marker of Apoptosis:** The presence of cleaved (active) caspase-3 is a definitive histological marker for cells undergoing apoptosis [1]. **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, pp. 64-71.

Q: Which of the following intermediate filaments is typically found in connective tissue?

Vimentin. **Explanation:** Intermediate filaments are critical components of the cytoskeleton that provide mechanical strength to cells [1]. Their distribution is highly tissue-specific, making them excellent immunohistochemical (IHC) markers in pathology [1]. **Why Vimentin is Correct:** **Vimentin** is the characteristic intermediate filament of **mesenchymal cells**. Since connective tissue (including fibroblasts, osteoblasts, and chondrocytes), endothelium, and smooth muscle are derived from the mesenchyme, Vimentin is the primary marker for these tissues [1]. In clinical practice, Vimentin positivity is used to identify sarcomas. **Analysis of Incorrect Options:** * **Keratin (Cytokeratin):** Found in **epithelial cells** [1]. It is the hallmark marker for carcinomas. * **Desmin:** Found in **muscle cells** (skeletal, cardiac, and smooth muscle). It links myofibrils to the sarcolemma. * **Lamin:** Found in the **nuclear envelope** (nuclear lamina) of almost all eukaryotic cells, not specifically in the connective tissue cytoplasm. **High-Yield Clinical Pearls for NEET-PG:** * **GFAP (Glial Fibrillary Acidic Protein):** The intermediate filament marker for Astrocytes (Glial cells). * **Neurofilaments:** Found in Axons of neurons. * **Peripherin:** Found in Peripheral nervous system neurons. * **IHC Shortcut:** If a tumor is **Vimentin (+)**, think Sarcoma; if **Cytokeratin (+)**, think Carcinoma; if **Desmin (+)**, think Rhabdomyosarcoma/Leiomyosarcoma.

Question 1

An 85-year-old man falls in the bathtub and strikes the back of his head. Over the next 24 hours, he becomes increasingly somnolent. A head CT scan shows an accumulation of fluid beneath the dura, compressing the left cerebral hemisphere. Which of the following terms best describes this collection of fluid?

Accepted Answer

Hematoma

Answer

Congestion

Answer

Ecchymosis

Answer

Petechiae

Question 2

In Vitamin-A deficiency, cancerous lesions occur due to which cellular adaptation?

Accepted Answer

Metaplasia

Answer

Dysplasia

Answer

Aplasia

Answer

Hyperplasia

Question 3

In individuals who donate one lobe of the liver for transplantation, the remaining organ soon grows back to its original size. This is an example of which adaptive mechanism?

Accepted Answer

Hyperplasia

Answer

Hypertrophy

Answer

Atrophy

Answer

Metaplasia

Question 4

A 59-year-old man experiences acute chest pain and is rushed to the emergency room. Laboratory studies and ECG demonstrate an acute myocardial infarction; however, coronary artery angiography performed 2 hours later does not show evidence of thrombosis. Intravascular thrombolysis that occurred in this patient was mediated by plasminogen activators that were released by which of the following cells?

Accepted Answer

Endothelial cells

Answer

Cardiac myocytes

Answer

Macrophages

Answer

Segmented neutrophils

Question 5

Which of the following diseases demonstrates monogenic inheritance?

Accepted Answer

Hereditary spherocytosis

Answer

Atherosclerosis

Answer

Hypertension

Answer

Coronary disorder

Question 6

Which amino acid is present in the active site of caspases?

Accepted Answer

Cysteine

Answer

Cystine

Answer

Methionine

Answer

Taurine

Question 7

How can a surgeon confirm intraoperatively that a resected margin of tissue does not contain suspicious tissue?

Accepted Answer

Frozen section

Answer

Punch biopsy

Answer

Brush biopsy

Answer

Exfoliative cytology

Question 8

Which of the following is not a protein misfolding disorder?

Accepted Answer

Tuberculosis

Answer

Creutzfeldt Jakob disease

Answer

Alzheimer's disease

Answer

Cystic fibrosis

Question 9

Which of the following intermediate filaments is typically found in connective tissue?

Accepted Answer

Vimentin

Answer

Keratin

Answer

Desmin

Answer

Lamin

Question 10

Apoptosis is associated with all the following features EXCEPT?

Accepted Answer

Inflammation

Answer

Cell shrinkage

Answer

Intact cellular contents

Answer

Nucleosome size fragmentation of nucleus

General Pathology — MCQs

General Pathology — MCQs

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