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Chapter 1 Cell Walls and Plant Anatomy |
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1 | (42) |
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A. The Derivation of Cells and Their Walls |
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1 | (11) |
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1. Cells arise in specialized regions of the plant called meristems. |
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1 | (2) |
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2. Walls originate in dividing cells |
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3 | (1) |
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3. Plant organ development depends on precise control of the plane of cell division and of cell expansion |
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4 | (4) |
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4. Cytoskeletal elements predict the position of the new cross-wall before the cell divides |
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8 | (1) |
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5. Actin filaments help to position new cross-walls |
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9 | (1) |
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6. The new cross-wall must join and fuse with the mother cell wall |
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10 | (1) |
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7. A plant is constructed from two compartments: the apoplast and the symplast |
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10 | (2) |
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B. Walls in Cell Growth and Differentiation |
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12 | (9) |
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1. Cells become organized at an early stage into three major tissue systems |
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12 | (4) |
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2. When they have stopped dividing, cells usually continue to grow in size |
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16 | (1) |
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3. Depending on its position in the plant, a cell differentiates into a specific cell type |
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17 | (1) |
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4. A distinction is often made between primary and secondary walls |
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18 | (2) |
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5. Differentiated cell types are often characterized by functionally specialized cell walls |
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20 | (1) |
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C. Plant Cell Types and Their Walls |
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21 | (22) |
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1. Shoot epidermal cells produce a waterproof cuticle that helps provide protection |
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21 | (1) |
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2. Stomatal guard cells have asymmetrically thickened walls that allow them to reversibly change shape |
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22 | (2) |
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3. Cells in ground tissues fill the space between epidermis and vascular tissue |
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24 | (1) |
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4. The endodermis regulates the flow of solutes through the apoplast of the root |
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25 | (1) |
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5. The pericycle encircles the vascular tissue and can give rise to lateral roots |
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26 | (1) |
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6. Xylem vessel elements are pipes that conduct water at negative pressure |
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27 | (2) |
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7. Phloem sieve tube elements are high-pressure tubes for conducting sugar solutions |
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29 | (2) |
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8. Transfer cells load solutes into and out of conducting elements |
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31 | (1) |
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9. Plasmodesmata allow adjacent cells to communicate with each other across their intervening walls |
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32 | (2) |
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10. Collenchyma and sclerenchyma provide support in young tissues |
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34 | (1) |
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11. The shaping of mesophyll cells generates large air spaces that facilitate gaseous diffusion |
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34 | (3) |
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12. Pollen grains have a unique and sculptured protective wall |
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37 | (1) |
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13. Some plant cells have no walls |
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37 | (2) |
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39 | (1) |
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39 | (4) |
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Chapter 2 The Structural Polysaccharides of the Cell Wall and How They are Studied |
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43 | (24) |
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43 | (9) |
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1. Primary walls isolated in a variety of ways contain the same structural polymers |
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43 | (1) |
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2. Cellulose is a β-1, 4-linked glucan with a disaccharide repeating unit |
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44 | (1) |
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3. Pectins and hemicelluloses are the noncellulosic polysaccharides of primary walls |
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45 | (1) |
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4. Wall polysaccharides are composed of 13 different sugars |
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45 | (1) |
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5. Homogalacturonan, rhamnogalacturonan I, and rhamnogalacturonan II are three pectic polysaccharides in primary walls |
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45 | (2) |
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6. Xyloglucans and arabinoxylans are the two major hemicellulosic polysaccharides in primary walls |
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47 | (1) |
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7. The structural characterization of polysaccharides is difficult |
