Cell-to-cell communication (gap junctions, plasmodesmata) Transitional Reasoning Download PDF

Questions

1. 1.

   In an experiment investigating direct intercellular communication, researchers microinjected a low-molecular-weight fluorescent dye into a single cell within an animal tissue and a plant tissue. In both samples, the dye diffused into immediately adjacent cells without entering the extracellular space. When the tissues were treated with a chemical agent that specifically degrades hexameric connexin protein complexes, dye diffusion ceased entirely in the animal tissue but remained unaffected in the plant tissue. Based on these findings, which statement correctly identifies the structures responsible for direct communication in these tissues?

   • A) Animal cells establish direct cytoplasmic flow via desmotubules crossing the extracellular matrix, whereas plant cells rely on connexon channels embedded within the middle lamella.
   • B) Animal cells share cytoplasmic contents through proteinaceous gap junctions, whereas plant cells communicate through membrane-lined plasmodesmata that traverse the cell wall.
   • C) Both plant and animal tissues share identical lipid-lined conduits that allow the unrestricted passage of large organelles directly across the extracellular fluid.
   • D) Plant cells regulate communication using tight junctions that seal the cell wall, whereas animal cells construct plasmodesmata during cytokinesis to link neighboring cytoplasms.