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Cell Signaling Problem Set

Problem 11: Gap Junctions

Tutorial to help answer the question

Direct cellular connections such as gap junctions in animal cells and plasmodesmata in plant cells permit:

A. adjacent cells to adhere strongly to each other.
B. second messengers produced in one cell to rapidly diffuse into and stimulate events in surrounding cells.
C. adjacent cells to form a water-tight barrier between their membranes.
D. protein kinases to flow between cells, coordinating cellular responses in a tissue.
E. the rapid exchange of genetic information between adjacent cells.


Gap junctions of animal cells and plasmodesmata of plant cells are protein structures that permit the movement of small molecules through pores in the cell membranes. Small molecules, ions, and signaling molecules are small enough to move through the protein pores.

Movement of signal molecules between cells may be an important part of the coordinated response of a tissue to an outside signal or ligand. Proteins and genetic information are too large to pass between cells through these junctions. These systems probably function to provide more rapid communication between cells.

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