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47 | (1) |
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8. Cell walls contain proteins, glycoproteins, and proteoglycans that perform enzymatic, structural, defensive, and other functions |
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48 | (1) |
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9. Primary cell walls contain an aqueous phase |
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49 | (1) |
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10. Secondary walls are composed of primary walls plus additional layers of polymers |
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49 | (3) |
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B. Methods for Characterizing the Structural Polysaccharides of the Cell Wall |
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52 | (15) |
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1. Obtaining pure polysaccharides is a prerequisite for primary structure determination |
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52 | (1) |
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2. Extracellular polysaccharides secreted by cultured cells are excellent models for wall polysaccharides |
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53 | (1) |
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3. Enzymatic and chemical cleavage of polysaccharides has made structural studies possible |
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53 | (1) |
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4. Several methods are used for glycosyl composition analysis |
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54 | (3) |
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5. Glycosyl linkage compositions are determined by methylation analysis |
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57 | (1) |
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6. Glycosyl sequencing of oligo-and polysaccharides is not routine |
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57 | (1) |
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7. Nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) are important tools for determining the structures of polysaccharides |
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58 | (4) |
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8. The conformations of cell wall oligo-and polysaccharides can be investigated using NMR and computational methods |
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62 | (1) |
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9. The structure of cellulose has been determined by X-ray diffraction techniques |
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63 | (1) |
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64 | (1) |
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64 | (3) |
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Chapter 3 Biochemistry of the Cell Wall Molecules |
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67 | (52) |
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67 | (1) |
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1. β-Glucan chains hydrogen-bond together to form cellulose microfibrils |
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67 | (1) |
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2. The glucan chains of cellulose microfibrils all have the same orientation |
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67 | (1) |
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68 | (7) |
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1. Xyloglucan is a principal hemicellulose of cell walls |
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68 | (1) |
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2. The structural features of xyloglucan have been defined by analysis of endoglucanase-released oligosaccharides |
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69 | (2) |
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3. Side chain substitutions on the backbone of xyloglucan affect endoglucanase cleavage of the backbone |
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71 | (1) |
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4. Arabinoxylan is the predominant hemicellulose of grasses |
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72 | (1) |
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5. The elucidation of arabinoxylan structures has been facilitated by characterizing oligosaccharides generated by endoxylanases |
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73 | (1) |
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6. Secondary walls contain xylans and glucomannans |
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74 | (1) |
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7. A galacturonic acid-containing oligosaccharide is found at the reducing end of glucuronoxylans |
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74 | (1) |
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C. Pectic Polysaccharides |
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75 | (6) |
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1. Homogalacturonans are gel-forming polysaccharides |
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75 | (1) |
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2. Rhamnogalacturonan I (RG-I) is a family of large polysaccharides with a backbone of repeating disaccharide units |
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75 | (2) |
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3. Rhamnogalacturonan I (RG-I) has many arabinosyl and galactosyl residue-containing side chains |
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77 | (1) |
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4. Rhamnogalacturonan II (RG-II) is the most complex polysaccharide known |
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78 | (2) |
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5. Rhamnogalacturonan II (RG-II) has an oligogalacturonide backbone |
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80 | (1) |
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6. Rhamnogalacturonan II (RG-II) has side chains with unique structures |
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80 | (1) |
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D. Other Wall Polysaccharides |
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81 | (4) |
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1. β1, 3/1, 4-(mixed-linked) glucans are found in grasses and horsetail |
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81 | (1) |
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2. Enzyme-generated oligosaccharides have been used to structurally characterize mixed-linked glucans |
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82 | (1) |
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3. Callose is a β-1, 3-D-glucan |
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82 | (1) |
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4. Substituted galacturonans are found in some cell walls |
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83 | (1) |
