Gap Junctions In Animal Cells Are Most Similar To ________ In Plant Cells?

Learning Outcomes

• Depict cell junctions plant in constitute cells (plasmodesmata) and fauna cells (tight junctions, desmosomes, gap junctions)

Extracellular Matrix of Animal Cells

Most animate being cells release materials into the extracellular infinite. The primary components of these materials are proteins, and the most abundant protein is collagen. Collagen fibers are interwoven with carbohydrate-containing protein molecules called proteoglycans. Collectively, these materials are called theextracellular matrix (Figure i). Not only does the extracellular matrix hold the cells together to form a tissue, just it also allows the cells within the tissue to communicate with each other. How tin can this happen?

Effigy 1. The extracellular matrix consists of a network of proteins and carbohydrates.

Cells accept protein receptors on the extracellular surfaces of their plasma membranes. When a molecule within the matrix binds to the receptor, it changes the molecular structure of the receptor. The receptor, in turn, changes the conformation of the microfilaments positioned only within the plasma membrane. These conformational changes induce chemical signals inside the jail cell that reach the nucleus and plough "on" or "off" the transcription of specific sections of DNA, which affects the production of associated proteins, thus changing the activities within the prison cell.

Blood clotting provides an case of the office of the extracellular matrix in cell communication. When the cells lining a blood vessel are damaged, they display a protein receptor called tissue factor. When tissue factor binds with another factor in the extracellular matrix, information technology causes platelets to adhere to the wall of the damaged blood vessel, stimulates the adjacent smoothen muscle cells in the blood vessel to contract (thus constricting the claret vessel), and initiates a serial of steps that stimulate the platelets to produce clotting factors.

Intercellular Junctions

Cells can also communicate with each other via direct contact, referred to as intercellular junctions. There are some differences in the ways that plant and animal cells do this. Plasmodesmata are junctions betwixt plant cells, whereas animal jail cell contacts include tight junctions, gap junctions, and desmosomes.

Plasmodesmata

In general, long stretches of the plasma membranes of neighboring plant cells cannot touch on ane another because they are separated past the prison cell wall that surrounds each jail cell. How then, can a constitute transfer water and other soil nutrients from its roots, through its stems, and to its leaves? Such transport uses the vascular tissues (xylem and phloem) primarily. At that place too exist structural modifications called plasmodesmata (atypical = plasmodesma), numerous channels that pass between prison cell walls of adjacent constitute cells, connect their cytoplasm, and enable materials to be transported from jail cell to prison cell, and thus throughout the plant (Figure 2).

Figure two. A plasmodesma is a channel between the jail cell walls of two side by side institute cells. Plasmodesmata permit materials to pass from the cytoplasm of one plant jail cell to the cytoplasm of an adjacent cell.

Tight Junctions

Atight junction is a watertight seal betwixt 2 next animal cells (Figure 3). The cells are held tightly against each other past proteins (predominantly two proteins called claudins and occludins).

Figure 3. Tight junctions class watertight connections between side by side animate being cells. Proteins create tight junction adherence.

This tight adherence prevents materials from leaking betwixt the cells; tight junctions are typically found in epithelial tissues that line internal organs and cavities, and comprise most of the skin. For case, the tight junctions of the epithelial cells lining your urinary float forestall urine from leaking out into the extracellular infinite.

Desmosomes

Besides found merely in animal cells aredesmosomes, which act like spot welds between side by side epithelial cells (Figure 4). Short proteins called cadherins in the plasma membrane connect to intermediate filaments to create desmosomes. The cadherins join two adjacent cells together and maintain the cells in a canvass-like germination in organs and tissues that stretch, like the pare, heart, and muscles.

Effigy iv. A desmosome forms a very strong spot weld between cells. Linking cadherins and intermediate filaments create information technology.

Gap Junctions

Gap junctions in animal cells are like plasmodesmata in institute cells in that they are channels between adjacent cells that allow for the transport of ions, nutrients, and other substances that enable cells to communicate (Figure 5). Structurally, nonetheless, gap junctions and plasmodesmata differ.

Figure v. A gap junction is a protein-lined pore that allows water and small molecules to laissez passer between adjacent fauna cells.

Gap junctions develop when a set of six proteins (called connexins) in the plasma membrane arrange themselves in an elongated donut-like configuration called a connexon. When the pores ("doughnut holes") of connexons in adjacent animal cells align, a channel between the two cells forms. Gap junctions are particularly important in cardiac muscle: The electric signal for the muscle to contract is passed efficiently through gap junctions, allowing the middle muscle cells to contract in tandem.

In Summary: Jail cell Junctions

Beast cells communicate via their extracellular matrices and are connected to each other via tight junctions, desmosomes, and gap junctions. Plant cells are connected and communicate with each other via plasmodesmata.

When protein receptors on the surface of the plasma membrane of an animate being cell bind to a substance in the extracellular matrix, a chain of reactions begins that changes activities taking place within the cell. Plasmodesmata are channels between adjacent establish cells, while gap junctions are channels between adjacent animate being cells. However, their structures are quite unlike. A tight junction is a watertight seal between 2 next cells, while a desmosome acts like a spot weld.

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Source: https://courses.lumenlearning.com/wm-biology1/chapter/reading-cell-junctions-in-plant-cells/#:~:text=Gap%20junctions%20in%20animal%20cells,to%20communicate%20(Figure%205).

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