What is the Difference Between Gap Junctions and Plasmodesmata

The key difference between gap junctions and plasmodesmata is that gap junctions are the channels between adjacent animal cells, while plasmodesmata are channels between adjacent plant cells.

Gap junctions and plasmodesmata are two types of cell-cell interactions in animals and plants. Cell-cell interaction is the direct interaction between two cell surfaces. Cell-cell interaction plays a crucial role in the development and function of multicellular organisms. These interactions allow cells to communicate efficiently with each other in response to the changes in their surrounding environment. This ability to send and receive signals is an essential factor for the survival of the cell. Moreover, these cell-cell interactions help the organization of cells within a particular tissue. The loss of communication between cells through cell-cell interaction may result in uncontrollable cell growth and cancer.

1. Overview and Key Difference
2. What are Gap Junctions
3. What are Plasmodesmata
4. Similarities – Gap Junctions and Plasmodesmata
5. Gap Junctions vs Plasmodesmata in Tabular Form
6. Summary – Gap Junctions vs Plasmodesmata

What are Gap Junctions?

Gap junctions are intracellular connections between animal cell types. Normally, they directly connect the cytoplasm of two animal cells. This allows various molecules, ions, and electrical impulses to pass through a regulated gate between animal cells. A gap junction may also be called a nexus or macula communicans. Gap junctions were first discovered and described in 1953. One gap junction is composed of two hexameric proteins (hemichannels). They are known as connexions in vertebrates and innexons in invertebrates. The hemichannel pair connects across the intracellular space and bridges the gap between two animal cells. Gap junctions are similar to the plasmodesmata that join the plant cells.

Figure 01: Gap Junctions

Generally, gap junctions occur in virtually all tissues of the animal body. But they are absent in fully developed skeletal muscle cells and mobile cell types such as sperm or erythrocytes. Moreover, gap junctions are not found in simpler organisms such as sponges and slime molds. Ephapse is a point of contact between two or more nerve cells. However, gap junction is different from ephapse.

What are Plasmodesmata?

Plasmodesmata are channels between adjacent plant cells. Plasmodesmata are microscopic channels that travel across the cell walls of plant cells and some algal cells. Plasmodesmata enable the transportation and communication between these cells. Plasmodesmata can be identified in algal species such as Charophyceae, Charales, Coleochaetales, Phaeophyceae, and land plants such as embryophytes. There are two types of plasmodesmata: primary and secondary. Primary plasmodesmata are formed during cell division, while secondary plasmodesmata are formed between mature cells.

Figure 02: Plasmodesmata

Normally, primary plasmodesmata are formed when fractions of endoplasmic reticulum are trapped across middle lamella when new cell walls are synthesized between two newly divided plant cells. Eventually, they are converted to cytoplasmic connections. At the formation site, the wall is not thickened further, which allows thin areas known as pits to be formed in the walls. These pits typically pair up between adjacent cells. Furthermore, plasmodesmata may also be inserted into existing cell walls between non-dividing cells. They are called as secondary plasmodesmata.

What are the Similarities Between Gap Junctions and Plasmodesmata?

Gap junctions and plasmodesmata are two types of cell-cell interactions in animals and plants.
Both channels allow molecules to pass through in a regulated manner.
Both channels help cell communication and cell interactions.
These channels consist of proteins.
They play a vital role in organism survival.