Simple monosaccharides have a linear and unbranched carbon skeleton with one carbonyl (C=O) functional group, and one hydroxyl (OH) group on each of the remaining carbon atoms
The carbonyl group is placed at the beginning of the saccharide. If the carbonyl group is an aldehyde (more common in carbohydrates), then the monosaccharide is an aldose, and if the carbonyl group is a ketone, then the monosaccharide is a ketose. This sugar has an aldehyde functional This sugar has a ketone functional group so it is an aldose. group so it is a ketose.  Monosaccharides are classified as well based on their functional groups. A functional group is categorized by atoms or bonds that are responsible for the chemical reactivity within a molecule. If a monosaccharide contains a ketone group in an inner atom, then the monosaccharide is classified as a ketose. A ketone group is a carbon atom forming a double bond with oxygen and single bonds with two hydrocarbon groups. A hydrocarbon group is a group that contains carbon bonded with hydrogen Classification [edit]. Monosaccharides are the simplest form of carbohydrates and may be subcategorized as aldoses or ketoses. The sugar is an aldose if it contains an aldehyde functional group. A ketose signifies that the sugar contains a ketone functional group. Tetroses are monosaccharides with four carbon atoms. An aldotetrose has an aldehyde functional group at carbon number one. The two common types of aldotetroses are D-Erythose and D-Threose. The D configuration is more favor. Simple monosaccharides have a linear and unbranched carbon skeleton with one carbonyl (C=O) functional group, and one hydroxyl (OH) group on each of the remaining carbon atoms. Further, each carbon atom that supports a hydroxyl group (so, all of the carbons except for the primary and terminal carbon) is chiral, giving rise to a number of isomeric forms, all with the same chemical formula. Tetrose. A tetrose is a monosaccharide with 4 carbon atoms. They have either an aldehyde functional group in position 1 (aldotetroses) or a ketone functional group in position 2 (ketotetroses).The aldotetroses have two chiral centers (asymmetric carbon atoms) and so 4 different stereoisomers are possible. Monosaccharides can be linked together into what are called polysaccharides (or oligosaccharides) in a large variety of ways. Many carbohydrates contain one or more modified monosaccharide units that have had one or more groups replaced or removed. Attached to all straight chain forms of monosaccharides are side  groups. The side groups are one carbonyl functional group and one  hydroxyl group on the remaining carbon a … toms. 1 Functional Groups: Organic Chemistry 101 Functional groups are groups of atoms that are found in molecules, which are involved in the chemical reactions associated with those molecules. 2  Functional groups can be iden…. 3  Information About the Alcohol Functional Group Functional groups are an integral part of chemistry. Monosaccharides consist of a carbon chain of three or more carbon atoms containing a hydroxyl group attached to every carbon except one. The lone carbon atom is double-bonded to an oxygen atom, and this carbonyl group may be in any position along the carbon chain. Biomolecules meet specific structural criteria to be classified as carbohydrates. Simple carbohydrates are modifications of short hydrocarbon chains. Several hydroxyls and one carbonyl functional group modify these hydrocarbon chains to create a monosaccharide, the base unit of all carbohydrates. Those monosaccharides that contain an aldehyde functional group are called aldosesA monosaccharide that contains an aldehyde functional group. ; those containing a ketone functional group on the second carbon atom are ketosesA monosaccharide that contains a ketone functional group on the second carbon atom. . 
http://www.chem.ucla.edu/harding/ec_tutorials/tutorial55.pdf http://study.com/academy/lesson/monosaccharides-definition-structure-examples.html https://en.wikibooks.org/wiki/Structural_Biochemistry/Carbohydrates/Monosaccharides https://en.wikipedia.org/wiki/Monosaccharide https://en.wikibooks.org/wiki/Principles_of_Biochemistry/The_Carbohydrates:_Monosaccharides,_Disaccharides_and_Polysaccharides http://www.answers.com/Q/What_two_functional_groups_are_found_in_all_monosaccharides https://dlc.dcccd.edu/biology1-3/carbohydrates http://2012books.lardbucket.org/books/introduction-to-chemistry-general-organic-and-biological/s19-02-classes-of-monosaccharides.html
what functional groups are in all monosaccharides