General Pathology Practice Questions

Q: CD-95 is a marker of which of the following?

Death receptor. **Explanation:** **CD95**, also known as **Fas receptor**, is a critical cell surface marker that belongs to the Tumor Necrosis Factor Receptor (TNFR) superfamily [1]. It is the primary mediator of the **Extrinsic Pathway of Apoptosis** [1]. 1. **Why Option A is Correct:** When the Fas receptor (CD95) binds to its specific ligand, **FasL (CD95L)**, it undergoes trimerization [1]. This leads to the recruitment of the adapter protein **FADD** (Fas-associated death domain), forming the **DISC** (Death-Inducing Signaling Complex) [1]. This complex activates **Caspase-8** (or Caspase-10), which directly triggers the executioner caspases, leading to programmed cell death [1]. Thus, CD95 is a classic "Death Receptor." 2. **Why Other Options are Incorrect:** * **MHC Complex:** MHC molecules (HLA) are involved in antigen presentation, not direct apoptosis signaling. * **T helper cells:** The primary marker for T-helper cells is **CD4**. While activated T-cells may express FasL, CD95 itself is the receptor found on target cells. * **NK cells:** The characteristic markers for NK cells are **CD16** and **CD56**. **High-Yield Clinical Pearls for NEET-PG:** * **ALPS (Autoimmune Lymphoproliferative Syndrome):** Caused by mutations in the Fas receptor (CD95), Fas ligand, or Caspase-8/10. It presents with lymphadenopathy, splenomegaly, and autoimmunity due to the failure of self-reactive lymphocytes to undergo apoptosis. * **Caspase Cascade:** Remember that the Extrinsic pathway (CD95) uses **Caspase-8**, while the Intrinsic (Mitochondrial) pathway uses **Caspase-9** [1]. * **FLIP:** A protein that inhibits apoptosis by blocking the activation of Caspase-8. **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. 64-67.

Q: What is Trisomy 21?

Down's syndrome. **Explanation:** **Trisomy 21** refers to the presence of an extra copy of chromosome 21, resulting in a total of 47 chromosomes [1]. This is the genetic basis for **Down’s syndrome**, the most common chromosomal disorder and a frequent cause of intellectual disability [1]. In 95% of cases, it occurs due to **meiotic non-disjunction**, which is strongly associated with advanced maternal age. **Analysis of Options:** * **Option A (Correct):** Down’s syndrome is synonymous with Trisomy 21 [1]. * **Option B (Incorrect):** **Turner syndrome** is a monosomy (45, XO), characterized by the absence of one X chromosome in females. * **Option C (Incorrect):** **Klinefelter syndrome** involves an extra X chromosome in males (47, XXY). * **Option D (Incorrect):** **Edward syndrome** is caused by **Trisomy 18** [1]. (Mnemonic: "E" for Edward and Eighteen). **High-Yield Clinical Pearls for NEET-PG:** * **Cytogenetics:** 95% are due to non-disjunction; 4% due to **Robertsonian translocation** (usually involving chromosome 14 or 22); 1% due to mosaicism [1]. * **Clinical Features:** Simian crease, Brushfield spots (iris), epicanthal folds, and macroglossia [1]. * **Cardiac Associations:** Endocardial cushion defects (ASD/VSD) are the most common. * **Gastrointestinal:** Duodenal atresia ("Double bubble" sign) and Hirschsprung disease. * **Future Risks:** Increased risk of **Acute Leukemia** (ALL and AML-M7) and early-onset **Alzheimer’s disease** (due to the APP gene on chromosome 21). * **Screening:** Low Alpha-fetoprotein (AFP) and high hCG/Inhibin-A in maternal quadruple screening. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 168-172.

Question 1

Which of the following is NOT a cause of edema?

Accepted Answer

Decreased intravascular pressure

Answer

Increased hydrostatic pressure

Answer

Decreased colloid osmotic pressure

Answer

Lymphatic obstruction

Question 2

CD-95 is a marker of which of the following?

Accepted Answer

Death receptor

Answer

MHC complex

Answer

T helper cells

Answer

NK cells

Question 3

What is Trisomy 21?

Accepted Answer

Down's syndrome

Answer

Turner syndrome

Answer

Klinefelter syndrome

Answer

Edward syndrome

Question 4

What substance is deposited in Bronze diabetes?

Accepted Answer

Iron

Answer

Bronze

Answer

Copper

Answer

Carbon

Question 5

What is the total number of chromosomes typically found in an individual with Turner syndrome?

Accepted Answer

45

Answer

47

Answer

46

Answer

42

Question 6

Development of the female breast at puberty is an example of:

Accepted Answer

Hypertrophy and hyperplasia

Answer

Hypertrophy

Answer

Hyperplasia

Answer

Atrophy

Question 7

Apoptosis is regulated by which gene?

Accepted Answer

p53

Answer

BRAC

Answer

N-myc

Answer

RB

Question 8

According to WHO classification, which class of membranous glomerulonephritis is typically seen in Systemic Lupus Erythematosus (SLE)?

Accepted Answer

Class V

Answer

Class II

Answer

Class III

Answer

Class IV

Question 9

Type 1 Dentinogenesis imperfecta is caused by mutation in which gene?

Accepted Answer

DSPP gene

Answer

DMP-1 gene

Answer

BSP-1 gene

Answer

SPP1 gene

Question 10

Amyloid is stained by which of the following stains?

Accepted Answer

Congo red

Answer

PAS

Answer

H & E

Answer

Methenamine silver

General Pathology — MCQs

General Pathology — MCQs

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