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5. Galactoglucomannans are found in Solanaceae cell walls and in the growth medium of Solanaceae cultured cells |
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83 | (1) |
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6. Some seed cell walls contain storage polysaccharides |
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84 | (1) |
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7. Gums are secreted in response to stress and are not normally considered to be wall components |
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84 | (1) |
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E. Proteins and Glycoproteins |
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85 | (10) |
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1. Plant cell walls contain structural, enzymatic, lipid transfer, signaling, and defense proteins |
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85 | (1) |
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2. The repeated sequence motifs of structural proteins define their classes and their physical properties |
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86 | (1) |
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3. Sequence motifs define proline hydroxylation, glycosylation, and intra-and intermolecular cross-linking sites |
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87 | (1) |
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4. HRGP and PRP expression is controlled by developmental programs and triggered by external stimuli |
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88 | (1) |
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5. Extensin-type HRGPs are rod-shaped molecules that become insolubilized by a peroxide-mediated cross-linking process |
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89 | (1) |
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6. Arabinogalactan proteins form a family of complex proteoglycans located at the cell-surface, and in the cell wall and intercellular space |
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90 | (2) |
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7. Classical arabinogalactan proteins are GPI-anchored proteoglycans |
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92 | (2) |
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8. GRPs are structural cell wall proteins that participate in the assembly of vascular bundles and are present in root cap mucilage |
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94 | (1) |
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9. AGPs, GRPs, HRGPs, and PRPs may have a common evolutionary origin |
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95 | (1) |
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95 | (11) |
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1. Lignin is a hydrophobic polymer of secondary cell walls |
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95 | (1) |
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2. Our knowledge of lignin composition is based on the chemical hydrolysis of wood |
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96 | (3) |
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3. Lignins in plant tissues, cells, and cell walls may be detected by histochemical staining or immunochemical localization |
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99 | (1) |
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4. The complexity of ligning is increased by the diversity of intermolecular linkages |
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100 | (2) |
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5. Models for higher-order structure of lignin |
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102 | (1) |
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6. Lignin is cross-linked to polysaccharide components in lignin-carbohydrate complexes |
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103 | (1) |
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7. Lignin composition and content vary greatly among the major groups of higher plants |
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104 | (1) |
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8. Lignin content and composition vary in wood formed during increased mechanical stress |
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105 | (1) |
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G. Suberin, Cutin, Waxes, and Silica |
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106 | (13) |
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1. Suberin is a complex hydrophobic material that forms physical and biological barriers essential for plants |
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110 | (1) |
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3. Epicuticular waxes form the primary interface between the outside of the plant and the aerial environment |
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111 | (1) |
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4. Silica deposits are formed on the surface of epidermal cells as well as within the cell walls of internal tissues of many herbaceous and woody plants |
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111 | (2) |
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113 | (1) |
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113 | (6) |
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Chapter 4 Membrane Systems Involved in Cell Wall Assembly |
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119 | (42) |
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A. Sites of Cell Wall Polymer Assembly in Interphase Cells |
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120 | (25) |
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1. Different polymers are synthesized at different locations, in the ER and the Golgi apparatus, at the plasma membrane, or in the cell wall |
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120 | (1) |
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2. The endoplasmic reticulum consists of a three-dimensional membrane network that extends throughout the cytoplasm and is differentiated into specialized domains |
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121 | (1) |
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3. Golgi stacks consist of sets of flattened cisternae that are structurally distinct and exhibit a polar architecture |
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122 | (2) |
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4. Plant Golgi stacks are dispersed throughout the cytoplasm, travel along actin filament tracks with myosin motors, and stop at ER export sites |
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124 | (1) |
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5. COPII vesicles bud from the ER with an external scaffold that is transferred with the vesicles to the cis side of the Golgi stacks, giving rise to the Golgi scaffold (matrix) |
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125 | (2) |
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6. Intra-Golgi transport of membrane and cargo molecules is best explained by the cisternal progression/maturation model |
