Talk:Monosaccharide

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What are the origins of this word?

Greek mono-, "one", and saccharide, "sugar" (literally "son of sugar" I guess...). —Keenan Pepper 08:49, 13 April 2006 (UTC)[reply]

Have added etymology note. Thanks for pointing out.

Needs some info re them being reducing sugars and also something (at least a link) to/about Benedict's reagent --Bob - 21:36, 11 May 2008 (UTC)-- Agreed, I don't think it needs more than a line but it is needed Jasoninkid (talk) 15:44, 12 May 2011 (UTC)[reply]

Shouldn't the definition of monosaccharide also include the deoxy sugars, such as deoxyribose? Also, can we assume that "carbohydrate" is the same thing as "saccharide"? (In biochemistry they seem to be considered synonymous, but some non-bio chemists apparently consider formaldehyde and glycol aldehyde as "carbohydrates", while no one presumably would include them in the "saccharides". Also in food contexts "carbohydrate" means specifically digestible starches and sugars, excluding e.g. cellulose with is included in "fiber".). All the best, --Jorge Stolfi (talk) 00:00, 22 November 2009 (UTC)[reply]

"Carbohydrate" is not synonymous with "saccharide". Saccharide refers to a monosaccharide, it is usually a single ring (plus 1 possible ligand) which, if opened to a linear form is a carbon chain with all (or most for deoxy-saccharides) of the carbon atoms bonded to a hydroxyl (OH) group and one or two hydrogen atoms. Open chain carbohydrates (such as glycerin) are often not considered saccharides.

In the ring form, each carbon in the ring is a chiral center (the 3-dimensional location of the oxygen link or ligand link is fixed). If the ring is viewed from the edge, the hydroxyl group or ligand is either above or below the ring. Changing the location of these links changes the molecule and its name. For example, d-Glucose (dextrose) is in the hexose family (6 carbon saccharide). D-Glucose is (1R,2S,3R,4R,5S)-2,3,4,5,6-Pentahydroxyhexanal and has 5 chiral centers. Moving the hydroxyl group (or the CH₂OH ligand attached to carbon atom 5) changes the molecule. For this reason, there are 32 hexoses (16 in the dextro form and 16 in the levo form, depending on the location of the ligand). Most animals can metabolize the d-hexoses, but not the l-hexoses.

Saturated linear (open chain) carbohydrates have no chiral centers, so there is only one linear hexose. In the linear form, the carbons are free to rotate. Similarly, in a ring form the ligand is free to rotate so that carbon is not a chiral center. Each double bond or triple bond forms 1 chiral center Drbits (talk) 08:56, 10 August 2016 (UTC)[reply]

I noticed that the lead said some monosaccharides are sweet that implies that some exist salty, bitter, sour, or umami is this really the case? or is the lead misleading?--209.181.16.93 (talk) 19:49, 25 March 2010 (UTC)[reply]

I think the implication is that some monosaccharides are sweet and some have no taste. So I don't think the statement is misleading. Perhaps it can be worded better to avoid confusion though. -- Ed (Edgar181) 23:39, 25 March 2010 (UTC)[reply]

Thanks for the clarification Ed--209.181.16.93 (talk) 20:20, 26 March 2010 (UTC)[reply]

why does the phosphate group attach to C1 carbon of glucose while amino group to C2 carbon?(help)Ranjitr303 (talk) 06:22, 26 July 2010 (UTC)[reply]

This is not the right section for this question.

Nitrogen usually attaches directly to another unit, with little space between units. The C1 carbon connects to the Oxygen atom (ether link), which would repel some ligands attached to the Nitrogen atom. Phosphate attaches with an oxygen atom between the phosphorus and each of the units, thus there is over twice the space between the units.

The answer above is prediction using electron orbital proximity. The real answer might be a random selection in the early evolution of life. An example is that all aerobic life uses d glucose for storing energy (instead of some other monosaccharide). Use of other monosaccharides and disaccharides evolved later to protect against other organisms. Another example is that prokaryotic cells use RNA, but the nucleus of eukaryotic cells uses DNA. We could assume that it has to do with control protein attachment or molecular stability, but the answer might be that the nucleus evolved from a random invading unicellular organism that used DNA. On the other hand, when early eukaryotic cells were developing there might have been an RNA lysing enzyme in the invaded cell that prevented invasion by RNA-based cells. Drbits (talk) 11:17, 10 August 2016 (UTC)[reply]

I'm a layman and I can understand much of this article. That means it's well written. Thanks —Preceding unsigned comment added by 76.233.69.52 (talk) 22:48, 24 October 2010 (UTC)[reply]

Just wondering if perhaps the search "CH20" should redirect to Formaldehyde instead of this page, as Formaldehyde is CH20. Thanks 173.66.228.231 (talk) 01:57, 22 November 2010 (UTC)[reply]

CH2O is the empirical formula for monosaccharides so it makes sense to redirect it here. That said there are other compounds that it is also the empirical formula or in the case of formaldehyde molecule formula. A disambiguate may be in order instead of a redirect. Jasoninkid (talk) 15:40, 12 May 2011 (UTC)[reply]

The empirical formula CH₂O is methyl-aldehyde (formaldehyde). Single carbohydrate units are (CH₂O)_nH_m, where n is the number of carbon atoms (2 or more, 6 for normal monosaccharides) and m is 0 for normal ring-form carbohydrates or 2 for linear carbohydrates (such as glycerin). The one carbon carbohydrate would be methanol, which is not usually classified as a carbohydrate.

Polysaccharides have a single oxygen atom connecting the monosaccharides from the removal of a hydrogen from one unit and a hydroxyl unit from the other. Polysaccharides are always ring-form carbohydrates. The empirical formula for normal polysaccharides (chains of hexoses) is (C₆H₁₀O₅)_jH₂O (where j is the number of hexose units and the extra H₂O results from the lack of inter-unit links for the first and last units).

The type of polysaccharide depends on the monosaccharide sequence and the atom number within each unit that attaches to the inter-unit Oxygen atom. Different sequences and linkages can change the solubility, dispersibility, and absorbability (in the digestive system of a specific animal) of the polysaccharide. Branched polysaccharides occur in some forms of cellulose. Drbits (talk) 10:32, 10 August 2016 (UTC)[reply]

For something so fundamental and reoccurring, it's bothering me that all I'm seeing is various facts about classifying monosaccharides and not their behaviors with other molecules. For that reason, this is a horribly written article. X-Fi6 (talk) 02:45, 25 September 2013 (UTC)[reply]

missing good language

Abdullah Al Wasif (talk) 13:15, 11 March 2015 (UTC)[reply]