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12 years ago
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Plasmodesmata (singular, plasmodesma) are microscopic channels of plants facilitating transport and communication between individual cells. Unlike animal cells, plant cells are protected by an impermeable cell wall; and as such, plasmodesmata are required for intercellular activity. Cells can utilize both passive and active transport to move molecules and ions through the passage. A plasmodesma is constructed of three main layers, the plasma membrane, the cytoplasmic sleeve, and the desmotubule.
Plasmodesmal Plasma Membrane
The plasma membrane portion of the plasmodesma is a continuous extension of the cellular plasmalemma. Similar in structure to most cellular phospholipid bilayers, the plasmodesmal membrane protects from loss of cytosol, protects from foreign materials such as pathogens, and provides anchoring for hydrophobic domains of proteins.
Cytoplasmic Sleeve
The cytoplasmic sleeve is enclosed by the plasma membrane and is an extension of the cytosol. Normally, no barrier separates the cytoplasm of two cells. Smaller molecules and ions such as sugars and amino acids can easily pass through by diffusion without the need for additional chemical energy. However, the ends of the plasmodesma, called neck regions, can contain closely associated proteins capable of contracting to regulate passage much like animal cell gap junctions.
Desmotubule
The desmotubule is a tightly woven phospholipid bilayer covered by actin and myosin filaments which traverses the plasmodesma. The desmotubule is connected directly to the endoplasmic reticulum of each of the adjacent cells forming a channel between the organelles of neighboring cells known as the dynamic endomembrane continuum. As such, the desmotubule is highly involved in intercellular polypeptide and lipid transport. Through the use of ATP, proteins associated with the desmotubule can expand the radius of the plasmodesma allowing larger unfolded proteins to pass through unimpeded.
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wrote...
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12 years ago
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The tremendous variety of plant species is, in part, a reflection of the many distinct cell types that make up individual plants. Fundamental similarities exist among all these cell types, however, and these similarities indicate the common origin and the interrelationships of the different plant species. Each individual plant cell is at least partly self-sufficient, being isolated from its neighbors by a cell membrane, or plasma membrane, and a cell wall. The membrane and wall allow the individual cell to carry out its functions; at the same time, communication with surrounding cells is made possible through cytoplasmic connections called plasmodesmata.
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wrote...
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12 years ago
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The tremendous variety of plant species is, in part, a reflection of the many distinct cell types that make up individual plants. Fundamental similarities exist among all these cell types, however, and these similarities indicate the common origin and the interrelationships of the different plant species. Each individual plant cell is at least partly self-sufficient, being isolated from its neighbors by a cell membrane, or plasma membrane, and a cell wall. The membrane and wall allow the individual cell to carry out its functions; at the same time, communication with surrounding cells is made possible through cytoplasmic connections called plasmodesmata
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wrote...
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12 years ago
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Plasmodesmata (singular, plasmodesma) are microscopic channels of plants facilitating transport and communication between individual cells. Unlike animal cells, plant cells are protected by an impermeable cell wall; and as such, plasmodesmata are required for intercellular activity. Cells can utilize both passive and active transport to move molecules and ions through the passage. A plasmodesma is constructed of three main layers, the plasma membrane, the cytoplasmic sleeve, and the desmotubule.
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wrote...
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12 years ago
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u hav got many detailed answers. but i'll giv a very simple ans in a few words. Plasmodesmata r the cytoplasmic tunnels or strands that connect one cell to another for transport or exchange of essentials thins like nutrients
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wrote...
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12 years ago
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They are microscopic cytoplasmic canals that pass through plant-cell walls and allow direct communication of molecules between adjacent plant cells. Plasmodesmata are formed during cell division, when traces of the endoplasmic reticulum (an organelle that synthesizes constituents of the outer cell membrane) become caught in the new wall that divides the parent cell. The two progeny cells may be connected by thousands of plasmodesmata, which contain rings of membrane at each end that are thought to regulate the passage of molecules. By overcoming the cell-wall barrier, plasmodesmata unite plant cells into functioning tissues.
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wrote...
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12 years ago
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Plasmodesmata are micro-channels found between adjacent plant cell walls. They facilitate they movement of substances between adjacent cells. They are like intercellular freeways
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