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127 | (1) |
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7. The trans Golgi network cisternae of plants are transient organelles that sort and package Golgi products into secretory and clathrin-coated vesicles |
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128 | (3) |
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8. Maintenance of an appropriate pH in different Golgi compartments is essential for their functions |
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131 | (1) |
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9. Golgi stacks are structurally and functionally differentiated in a tissue-and developmental stage-specific manner |
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132 | (1) |
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10. The process of exocytosis delivers matrix molecules to the cell wall and membrane molecules to the plasma membrane |
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133 | (1) |
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11. Turgor pressure has profound effects on vesicle-mediated secretion, membrane recycling from the plasma membrane, and the movement of secreted molecules through cell walls |
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134 | (2) |
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12. Cellulose microfibrils, callose, and mixed-linked glucans are made by enzyme complexes in the plasma membrane |
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136 | (1) |
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13. The enzymes that synthesize cellulose microfibrils in higher plants are organized into complexes that visually look like rosettes |
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137 | (1) |
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14. Cellulose synthase complexes are pushed forward in the plasma membrane by the growing cellulose microfibrils that they extrude into the cell wall |
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137 | (2) |
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15. Rosette complexes are concentrated in domains of the plasma membrane underlying sites of rapid cellulose synthesis |
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139 | (2) |
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16. The half-life of rosette complexes determines the length of cellulose microfibrils |
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141 | (1) |
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17. The cellulose microfibrils of primary cell walls are shorter than those of secondary cell walls |
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142 | (1) |
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18. Callose appears transiently during growth and development and is also formed in response to biotic and abiotic stresses |
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142 | (1) |
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19. Callose is a transient cell wall component that is critically important for many growth and developmental processes |
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143 | (1) |
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20. Stress-induced callose synthesis serves to protect cells from potentially lethal biotic and abiotic insults |
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144 | (1) |
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B. Membrane Systems Involved in De Novo Cell Wall Assembly during Cytokinesis |
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145 | (16) |
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1. Plant Golgi stacks multiply by division |
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145 | (1) |
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2. During mitosis and cytokinesis cytoplasmic streaming stops and the Golgi stacks redistribute to specific locations |
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145 | (2) |
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3. Somatic-type cell plate formation can be divided into four distinct phases |
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147 | (3) |
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4. Dynamin-GTPases create dumbbell-shaped, cell plateforming vesicles containing dehydrated and possibly gelled cell wall-forming molecules |
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150 | (2) |
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5. The association of cisternae of the endoplasmic reticulum with forming cell plates increases over time, but the functional importance of this spatial relationship has yet to be fully explored |
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152 | (1) |
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6. Formation of cell walls in the syncytial endosperm and in meiocytes involves a special kind of cell plate, the syncytial-type cell plate |
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153 | (4) |
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157 | (1) |
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157 | (4) |
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Chapter 5 Biosynthesis of Cell Wall Polymers |
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161 | (66) |
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A. General Mechanisms of Polymer Assembly |
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161 | (14) |
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1. Polymers are assembled from building blocks |
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161 | (1) |
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2. Nucleotide sugars are the source of the glycosyl residue building blocks used in the synthesis of cell wall polysaccharides and glycoproteins |
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162 | (4) |
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3. Transport of nucleotide sugars into ER and Golgi cisternae is mediated by specific NDP-sugar/NMP antiporters |
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166 | (1) |
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4. Wall polysaccharides are made by membrane-bound polysaccharide synthases and glycosyltransferases |
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167 | (1) |
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5. Glycosyltransferases are generally nonabundant proteins |
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167 | (1) |
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6. All glycosidases and glycosyltransferases involved in the modification of glycoproteins and polysaccharides have a common topology and common Golgi retention mechanisms |
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168 | (1) |
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7. The synthesis of polysaccharide backbones involves initiation, elongation, and termination reactions |
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168 | (4) |
