Ketose A monosaccharide that contains

Ketose A monosaccharide that contains a ketone group. 

Haworth structure The ring structure of a monosaccharide, ketose A monosaccharide that contains a ketone group, lactose A disaccharide consisting of glucose and galactose found in milk and mUk products. 

Monosaccharides containing three-, four-, five-, and six-carbon atoms are called trios-es, tetroses, pentoses, and hexoses, respectively. Monosaccharides that contain an aldehyde group on one carbon atom and a hydroxyl group on each of the other carbon atoms are called aldoses. Ketoses are monosaccharides that contain a ketone group on one carbon atom and a hydroxyl group on each of the other carbons. 

Monosaccharides that contain an aldehyde group are called aldoses, whereas those containing a ketone group are ketoses. Monosaccharides are also classified by the number of carbon atoms as trioses, tetroses, etc. objective 5 (Section 7.4), Exercise 7.22. Most natural monosaccharides belong to the d family. 

Carbohydrates are polyhydroxy aldehydes and ketones that are commonly known as sugars. A monosaccharide is a carbohydrate composed of one sugar unit and a disaccharide is a carbohydrate composed of two monosaccharide units. An oligosaccharide is composed of 2-10 monosaccharide units a polysaccharide is composed of 10 or more monosaccharide units. An aldose is a carbohydrate that contains an aldehyde unit and a ketose is a carbohydrate that contains a ketone unit. Monosaccharides are categorized by the total number of carbons in the structure triose, tetrose, pentose, hexose, etc. The d and 1 configurations of a monosaccharide are based on the Fischer projection of d-glyceraldehyde. A Fischer projection is an older representation of sugars. 

We will examine the products that would result from cleaving of all the possible combinations of bonds in a monosaccharide. We will do so by considering various subunits of the structme. However, all the subunits react, so we must analyze all carbon-carbon bonds and the attached functional groups to determine the products that can form. First, consider the subunit that contains a primary hydroxyl group. This structural feature exists at the highest numbered carbon atom of an aldose. The unit also occurs at C-1 and the highest numbered carbon atom of a ketose. 

Although the early studies established the relationships and properties of the classic families of aldoses and ketoses, and their simple derivatives, some unusual monosaccharide structures were later encountered that were of importance in the biomedical area. The antiscorbutic vitamin isolated from paprika in 1928 by Szent-Gyorgi (40) and initially termed hexuronic acid was subsequently shown to be a six-carbon furanose lactone containing an enediol structure (Scheme 10)... 

The name carbohydrates comes from their composition which is represented by the general formula C (H20) which resembles the combination of carbon and water. This composition implies that a molecule of monosaccharide consists of a hydrocarbon chain with attached hydroxyl groups. More detailed analysis shows that most of the monosaccharide molecules have hydrocarbon chains which are from five to seven carbon atoms long. From the study of the chemical behavior of different monosaccharides it follows that some of them exhibit reactions typical for aldehydes and others show reactions typical for ketones. The monosaccharides can therefore be classified into two groups aldoses and ketoses. In their nomenclature, the names of carbohydrates are formed from the root based on the number of C-atoms, the fundamental functional group (ketone or aldehyde) and the suffix -ose. While the aldehyde group always contains the first carbon atom of the chain, keto-group in all known carbohydrates appears at the second carbon atom of the chain. Some monosaccharides named in accordance with these rules are represented in the scheme below. 

Monosaccharides have the general formula C H2 0 , with one of the carbons being the carbonyl group of either an aldehyde or a ketone. The most common monosaccharides have from three to nine carbon atoms. The suffix indicates that a molecule is a carbohydrate, and the prefixes trir, tetr-, pent-, and so forth, indicate the number of carbon atoms in the chain. Monosaccharides containing an aldehyde group are classified as aldoses those containing a ketone group are classified as ketoses. 

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