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Plasmodesma
Plasmodesmata (singular: plasmodesma) are microscopic channels which traverse the cell walls of plant cells and some algal cells, enabling transport and communication between them. Plasmodesmata evolved independently in several lineages, and species that have these structures include members of the Charophyceae, Charales, Coleochaetales and Phaeophyceae (which are all algae), as well as all embryophytes, better known as land plants. Unlike animal cells, almost every plant cell is surrounded by a polysaccharide cell wall. Neighbouring plant cells are therefore separated by a pair of cell walls and the intervening middle lamella, forming an extracellular domain known as the apoplast. Although cell walls are permeable to small soluble proteins and other solutes, plasmodesmata enable direct, regulated, symplastic transport of substances between cells. There are two forms of plasmodesmata: primary plasmodesmata, which are formed during cell division, and secondary plasmodesmata, which c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Cell
Plant cells are the cells present in Viridiplantae, green plants, photosynthetic eukaryotes of the kingdom Plantae. Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regulates turgor pressure, the absence of Flagellum, flagella or centrioles, except in the gametes, and a unique method of cell division involving the formation of a cell plate or phragmoplast that separates the new daughter cells. Characteristics of plant cells * Plant cells have cell walls composed of cellulose, hemicelluloses, and pectin and constructed outside the cell membrane. Their composition contrasts with the cell walls of fungus, fungi, which are made of chitin, of bacteria, which are made of peptidoglycan and of archaea, which are made of pseudopeptidoglycan. In many cases lignin or suberin are secreted by the protoplast as secondary wall laye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Cells
Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae. Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regulates turgor pressure, the absence of flagella or centrioles, except in the gametes, and a unique method of cell division involving the formation of a cell plate or phragmoplast that separates the new daughter cells. Characteristics of plant cells * Plant cells have cell walls composed of cellulose, hemicelluloses, and pectin and constructed outside the cell membrane. Their composition contrasts with the cell walls of fungi, which are made of chitin, of bacteria, which are made of peptidoglycan and of archaea, which are made of pseudopeptidoglycan. In many cases lignin or suberin are secreted by the protoplast as secondary wall layers inside the prima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pit (botany)
Pits are relatively thinner portions of the cell wall that adjacent cell (biology), cells can Cell communication, communicate or exchange fluid through. Pits are characteristic of cell walls with Cell wall#Rigidity of cell walls, secondary layers. Generally each pit has a complementary pit opposite of it in the neighboring cell. These complementary pits are called "pit pairs". Pits are composed of three parts: the pit chamber, the pit aperture, and the pit membrane. The pit chamber is the hollow area where the secondary layers of the cell wall are absent. The pit aperture is the opening at either end of the pit chamber. The pit membrane is the primary cell wall and middle lamella, or the membrane between adjacent cell walls, at the middle of the pit chamber. The primary cell wall at the pit membrane may also have depressions similar to the pit depressions of the secondary layers. These depressions are primary pit-fields, or primary pits. In the primary pit, the primordial pit pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symplast
The symplast of a plant is the region enclosed by the cell membranes, within which water and solutes can diffuse freely. By contrast the apoplast is any fluid-filled space within the cell wall and extracellular space. Neighbouring cells are interconnected by microscopic channels known as plasmodesmata that traverse the cell walls. These channels, allow the flow of small molecules such as sugars, amino acids, and ions between cells (from the inner part of one cell to the inner part of the next cell). Larger molecules, including transcription factors and plant viruses, can also be transported through with the help of actin structures. The symplast allows direct cytoplasm-to-cytoplasm flow of water and other nutrients along concentration gradients. In particular, symplastic flow is used in the root systems to bring in nutrients from soil. Nutrient solutes move in this way through three skin layers of the roots: from cells of the ''epidermis'', the outermost layer, through the ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Wall