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8. Polysaccharide synthases can be identified biochemically by substrate and activator binding activities, by product entrapment techniques, and by catalytic activities detected in nondenaturing gels |
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172 | (1) |
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9. The three-dimensional structure of the backbone of cell wall polysaccharides suggests synthesis by glycosyltransferases with two active sites |
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172 | (3) |
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10. Polysaccharide synthesis is carefully controlled, but the control points are still poorly understood |
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175 | (1) |
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B. Assembly and Processing of Glycoproteins and Proteoglycans |
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175 | (7) |
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1. N-linked glycans of glycoproteins are assembled on dolichol lipids |
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175 | (2) |
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2. Newly synthesized N-linked glycans are transferred en bloc to nascent polypeptides and immediately subjected to processing by two glucosidases |
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177 | (1) |
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3. Processing of N-linked glycans in the plant Golgi apparatus is similar but not identical to the processing in other organisms |
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178 | (1) |
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4. The sites of O-linked glycosylation are defined in part by rules of proline hydroxylation |
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179 | (2) |
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5. The GPI anchors of arabinogalactan proteins are both synthesized and attached to the protein backbone in the ER |
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181 | (1) |
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C. Assembly of Polysaccharides in the Endomembrane System |
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182 | (11) |
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1. The backbones of some complex polysaccharides are synthesized by Golgi-located enzymes encoded by genes of the cellulose synthase-like (CSL) gene family |
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182 | (2) |
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2. Synthesis of the glucan backbone of xyloglucan in trans Golgi cisternae is enhanced by the cooperative assembly of glucosyl and xylosyl residues |
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184 | (1) |
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3. The XG-fucosyl and XG-galactosyltransferases can add fucosyl and galactosyl residues during or after synthesis of the XG backbone |
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185 | (1) |
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4. The assembly of xyloglucan occurs in trans Golgi and early trans Golgi network eisternae |
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186 | (1) |
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5. The large number of enzymes needed to make pectic polysaccharides makes understanding their synthesis a challenge |
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186 | (3) |
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6. Synthesis of pectic polysaccharides involves enzymes localized to late cis, medial, and trans Golgi cisternae |
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189 | (1) |
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7. Only a few steps of the pectic polysaccharide synthesis pathway have been studied biochemically in vitro |
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189 | (2) |
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8. The biosynthesis of galactomannans has parallels to the biosynthesis of xyloglucans |
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191 | (1) |
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9. Several glycosyltransferases involved in xylan biosynthesis have been identified, but the mechanism of xylan biosynthesis remains obscure |
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192 | (1) |
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D. Assembly of Polysaccharides at the Plasma Membrane |
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193 | (10) |
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1. Studies of cellulose synthesis by Gluconacetobacter xylinus (Acetobacter xylinum) provided many of the paradigms for similar studies in higher plants |
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193 | (1) |
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2. Hydrophobic cluster analysis played a critical role in the identification of the plant CESA genes |
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193 | (1) |
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3. Plant CESA genes appear to be derived from cyanobacterial precursors |
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194 | (1) |
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4. The cellulose synthase (CESA) proteins appear to correspond to the catalytic subunits of cellulose synthase complexes |
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195 | (1) |
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5. The CESA protein is an integral protein with several domains characteristic of processive glycosyltransferases |
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196 | (1) |
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6. The Zn-binding domains of CESA and some CSLD proteins appear to mediate dimerization of the catalytic subunits of cellulose synthases |
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197 | (1) |
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7. The cellulose-synthesizing rosette complexes are composed of three different types of CESA proteins |
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198 | (1) |
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8. The involvement of KORRIGAN, a β-1, 4-glucanase, in cellulose synthesis has yet to be proven conclusively |
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198 | (1) |
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9. UDP-glucose, the substrate for the cellulose and callose synthase systems, may be produced by a membrane-bound form of sucrose synthase |
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199 | (1) |
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10. There are two types of callose synthase systems, a Ca21-dependent and a Ca2+-independent type |
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200 | (1) |
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11. Callose synthase is a large protein that differs in many ways from cellulose synthase |
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201 | (1) |
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12. The ratio of tri-and tetrasaccharide units in mixed-linked glucans made in vitro can be altered experimentally |
