If you leave a vegetable in the refrigerator too long it getsmushy.

Explain why on a molecular level.

Constituent Features

Pectic polysaccharides Make up 34% of the cell wall material and are located in the middle lamella of the primary cell wall

Ramnogalacturonano I It constitutes 7% of the primary cell wall. It is the region of pectin whose estimated polymerization degree is 2000, linked by links to (1-4) and whose sequence of galacturonic acid units is interrupted by ramnoside residues and has neutral sugars adjacent to the chain.

Homogalacturonano Portion of pectic polysaccharide that forms 6% of the cell wall and contains branched regions of

galacturonosyl residues with bonds to (1-4); it is linked to ramnogalacturonan also

it considers within the homogalacturonanos the regions of pectin stable to the hydrolysis of endopoligalacturonasas.

Ramnogalacturonano II Forms 3% of the primary cell wall and constitutes a small region of the pectic polysaccharides

formed of 25-50 glycosyl residues and by monosaccharides that are rarely observed in other polymers, for example: 2-O-methyl-D-xylose and D-apiosa. Ramnogalacturonano II contains as terminal residues galacturonic acid, D-galactose, L-arabinose, L-rhamnose, 2-O-methyl-L-fucose and 2-O-methylD-xylose.

Arabinanos It forms 9% of the primary cell wall of dicotyledonous plants and are branched chain regions in bonds to (1-5), which shows different degrees of polymerization, depending on the vegetable.

It contains ligatures with various residues that involve bonds (1-5), (3-5), (2-5) and (2,3-5).

Galactans Together with arabinogalactans, it represents approximately 9% of the cell wall. Contains ligatures b (1-4) and a (1-6) between galacturonic acid monomers. It also has regions of galactosyl linked by links to (1-6).

Arabinogalactans Galactose and arabinose units linked by ligatures b (1-3) and b (1-6); It also presents itself as

a constituent of pectic substances.

Cellulose Glucose units linked by b links (1-4). Polymer of more than 12,000 glucose monomers that

it presents crystalline regions in which the molecules are arranged in fibrils, where groups in

parallel form packages; they are likely to interact with other constituents of the cell wall.

Hemicellulose and Polymer Xylanes of 150-200 units of xylose linked by b links (1-4); they also contain uronic acid

probably acetylated.

Lignin High molecular weight insoluble polymer of coumaryl, coniferyl and synapyl alcohols. It contains 100 or more aromatic units high in methoxy groups that penetrate the cell wall, producing

secondary thickening and act as a hydrophobic filler; they form covalent ligatures with

carbohydrates from the wall.

Proteins Hydroxyproline-rich proteins are found in the cell wall. Basically they are several glycosidic esters and Schiff bases bound to polysaccharides; Hydroxyquinone chelate bridges with lignin.