How does the structure of a plasmodesma differ from that of a gap junction?

Gap junction is a connecting channel in animal cell while plasmodesmata is connecting channel in plant cell.

Explanation:

Both Gap junction and plasmodesmata are form of connecting channel found in cell but Gap junction is found in animal cells while plasmodesmata is found in plant cell.

The structure of gap junction comprises of hemicahnnes (connexons). These hemichannels are made up of endoplasmic reticulum of cells that are later relocated by the Golgi apparatus to the cell membrane thereby forming transmembrane proteins named connexins. While Plasmodesmata are cylindrical in shape and lined with plasma membrane. There are narrow tubes known as desmotubules which are made up of smooth endoplasmic reticulum

There are three types of gap junction while there are several forms of plasmodesmata