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202 | (1) |
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E. Polymer Assembly in the Wall: Biosynthesis of Lignins, Waxes, Cutins, and Suberins |
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203 | (24) |
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1. The secondary cell wall provides a unique environment for the polymerization of lignins from cinnamyl alcohols |
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203 | (1) |
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2. Cinnamyl alcohols are the predominant precursors for lignin biosynthesis |
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203 | (3) |
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3. Monolignols are formed by successive enzymatic modifications of phenylalanine |
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206 | (1) |
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4. Hydroxylation and O-methylation at the 3 and 5 positions on the aromatic ring are unlikely to take place at the level of cinnamic acids |
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207 | (1) |
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5. Coniferaldehyde is the branch point for the biosynthesis of coniferyl alcohol and sinapyl alcohol |
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208 | (1) |
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6. Monolignols are glucosylated, stored, transported, and deglycosylated before polymerization |
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208 | (2) |
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7. Lignin polymers are formed through enzymatic oxidation of monolignols |
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210 | (2) |
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8. Lignin polymerization is primarily due to the addition of a monolignol to a lignin polymer |
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212 | (1) |
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9. Oxidative carriers or radical mediators may be involved in the polymerization process |
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213 | (1) |
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10. A nonenzymatic model for lignin polymerization has been proposed involving "dirigent" or guide proteins |
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214 | (1) |
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11. Nontraditional monomers are readily incorporated into lignin, indicating a high level of metabolic plasticity |
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215 | (1) |
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12. The deposition of lignin is both temporally and spatially controlled |
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216 | (1) |
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13. The composition of lignin differs between cell wall domains and cell types |
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217 | (1) |
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14. The biosynthesis of cutins, suberins, and waxes involves enzymes in chloroplasts, the endoplasmic reticulum, and cell walls |
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218 | (3) |
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221 | (1) |
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222 | (5) |
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Chapter 6 Principles of Cell Wall Architecture and Assembly |
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227 | (46) |
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A. Cross-Links between Wall Polymers |
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227 | (8) |
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1. Wall polymers are cross-linked by covalent bonds as well as by noncovalent bonds and interactions |
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227 | (1) |
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2. Hemicelluloses bind strongly to cellulose microfibrils by noncovalent bonds |
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228 | (1) |
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3. Hemicelluloses cross-link cellulose microfibrils |
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229 | (1) |
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4. Pectic polysaccharides are probably covalently interconnected by glycosidic bonds |
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229 | (1) |
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5. Homogalacturonans and partially methylesterified homogalacturonans form gels |
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230 | (1) |
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6. Borate esters cross-link RG-II dimers in the wall |
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231 | (1) |
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7. Diferulic acids probably cross-link wall polysaccharides |
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232 | (1) |
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8. Transesterification may produce other possible cross-links |
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233 | (1) |
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9. Some wall proteins become insolubilized by covalent cross-links |
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233 | (1) |
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10. Lignin is covalently attached to hemicelluloses, and their interaction adds strength to the secondary cell wall |
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234 | (1) |
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B. Architectural Principles: Putting the Polymers Together |
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235 | (15) |
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1. Two coextensive polysaccharide networks underlie the structure of the primary cell wall |
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235 | (1) |
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2. Walls are constructed of lamellae that are one cellulose microfibril thick |
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236 | (1) |
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3. The primary wall is usually composed of only a small number of lamellae |
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236 | (1) |
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4. The spacing of cellulose microfibrils is determined by matrix polysaccharides |
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237 | (3) |
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5. The walls of cells in which cellulose synthesis has been inhibited are composed largely of a pectin network |
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240 | (1) |
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6. The pectin network limits the porosity of the wall |
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241 | (1) |
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7. The cell controls the thickness of its wall |
|
