General Pathology Practice Questions

Q: Which organelle plays a pivotal role in apoptosis?

Mitochondria. **Explanation:** The **Mitochondrion** is the central executioner of the intrinsic (mitochondrial) pathway of apoptosis. This process is initiated in response to internal cellular stress, such as DNA damage or oxidative stress. The key event is the increase in **Mitochondrial Outer Membrane Permeability (MOMP)**, regulated by the Bcl-2 family of proteins. Pro-apoptotic proteins (Bax/Bak) create pores in the membrane, leading to the leakage of **Cytochrome c** into the cytoplasm. Once released, Cytochrome c binds with Apaf-1 to form the **apoptosome**, which activates Caspase-9, triggering the executioner caspase cascade. **Analysis of Incorrect Options:** * **A. Cytoplasm:** While the later stages of apoptosis (caspase activation) occur here, the cytoplasm serves as the medium rather than the regulatory "pivotal" organelle. * **B. Golgi Complex:** Primarily involved in protein modification, sorting, and packaging; it does not play a primary role in initiating or regulating programmed cell death. * **C. Nucleus:** Although nuclear changes (chromatin condensation and DNA fragmentation by CAD—Caspase Activated DNase) are hallmarks of apoptosis, they are downstream effects rather than the initiating trigger. **NEET-PG High-Yield Pearls:** * **Anti-apoptotic proteins:** Bcl-2, Bcl-xL (they stabilize the mitochondrial membrane). * **Pro-apoptotic proteins:** Bax, Bak, Bim, Bad, PUMA. * **Mitochondrial markers:** Cytochrome c release is the definitive sign of the intrinsic pathway. * **Extrinsic Pathway:** Initiated by Death Receptors (e.g., Fas, TNF-R) and involves **Caspase-8**.

Q: The given pattern of electrophoresis is obtained in which of the following conditions?

Apoptosis. ***Apoptosis*** - **Internucleosomal DNA cleavage** by **endonucleases** produces fragments of approximately **180-200 bp multiples**, creating the characteristic **DNA ladder pattern** on gel electrophoresis. - This orderly fragmentation occurs due to **chromatin condensation** and systematic DNA breakdown by **caspase-activated DNase (CAD)**. *Necrosis* - Results in **random DNA degradation** causing a **smear pattern** rather than distinct bands on electrophoresis. - **Lysosomal enzymes** and **external factors** cause chaotic cellular breakdown without the organized DNA fragmentation seen in apoptosis. *Necroptosis* - A form of **programmed necrosis** that produces **random DNA fragmentation** similar to classical necrosis, resulting in a **smear pattern**. - Despite being programmed, it lacks the **caspase-mediated** organized DNA cleavage characteristic of apoptosis. *Free radical injury* - **Oxidative stress** causes **random DNA strand breaks** and base modifications, producing a **smear pattern** on electrophoresis. - **Hydroxyl radicals** and other **reactive oxygen species** damage DNA non-specifically without creating the systematic fragmentation of apoptosis.

Q: Hypercoagulability due to a defective Factor V gene is called?

Leiden mutation. **Explanation:** **Factor V Leiden mutation** is the most common inherited cause of hypercoagulability (thrombophilia) among Caucasians [1]. It involves a specific point mutation in the Factor V gene where **Arginine is replaced by Glutamine at position 506**. Normally, **Activated Protein C (APC)** inactivates Factor Va to prevent excessive clotting. However, the Leiden mutation alters the cleavage site, making Factor Va resistant to inactivation by APC [2]. This "APC resistance" leads to a prothrombotic state, significantly increasing the risk of Deep Vein Thrombosis (DVT) and pulmonary embolism [1]. **Analysis of Incorrect Options:** * **Lisbon mutation:** This is a distractor and is not a recognized clinical term for a hypercoagulable state. * **Antiphospholipid syndrome (APS):** This is an *acquired* autoimmune hypercoagulable state characterized by antibodies (like Lupus anticoagulant) against phospholipid-binding proteins [2]. It is not caused by a Factor V gene defect. * **Inducible thrombocytopenia syndrome:** Likely refers to Heparin-Induced Thrombocytopenia (HIT), an immune-mediated drug reaction causing low platelets and paradoxical thrombosis, rather than a primary genetic defect. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** Autosomal Dominant. * **Gold Standard Test:** DNA analysis for the F5 gene mutation [2]. * **Screening Test:** Activated Protein C resistance (APCR) test [2]. * **Association:** It is a major risk factor for cerebral venous sinus thrombosis (CVST) in young patients, especially those on oral contraceptives [1].

