Question

From the apical surface to the basal surface of an epithelial cell, what is the order of cell junctions observed in the junctional complex? a) Tight junction, gap junction, belt desmosome, spot desmosomes. b) Gap junctions, spot desmosomes, belt desmosome, tight junction. c) Belt desmosome, gap junctions, tight junctions, spot desmosomes. d) Belt desmosome, tight junction, gap junctions, spot desmosomes. e) Tight junction, belt desmosome, spot desmosomes, gap junctions.

Answer 1

The order of cell junctions from apical to basal surfaces in an epithelial cell is tight junction, belt desmosome, spot desmosomes, and gap junction.

Step-by-step explanation:

From the apical surface to the basal surface, the order of cell junctions observed in a junctional complex of epithelial cells is a tight junction, belt desmosome (zonula adherens), spot desmosomes (macula adherens), and gap junctions.

Starting with the tight junction, it forms a barrier that regulates the passage of substances and separates the cells into apical and basal compartments. Next, the belt desmosome (also known as zonula adherens), which uses cadherin molecules and actin filaments, encircles the cell to bind it to its neighbors.

Spot desmosomes (macula adherens) act like 'spot welds' to provide additional attachment points. Lastly, gap junctions create intercellular channels that allow for communication and the transfer of small molecules between cells.

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