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242 | (1) |
|
8. How proteins are integrated into wall architecture is unclear |
|
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243 | (1) |
|
9. The orientation of newly synthesized microfibrils is determined by the cell |
|
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244 | (2) |
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10. The orientation of microfibrils within a wall may change during growth |
|
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246 | (2) |
|
11. The self-ordering properties of polylamellate walls can lead to high degrees of structural order |
|
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248 | (1) |
|
12. Cell wall assembly is a hierarchical process |
|
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249 | (1) |
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C. Architectural Variations: The Mosaic Wall |
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250 | (23) |
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1. Polymers are not evenly distributed within a wall |
|
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250 | (2) |
|
2. The middle lamella forms an adhesive boundary between adjacent cells |
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252 | (4) |
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3. Three-way junctions are rich in protein, pectin, and phenolics |
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256 | (1) |
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4. The middle lamella is involved in cell separation |
|
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257 | (1) |
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5. The intercellular spaces form a continuum |
|
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258 | (2) |
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6. The expression of arabinogalactan proteins is developmentally regulated |
|
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260 | (1) |
|
7. A cell wall is the product of both a cell's internal developmental program and its environmental history |
|
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261 | (1) |
|
8. Wall composition and architecture, together with anatomy, contribute to the mechanical properties of plants and their products |
|
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262 | (2) |
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9. Models of the cell wall have helped us to think more clearly about their construction and function |
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264 | (4) |
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268 | (1) |
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268 | (5) |
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Chapter 7 The Cell Wall in Growth and Development |
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273 | (46) |
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A. Interactions Between the Cytoskeleton and the Wall |
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273 | (9) |
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1. Cortical microtubule reorientation changes the orientation of cellulose microfibril deposition during growth |
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273 | (3) |
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2. Intracellular factors can alter the orientation of cortical microtubules |
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276 | (1) |
|
3. Bundles of microtubules can define distinct domains of the wall that will thicken during cell development |
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277 | (1) |
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4. The arrangement of cytoskeletal elements in one cell often relates to that in a neighboring cell |
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278 | (3) |
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5. The wall is attached to receptor-like proteins in the plasma membrane |
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281 | (1) |
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282 | (12) |
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1. A key driver of plant growth is postmitotic cell expansion |
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282 | (2) |
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2. Cell expansion is usually accompanied by the deposition of new wall material |
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284 | (3) |
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3. Wall architecture underpins anisotropic cell expansion |
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287 | (3) |
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4. Dynamic remodeling of wall architecture facilitates cell expansion |
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290 | (2) |
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5. Proteins that enhance wall expansion have been identified |
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292 | (2) |
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6. Acidification of the wall, enhanced by auxin, may promote cell expansion |
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294 | (1) |
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C. Turnover, Remodeling, and Breakdown of the Wall |
|
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294 | (12) |
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1. Although plant cell walls are relatively stable compartments, many matrix polysaccharides and proteoglycans do turn over |
|
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294 | (2) |
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2. The de novo insertion of plasmodesmata across established walls requires wall remodeling |
|
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296 | (2) |
|
3. Local removal of wall material is used to create conducting elements from files of cells |
|
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298 | (1) |
|
4. Abscission of leaves and fruit is an active process that involves controlled cell separation |
|
|
299 | (1) |
|
5. Fruit softening depends upon the expression and activity of cell wall-modifying proteins |
|
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300 | (2) |
|
6. In some seeds, wall polysaccharides can form a food reserve to be used during germination |
|
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302 | (1) |
|
7. Lignin and suberin provide physical barriers to the turnover and degradation of secondary walls |
|
|
303 | (1) |
|
8. Gravity sensing and mechanical stress lead to compensatory changes in cell wall synthesis and architecture |
|
|
304 | (2) |
|
D. Cell Wall-Derived Signals in Growth and Development |
|
|
306 | (13) |
|
1. Many signals combine to regulate plant growth |
|
|
306 | (2) |
|
2. Oligogalacturonides can modulate development in tobacco explants |
|
|
308 | (1) |
|
3. Xyloglucan-derived oligosaccharins can affect the rate of elongation growth |
|
|
308 | (2) |
|
4. Lipo-oligosaccharides synthesized by rhizobia regulate nodule development in host plants |
|
|
310 | (1) |
|
5. Chitinases may function during normal plant development |
