Plasmodesmata

Cell junction only in plants.

Allows for communication and transfer of materials/hormones between plant cells.

Apoplastic: transport water and ions from the soil through root to xylem elements

Symplastic: transports hormones and allows communication between plant cells

Tight Junctions

Cell junction only in animals.

This junction binds two cells together like a strong glue.

It creates a watertight barrier so that nothing can pass between the cells. → no communication

Examples: bladder, intestines, kidneys

Desmosomes

Cell junctions only in animal cells.

These cell junctions are like spot welds. They bind the cells together but not so tightly, so that the tissues may handle stress and stretching.

Ions, water, and other materials are allowed to flow in the space between the cells.

The two cells are joined together by intermediate filaments (yellow).

Cytoplasmic Plaque (red): a layer on the inside of cells that makes it easier for intermediate filaments attach and anchor the junction

Cadherin (green): adhesion protein on outside of cells that allows intermediate filaments to attach onto the cytoplasmic plaque