Q: Malarial pigment is formed by?

Hemoglobin. **Explanation:** The correct answer is **Hemoglobin**. **Why Hemoglobin is correct:** Malarial pigment, also known as **hemozoin**, is a dark brown, granular byproduct of the digestion of host erythrocytes by *Plasmodium* parasites. Within the red blood cell, the parasite consumes host **hemoglobin** to obtain essential amino acids. However, this process releases free **heme**, which is toxic to the parasite. To detoxify it, the parasite polymerizes the reactive heme into an insoluble, non-toxic crystalline form called hemozoin. This pigment is a hallmark of malarial infection and is visible under light microscopy within the parasite's food vacuole. **Why other options are incorrect:** * **Parasite:** While the parasite *creates* the pigment, the pigment itself is chemically derived from the host's hemoglobin, not the parasite's own cellular structures. * **Bilirubin:** Bilirubin is a breakdown product of heme metabolism in the human liver/spleen. While malaria causes hemolysis leading to indirect hyperbilirubinemia (jaundice), it is not the constituent of the malarial pigment found inside the RBC. **High-Yield Clinical Pearls for NEET-PG:** * **Schüffner’s dots:** These are different from malarial pigment; they are morphological changes (stippling) in the RBC membrane seen specifically in *P. vivax* and *P. ovale*. * **Detection:** Hemozoin is birefringent under polarized light. * **Drug Mechanism:** Chloroquine works by inhibiting the biocrystallization of heme into hemozoin, leading to a buildup of toxic heme that kills the parasite. * **Phagocytosis:** After the RBC ruptures, malarial pigment is taken up by monocytes and macrophages (reticuloendothelial system), often leading to a slate-grey discoloration of the spleen and liver in chronic cases.

Question 1

A patient with XO chromosomes and short stature is likely to have which of the following conditions?

Accepted Answer

Turner's syndrome

Answer

Klinefelter's syndrome

Answer

Condy syndrome

Answer

Condy phenomenon

Question 2

Metaplasia is thought to be caused in most cases by:

Accepted Answer

Chronic irritation

Answer

Genetic mutation

Answer

Oncogenic virus

Answer

Immunologic reaction

Question 3

Which organelle plays a pivotal role in apoptosis?

Accepted Answer

Mitochondria

Answer

Cytoplasm

Answer

Golgi complex

Answer

Nucleus

Question 4

The given pattern of electrophoresis is obtained in which of the following conditions?

Accepted Answer

Apoptosis

Answer

Necrosis

Answer

Necroptosis

Answer

Free radical injury

Question 5

Hypercoagulability due to a defective Factor V gene is called?

Accepted Answer

Leiden mutation

Answer

Lisbon mutation

Answer

Antiphospholipid syndrome

Answer

Inducible thrombocytopenia syndrome

Question 6

Which of the following is an inhibitor of apoptosis?

Accepted Answer

Bcl-2

Answer

Bad

Answer

Bax

Answer

All of the above

Question 7

What is the most common primary immunodeficiency?

Accepted Answer

Isolated IgA immunodeficiency

Answer

Common variable immunodeficiency

Answer

Wiskott-Aldrich syndrome

Answer

Acquired immunodeficiency syndrome

Question 8

Petechiae in scurvy is due to which of the following?

Accepted Answer

Endothelial disintegration

Answer

Platelet dysfunction

Answer

Thrombocytopenia

Answer

Clotting factor deficiency

Question 9

Malarial pigment is formed by?

Accepted Answer

Hemoglobin

Answer

Parasite

Answer

Bilirubin

Answer

Any of the above

Question 10

Which of the following statements regarding lipofuscin is not true?

Accepted Answer

It results in excessive lipid accumulation in the circulation

Answer

Perinuclear location

Answer

It is yellow-brown in color

Answer

Has a role in lipid peroxidation

General Pathology — MCQs

General Pathology — MCQs

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