|
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311 | (2) |
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313 | (1) |
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|
313 | (6) |
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Chapter 8 Cell Walls and Plant-Microbe Interactions |
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|
319 | (46) |
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319 | (1) |
|
A. How Plants Detect and Respond to Microbes |
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|
320 | (11) |
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1. Most plants are immune to most pathogens |
|
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320 | (1) |
|
2. Signals from both pathogen and host can elicit a common defense response |
|
|
321 | (1) |
|
3. Cell surface receptors recognize common molecular patterns |
|
|
322 | (2) |
|
4. The plant's responses to danger involve a common sequence of events |
|
|
324 | (2) |
|
5. Some specialist pathogens deliver effectors to suppress the basal defense response |
|
|
326 | (2) |
|
6. Some defenses are preformed |
|
|
328 | (1) |
|
7. Defense can also be mounted at a distance |
|
|
329 | (2) |
|
B. The Wall as a Battleground |
|
|
331 | (20) |
|
Pathogens enter either by force, through wounds, or through natural openings |
|
|
331 | (2) |
|
2. Plasmodesmata provide a route for pathogen spread |
|
|
333 | (2) |
|
3. Callose deposition is a local response to both pathogens and wounding |
|
|
335 | (1) |
|
4. Wall strengthening helps contain the pathogen |
|
|
336 | (2) |
|
5. Cell polarization is a common response to a pathogen |
|
|
338 | (2) |
|
6. Localized cell death restricts pathogen spread |
|
|
340 | (1) |
|
7. Cell wall fragments act as danger signals |
|
|
341 | (2) |
|
8. Plants and pathogens battle to control the release of oligogalacturonides |
|
|
343 | (1) |
|
9. PR proteins attack the walls of fungi and bacteria |
|
|
344 | (1) |
|
10. Carbohydrate-binding modules (CBMs) help enzymes attach to the wall |
|
|
345 | (1) |
|
11. Cell wall integrity is sensed by the host |
|
|
346 | (2) |
|
12. Responses to wounding and pathogens overlap |
|
|
348 | (1) |
|
13. Wall-degrading enzymes and their inhibitors coevolve |
|
|
349 | (2) |
|
C. Recycling of Cell Walls |
|
|
351 | (14) |
|
1. Removing pectin is a key early step in dismantling the wall |
|
|
352 | (1) |
|
2. Lyases are important pectic enzymes for both necrotrophic pathogens and saprophytic microbes |
|
|
353 | (3) |
|
3. To fully digest hemicelluloses, enzymes act in concert |
|
|
356 | (1) |
|
4. Cellulose is tough, and its disassembly usually requires special machinery |
|
|
357 | (3) |
|
|
|
360 | (1) |
|
|
|
360 | (5) |
|
Chapter 9 Plant Cell Walls: A Renewable Material Resource |
|
|
365 | (42) |
|
A. Effects of Cell Walls on the Nutritional Quality and Texture of Foods and Forage Crops |
|
|
366 | (5) |
|
1. Digestibility of forage crops depends upon the properties of plant cell walls and is mainly restricted by the lignin content |
|
|
366 | (2) |
|
2. The texture of our fruits and vegetables depends to a large extent on the properties of their cell walls |
|
|
368 | (1) |
|
3. Gurns, water-soluble cell wall-associated polymers, are used to stabilize emulsions and to modify the texture of processed foods and other industrial products |
|
|
369 | (1) |
|
4. Pectins are used as thickeners, texturizers, stabilizers, and emulsifiers in the food and pharmaceutical industries |
|
|
370 | (1) |
|
B. Medicinal and Physiological Properties of Cell Wall Molecules |
|
|
371 | (7) |
|
1. Dietary fiber in the human diet is a residual component of plant cell walls |
|
|
371 | (1) |
|
2. The consumption of dietary fiber has been associated with benefits in human health |
|
|
372 | (2) |
|
3. Gurn arabic and pectins soothe irritated or inflamed mucosal tissues |
|
|
374 | (1) |
|
4. Pectic polysaccharides from medicinal plants stimulate the immune system via Peyer's patch cells in the intestine |
|
|
374 | (1) |
|
5. Bioactive pectins from some medicinal herbs promote the proliferation of immune system cells and their activities |
|
|
375 | (1) |
|
6. Bioactive pectins inhibit tumor growth by inducing cancer cell apoptosis |
|
|
376 | (1) |
|
7. Coating of medical devices with cell wall polysaccharides alters their bioactive properties |
|
|
377 | (1) |
|
C. Cell Wall Fibers Used in Textiles |
|
|
378 | (6) |
|
1. Commercially important plant fibers are derived from many types of plants and possess physical properties that are exploited in textile products |
|
|
378 | (1) |
|
2. Cotton is the most widely used plant textile fiber |
|
|
378 | (2) |
|
3. Cotton fibers are epidermal trichomes that develop on the surface of ovules |
|
|
380 | (1) |
|
4. Coconut-derived coir fibers are used extensively in tropical countries |
|
|
381 | (1) |
|
5. The physical properties of different bast fibers make them suitable for use in specialized types of textiles |
|
|
381 | (2) |
|
6. Leaf fibers are used for ropes, tea bags, currency paper, and filter-tipped cigarettes |
|
|
383 | (1) |
|
D. Wood: an Essential Product for Construction and Paper Production |
|
|
384 | (7) |
|
1. Wood is one of the world's most abundant industrial raw materials |
|
|
384 | (1) |
|
2. Wood and paper properties are derived from the composition and morphology of the xylem cell walls |
|
|
385 | (2) |
|
3. The physical strength of wood depends on the multilayered structure of the wood cell walls and cell morphology |
|
|
387 | (2) |
|
4. Cell wall-degrading enzymes are increasingly used for pulp and paper processing for environmental and economic reasons |
|
|
389 | (1) |
|
5. Bark is a source of cork, tannins, waxes, and drugs |
|
|
390 | (1) |
|
E. Plant Cell Walls: the Most Important Renewable Source of Biofuels and Chemical Feedstocks |
|
|
391 | (16) |
|
1. Humankind's survival may depend on the wise use of renewable natural resources |
|
|
391 | (3) |
|
2. Plant cell walls and their derivatives comprise a major fraction of the terrestrial biomass and carbon content |
|
|
394 | (1) |
|
3. Photosynthesis-driven biomass production by plants constitutes a major and sustainable energy source |
|
|
395 | (1) |
|
4. Half of the wood harvested around the world is burnt as fuel |
|
|
396 | (1) |
|
5. Producing bioethanol from lignocellulosic biomass at competitive prices will require significant investments in research |
|
|
396 | (2) |
|
6. Overcoming the lignin barrier is essential to the success of the lignocellulosic biomass-based liquid biofuel industry |
|
|
398 | (2) |
|
7. Major improvements in fermenting enzyme systems are needed to improve the efficiency of ethanol production |
|
|
400 | (1) |
|
8. New types of biorefineries are needed to produce ethanol from lignocellulosic biomass at increased efficiencies and lower cost |
|
|
400 | (2) |
|
9. Plant cell walls are a renewable source of industrial chemicals |
|
|
402 | (2) |
|
10. Large-scale biofuel and chemical feedstock production is likely to affect food prices and biodiversity |
|
|
404 | (1) |
|
11. Cell walls offer unique challenges and opportunities for genetic engineering |
|
|
405 | (2) |
|
|
|
407 | (1) |
|
|
|
407 | |
Lisainfo e-raamatute kohta