- In a tissue, cells are bound together by physical attachment between cell to cell or between cell to the extracellular matrix. The following are some of the characteristics of cell junctions:
A. Tight junctions are cell-cell junctions connecting the intermediate filament in one cell with that in the adjacent cell.
B. Desmosomes are cell-matrix anchoring junctions connecting actin filament in one cell to the extracellular matrix.
C. Gap junctions are channel-forming junctions allowing the passage of small water-soluble molecules from cell to cell.
D. Tight junctions are occluding junctions that seal the gap between two cells.
E. Hemidesmosomes are cell-matrix anchoring junctions connecting intermediate filaments in one cell to the extracellular matrix.
Which one of the following options represents the combination of ALL INCORRECT statements?
(1) A and B (2) Band D
(3) C and E (4) D and E
The combination of ALL INCORRECT statements is:
(1) (A) and (B)
Explanation:
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(A) Tight junctions are NOT cell-cell junctions connecting intermediate filaments between cells.
Tight junctions are occluding junctions that seal gaps between cells to prevent paracellular diffusion; they do not connect cytoskeletal elements. -
(B) Desmosomes are NOT cell-matrix anchoring junctions connecting actin filaments to extracellular matrix.
Desmosomes are cell-cell anchoring junctions connecting intermediate filaments between adjacent cells, not actin filaments or cell-matrix contacts. -
(C) Gap junctions are channel-forming junctions that allow passage of small water-soluble molecules from cell to cell—this statement is correct.
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(D) Tight junctions are occluding junctions sealing the gap between two cells—this statement is correct.
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(E) Hemidesmosomes are cell-matrix anchoring junctions connecting intermediate filaments in cells to the extracellular matrix—this statement is correct.
Summary Table
| Statement | Description | Correctness |
|---|---|---|
| A | Tight junctions connect intermediate filaments cell-cell | Incorrect (tight junctions are occluding, not cytoskeletal connectors) |
| B | Desmosomes connect actin filaments to ECM | Incorrect (desmosomes connect intermediate filaments cell-cell) |
| C | Gap junctions are channel-forming cell-cell | Correct |
| D | Tight junctions seal gaps between cells | Correct |
| E | Hemidesmosomes anchor intermediate filaments to ECM | Correct |
Conclusion
Statements (A) and (B) are incorrect regarding the characteristics of tight junctions and desmosomes, respectively. The others are accurate and reflect established cellular biology.
1 Comment
Kajal
November 7, 2025A and B