Cell Adhesion MCQs

33 MCQs with clinical pearls · MBBS Biochemistry · Prof Jariya

Topics covered (9)

Cell Junctions — 9 MCQs
Cell Adhesion Molecules — 7 MCQs
Pemphigus Vulgaris — 5 MCQs
Cell Junctions and Adhesion Molecules — 4 MCQs
Atherosclerosis — 3 MCQs
Extravasation — 2 MCQs
Leukocyte Adhesion Deficiency — 1 MCQs
Asthma — 1 MCQs
Rheumatoid Arthritis — 1 MCQs

Sample MCQs with clinical pearls

A cancer patient has altered E-cadherin expression. E-cadherin-mediated cell-to-cell adhesion requires which ion for cadherin binding to adjacent cadherins?

A) Calcium ✔

B) Chloride

C) Magnesium

D) Potassium

E) Sodium

Calcium binds to extracellular cadherin domains → causes conformational rigidity → enables homophilic binding between E-cadherins on adjacent cells. Without calcium → cadherins are flexible → cannot bind adjacent cadherins → cell-cell adhesion lost. EDTA (calcium chelator) disrupts cadherin-mediated adhesion in vitro. Calcium is essential for maintaining epithelial tissue integrity. 📹 [VIDEO LINK]

Physical barriers between individual cells that prevent paracellular movement of molecules are formed by which of the following?

A) Adherens junctions

B) Desmosomes

C) Gap junctions

D) Hemidesmosomes

E) Tight junctions ✔

Tight junctions (zonula occludens) = physical barriers sealing the paracellular space. Components: claudins, occludins, ZO proteins. Prevent ions and molecules from crossing between cells — force transcellular transport. Also establish apical/basolateral membrane polarity. Disrupted in coeliac disease and IBD → leaky gut. 📹 [VIDEO LINK]

A dermatologist biopsies skin from a patient with pemphigus vulgaris and notes intraepidermal blistering with acantholysis. The junctions disrupted in pemphigus vulgaris link intermediate filaments between adjacent keratinocytes. These junctions are:

A) Desmosomes ✔

B) Gap junctions

C) Hemidesmosomes

D) Tight junctions

E) Zonulae adherentes

Desmosomes link keratin intermediate filaments BETWEEN adjacent cells. Extracellular: desmoglein + desmocollin. Intracellular plaque: desmoplakin + plakophilin → keratin IFs. Pemphigus vulgaris = IgG anti-desmoglein 1 and 3 → acantholysis → intraepidermal blister. [Diagram: Desmosome structure — extracellular desmoglein/desmocollin → intracellular plaque (desmoplakin + plakophilin) → keratin IFs. IgG antibody blocking desmoglein → gap forming → acantholysis. Tombstone pattern shown.] 📹 [VIDEO LINK]

These are three of 33 MCQs in this section. Every question carries a clinical pearl explaining the reasoning.

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