What are connexons?

• A. Pores between cells for communication; maintain electrical & metabolic continuity
• B. Structural proteins in tight junctions
• C. Anchoring proteins in adherens junctions
• D. Enzymes in basement membrane synthesis

Answer: (C)

Connexons form gap junctions, which are channels that physically connect neighboring cells to allow direct cytoplasmic exchange. Each connexon is made of six connexin proteins (a hemichannel), and when two hemichannels from adjacent cells align, they create a continuous pore between the cells. This pore lets ions and small molecules pass, producing electrical and metabolic coupling essential for coordinated tissue function, such as in heart and smooth muscle. The other options point to different structures: tight junctions use claudins and occludins to seal spaces between cells; adherens junctions rely on cadherins linked to the actin cytoskeleton via catenins for mechanical attachment; basement membrane components involve extracellular matrix proteins and related enzymes.