33. Physical attachment between cell to cell or between cells to extracellular matrix imparts rigidity to a tissue. Which of the following characteristic is NOT true for cell
    junction?
    (1) Desmosomes are cell-cell anchoring junctions connecting intermediate filament in one cell with that in the next cell.
    (2) Hemi-desmosomes are cell matrix anchoring junctions connecting actin filament in one cell with that in the next cell.
    (3) Gap junctions in animals and plasmodesmata in plants are channel forming
    junctions.
    (4) Occluding junctions seal the gaps between cells to make the cell sheet into an impermeable barrier.

The statement that is NOT true about cell junctions is:

(2) Hemi-desmosomes are cell matrix anchoring junctions connecting actin filament in one cell with that in the next cell.

Explanation:

• Desmosomes (1) are indeed cell-cell anchoring junctions that connect intermediate filaments of one cell with those of the adjacent cell, providing mechanical strength.​

• Hemi-desmosomes (2), however, connect intermediate filaments (not actin filaments) inside the cell to the extracellular matrix, anchoring epithelial cells to the basal lamina. They do NOT connect actin filaments, nor do they connect adjacent cells; rather they connect cell to matrix.​

• Gap junctions (3) are channel-forming junctions that allow direct communication by permitting passage of small molecules between adjacent cells in animals. Similarly, plasmodesmata serve this function in plants.​

• Occluding junctions (4), also known as tight junctions, form impermeable barriers by sealing gaps between cells, controlling paracellular transport.​

Summary Table

Conclusion

Hemi-desmosomes anchor cells to the extracellular matrix via intermediate filaments, not actin filaments, and do not connect adjacent cells. Thus, statement (2) is false while the others are true, reflecting established cell biology.