General Pathology Practice Questions

Q: Which of the following patterns is seen in DNA electrophoresis?

Apoptosis. **Explanation:** The correct answer is **Apoptosis**. The hallmark of apoptosis on DNA electrophoresis is a characteristic **"Step-ladder pattern."** **1. Why Apoptosis is correct:** During apoptosis, specific calcium- and magnesium-dependent endonucleases (caspase-activated DNase) cleave the DNA at internucleosomal linker regions [1]. Since DNA is wrapped around histones in regular intervals of approximately 180–200 base pairs, this enzymatic cleavage results in DNA fragments of varying lengths that are multiples of 180–200 bp. When these fragments are separated by electrophoresis, they form a distinct "step-ladder" appearance. **2. Why the other options are incorrect:** * **Necrosis:** Unlike the programmed cleavage in apoptosis, necrosis involves random, uncontrolled degradation of DNA and the nucleus (karyolysis). This results in a diffuse, continuous distribution of DNA fragments of all sizes, appearing as a **"Smear pattern"** on electrophoresis. * **Dysplasia and Metaplasia:** These are cellular adaptations or pre-neoplastic changes involving alterations in cell size, shape, organization, or phenotype. They do not involve the specific DNA fragmentation patterns seen in programmed cell death [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Apoptosis:** Step-ladder pattern (Internucleosomal cleavage). * **Necrosis:** Smear pattern (Random cleavage). * **Gold Standard for Apoptosis:** The **TUNEL assay** (Terminal deoxynucleotidyl transferase dUTP nick end labeling) is used to detect these DNA fragments in situ. * **Annexin V:** A marker used to detect phosphatidylserine on the outer leaflet of the plasma membrane, another early marker of 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. 63-65.

Question 1

Which of the following patterns is seen in DNA electrophoresis?

Accepted Answer

Apoptosis

Answer

Necrosis

Answer

Dysplasia

Answer

Metaplasia

Question 2

Which histopathological type of odontogenic keratocyst is commoner, more invasive, and has a greater tendency for recurrence?

Accepted Answer

Parakeratinised

Answer

Orthokeratinised

Answer

Non-keratinised

Answer

Diskeratinised

Question 3

Caseous necrosis is seen in which type of infection?

Accepted Answer

Treponemal infection

Answer

Cytomegalovirus (CMV) infection

Answer

Staphylococcal infection

Answer

Herpes Simplex Virus (HSV) infection

Question 4

All of the following are viral inclusion bodies, EXCEPT:

Accepted Answer

Psammoma bodies

Answer

Molluscum

Answer

Negri bodies

Answer

Bollinger bodies

Question 5

Which of the following is NOT an endogenous chemoattractant?

Accepted Answer

Integrins

Answer

C5a

Answer

LTB4

Answer

IL 8

Question 6

Which of the following is NOT responsible for the generation of Reactive Oxygen Species during Ischemia-Reperfusion Injury?

Accepted Answer

Activation of the complement system

Answer

Incomplete redox reactions by damaged mitochondria

Answer

Compromised cellular antioxidant defense mechanisms

Answer

Infiltrating leukocytes

Question 7

Myositis ossificans is an example of which of the following cellular adaptations?

Accepted Answer

Metaplasia

Answer

Hypertrophy

Answer

Hyperplasia

Answer

Both hyperplasia and hypertrophy

Question 8

Which of the following is NOT true about apoptosis?

Accepted Answer

Inflammation is present

Answer

Chromosomal breakage occurs

Answer

Clumping of chromatin is observed

Answer

Cell shrinkage is a characteristic feature

Question 9

A 52-year-old woman loses her right kidney following an automobile accident. A CT scan of the abdomen 2 years later shows marked enlargement of the left kidney. The renal enlargement is an example of which of the following adaptations?

Accepted Answer

Hypertrophy

Answer

Atrophy

Answer

Dysplasia

Answer

Hyperplasia

Question 10

Which protein does Cytochrome C interact with to initiate apoptosis?

Accepted Answer

Apaf-1

Answer

IL-10

Answer

Bcl-2

Answer

FADD

General Pathology — MCQs

General Pathology — MCQs

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