Editing Sugar (section)

=== Natural polymers ===

[[Biopolymer]]s of sugars are common in nature. Through photosynthesis, plants produce [[glyceraldehyde-3-phosphate]] (G3P), a phosphated 3-carbon sugar that is used by the cell to make monosaccharides such as glucose ({{chem|C|6|H|12|O|6}}) or (as in cane and beet) sucrose ({{chem|C|12|H|22|O|11}}). Monosaccharides may be further converted into [[polysaccharides#Structural polysaccharides|structural polysaccharides]] such as [[cellulose]] and [[pectin]] for [[cell wall]] construction or into energy reserves in the form of [[polysaccharides#Storage polysaccharides|storage polysaccharides]] such as starch or [[inulin]]. Starch, consisting of two different polymers of glucose, is a readily degradable form of chemical [[potential energy|energy]] stored by [[cell (biology)|cells]], and can be converted to other types of energy.<ref name=Pigman/> Another polymer of glucose is cellulose, which is a linear chain composed of several hundred or thousand glucose units. It is used by plants as a structural component in their cell walls. Humans can digest cellulose only to a very limited extent, though [[ruminant]]s can do so with the help of [[Symbiosis|symbiotic]] bacteria in their gut.<ref>{{cite journal |doi=10.1007/BF01089198 |last1=Joshi |first1=S |last2=Agte |first2=V |title=Digestibility of dietary fiber components in vegetarian men |journal=Plant Foods for Human Nutrition (Dordrecht, Netherlands) |volume=48 |issue=1 |pages=39–44 |year=1995 |pmid=8719737|s2cid=25995873 }}</ref> [[DNA]] and [[RNA]] are built up of the monosaccharides [[deoxyribose]] and [[ribose]], respectively. Deoxyribose has the formula {{chem|C|5|H|10|O|4}} and ribose the formula {{chem|C|5|H|10|O|5}}.<ref>{{Merck11th|8205}}.</ref>