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The major polymers that make up wood (largely secondary cell walls) include: cellulose, 35-50%; xylan, 20-35%, a type of hemicellulose; lignin, 10-25%, a complex phenolic polymer that penetrates the spaces in the cell wall between cellulose, hemicellulose and pectin components, driving out water and strengthening the wall.
Cellulose is an organic compound with the formula (C 6 H 10 O 5) n, a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. [3] [4] Cellulose is an important structural component of the primary cell wall of green plants, many forms of algae and the oomycetes.
The secondary cell wall consists primarily of cellulose, along with other polysaccharides, lignin, and glycoprotein. It sometimes consists of three distinct layers - S 1 , S 2 and S 3 - where the direction of the cellulose microfibrils differs between the layers. [ 1 ]
Structure of a plant cell. 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 ...
Some eukaryotic cells (plant cells and fungal cells) also have a cell wall. Inside the cell is the cytoplasmic region that contains the genome (DNA), ribosomes and various sorts of inclusions. [2] The genetic material is freely found in the cytoplasm. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular.
Structure of xylan in hardwood. [1] Plant cell wall is composed of cellulose, hemicellulose, pectin and glycoproteins. [2] Hemicelluloses (a heterogeneous group of polysaccharides) cross-link glycans interlocking the cellulose fibers and form a mesh like structure to deposit other polysaccharides.
In contrast, each polymer of cellulose comprises 7,000–15,000 glucose molecules. [5] In addition, hemicelluloses may be branched polymers, while cellulose is unbranched. Hemicelluloses are embedded in the cell walls of plants, sometimes in chains that form a 'ground' – they bind with pectin to cellulose to form a network of cross-linked ...
Plant cellulose, which makes up the cell walls of most plants, is a tough, mesh-like bulkwork in which cellulose fibrils are the primary architectural elements. While bacterial cellulose has the same molecular formula as plant cellulose, it has significantly different macromolecular properties and characteristics. [8]