When is an organism multicellular communicate?When neighboring cells adhere, interact, and physiologicallycommunicate

Contact is achieved in four ways:Tight junctions proteins in membranes that bond neighboring cellsDesmosomes intracellular filaments that adjoin cells (often creating a space for material movement)Gap junctions pores surrounded by transmembrane proteins direct material movement between cellsPlasmodesmata open channels within the plant cell wall that connect cells directly

Tight junctions, the plasma membranes of neighboring cells are very tightly pressedagainst each other, bound together byspecific proteinsDesmosomes (also called anchoring junctions) function like rivets, fastening cells together into strong sheets. Intermediate filaments made of sturdy keratin proteins anchor desmosomes in the cytoplasm. Desmosomes attach muscle cells to each other in a muscle.Gap junctions (communicating junctions) provide cytoplasmic channels from one cell to an adjacent cell and in this way are similar in their function to the plasmodesmata in plants. Gap junctions consist of membrane proteins that surround a pore through which ions, sugars, amino acids, and other small molecules may pass. Gap junctions are necessary for communication between cells in many types of tissues, including heart muscle, and in animal embryos.

PlasmodesmataThe cytoplasm of one plant cell is continuous with the cytoplasm of its neighbors via plasmodesmataCampbell et al, 2008

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