A cell wall is a structural layer that surrounds some Cell type, cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, and functions as a selective barrier. Another vital role of the cell wall is to help the cell withstand osmotic pressure and mechanical stress. While absent in many eukaryotes, including animals, cell walls are prevalent in other organisms such as fungi, algae and plants, and are commonly found in most Prokaryote, prokaryotes, with the exception of Mollicutes, mollicute bacteria. The composition of cell walls varies across taxonomic groups, species, cell type, and the cell cycle. In Embryophyte, land plants, the primary cell wall comprises Polysaccharide, polysaccharides like cellulose, hemicelluloses, and pectin. Often, other Polymer, polymers such as lignin, suberin or cutin are anchored to or embedded in plant cell walls. Algae exhibit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charophyceae
Charophyceae is a class of charophyte green algae. AlgaeBase places it in division Charophyta. Extant (living) species are placed in a single order Charales, commonly known as "stoneworts" and "brittleworts". Fossil members of the class may be placed in separate orders, e.g. Sycidiales and Trochiliscales. Charophyceae is basal in the Phragmoplastophyta clade which contains the embryophytes (land plants).Hoek, C. van den, Mann, D. G. & Jahns, H. M. 1995''Algae: An Introduction to Phycology'' Cambridge University Press, Cambridge. McCourt, R. M., Chapman, R. L., Buchheim, M. & Mishler, B. D“Green Plants” Accessed 13 December 2007 In 2018, the first nuclear genome sequence from a species belonging to the Charophyceae was published: that of '' Chara braunii''. Description The thallus is erect with regular nodes and internodes. At each node there is a whorl of branches. The whole plant is calcified and ''Equisetum ''Equisetum'' (; horsetail) is the only living genus in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genes & Development
''Genes & Development'' is a peer-reviewed scientific journal covering molecular biology, molecular genetics, cell biology, and development. It was established in 1987 and is published twice monthly by Cold Spring Harbor Laboratory Press in association with The Genetics Society. According to the ''Journal Citation Reports'', the journal has a 2012 impact factor of 12.44, ranking it 14th out of 181 journals in the category "Cell Biology", third out of 40 journals in the category "Developmental Biology", and 7th out of 158 journals in the category "Genetics & Heredity". Over 1999–2004, the journal was ranked fifth in the "Molecular Biology and Genetics" category according to ''ScienceWatch'', with an average of 47 citations per paper. All issues are available online via the journal website as PDFs, with a text version additionally available from August 1997. Content over 6 months old is freely available. Since 1989, the editor-in-chief has been Terri Grodzicker (Cold Spring Harbo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytosol
The cytosol, also known as cytoplasmic matrix or groundplasm, is one of the liquids found inside cells ( intracellular fluid (ICF)). It is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondrion into many compartments. In the eukaryotic cell, the cytosol is surrounded by the cell membrane and is part of the cytoplasm, which also comprises the mitochondria, plastids, and other organelles (but not their internal fluids and structures); the cell nucleus is separate. The cytosol is thus a liquid matrix around the organelles. In prokaryotes, most of the chemical reactions of metabolism take place in the cytosol, while a few take place in membranes or in the periplasmic space. In eukaryotes, while many metabolic pathways still occur in the cytosol, others take place within organelles. The cytosol is a complex mixture of substances dissolved in water. Although water forms the large majority of the cytosol, its structure and proper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phospholipid Bilayer
The lipid bilayer (or phospholipid bilayer) is a thin polar membrane made of two layers of lipid molecules. These membranes form a continuous barrier around all cells. The cell membranes of almost all organisms and many viruses are made of a lipid bilayer, as are the nuclear membrane surrounding the cell nucleus, and membranes of the membrane-bound organelles in the cell. The lipid bilayer is the barrier that keeps ions, proteins and other molecules where they are needed and prevents them from diffusing into areas where they should not be. Lipid bilayers are ideally suited to this role, even though they are only a few nanometers in width, because they are impermeable to most water-soluble ( hydrophilic) molecules. Bilayers are particularly impermeable to ions, which allows cells to regulate salt concentrations and pH by transporting ions across their membranes using proteins called ion pumps. Biological bilayers are usually composed of amphiphilic phospholipids that hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasmalemma
The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the cytoplasm, interior of a Cell (biology), cell from the extracellular space, outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane Membrane fluidity, fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane membrane transport, controls the movement of substances in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Membrane
The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of a cell from the outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of a cell, being selectively permeable to ions and organic molecu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
