Difference Between Aldose and Ketose

Main Difference

Carbohydrates are the one of the most abundant type of organic compounds on the earth, which are rich source of energy for living. It is one of the macronutrients required by the human for living, which means that it is required by human in the large amounts in daily diet. Aldose and Ketose sugars are the carbohydrate molecules that can easily be distinguished from one and another with respect to their properties and formation. These carbohydrates are made up similar repetitive single units or they are made up of more than one unit or monomer. Following it there are two types of carbohydrates, simple carbohydrates and complex carbohydrates. Simple carbohydrates contains only or two sugar units, therefore monosaccharaides (containing one sugar unit) and disaccharides (containing two sugar units) are simple carbohydrates. On the other hand, complex carbohydrates contain polymers (many units or monomers) of sugar units and they are called polysaccharides. Both, aldose and ketose are monosaccharides that can be differentiated as aldose is the monosaccharide that contains aldehyde group in its structure along with the carbon chain, whereas ketose is the monosaccharide that contains ketone group along with the carbon chain.

Comparison Chart

AldoseKetose
StructureAldose is the monosaccharide that contains aldehyde group in its structure along with the carbon chain.Ketose is the monosaccharide that contains ketone group along with the carbon chain.
Seliwanoff’s TestAldose reacts in slow pace and produces the light pink color.Ketose reacts with the crystalline compounds named resorcinol and produces a dark reddish color.
ExampleGlycolaldehyde, glyceraldehyde, erythrose, threose.Fructose, ribulose and xylulose, erythrulose, tagatose, sorbose.

What is Aldose?

Aldose is the monosaccharide (carbohydrate molecule) that contains aldehyde group in its structure at the end of carbon chain. The chemical formula of aldose is Cn(H2O)n. The aldehyde functional group in the organic chemistry stands for the presence of a carbon atom that is single bonded to a hydrogen atom, and is double bonded to an oxygen atom. The simplest aldose is the diose glycolaldehyde as it contains the two carbon atoms along with the aldehyde group. Glycolaldehyde, glyceraldehyde, erythrose, threose, ribose, arabinose, xylose, lyxose, allose, altrose, glucose, mannose, gulose, idose, talose, and galactose are the examples aldose that contains one group of aldehyde. The above mentioned sugar carbohydrates play pivotal role in various functions of the livings. Aldoses and ketoses can be distinguished from one and another using the Seliwanoff’s test as aldose reacts in slow pace and produces the light pink color, whereas ketose reacts with the crystalline compounds named resorcinol and produces a dark reddish color. One of the main differences between aldose and ketose is that the carbonyl group in aldose is present in the end of the carbon chain, while carbonyl group in ketose is present in the middle of the carbon chain.

What is Ketose?

Ketose is the monosaccharide (carbohydrate molecule) that contains ketone group along with the carbon chain in its structure. The simplest example of a ketose is dihydroxyacetone, which is a three-carbon structure containing one keto group and two hydroxyl groups in its structure. Aldoses and ketoses can be distinguished from one and another using the Seliwanoff’s test as aldose reacts in slow pace and produces the light pink color, whereas ketose reacts with the crystalline compounds named resorcinol and produces a dark reddish color. As the molecular formula of ketone is RCOR, in this a carbonyl group (CO) is attached to an R group. Fructose, ribulose and xylulose, erythrulose, tagatose, sorbose, psicose are some of the prominent examples of ketose sugars. A reducing sugar is the sugar that can act as reducing agent as it has a free aldehyde group or a free ketone group. With such type of sugars ketoses can isomerize into an aldose when carbonyl group is present at the last of the molecule.

Key Differences

  1. Aldose is the monosaccharide that contains aldehyde group in its structure along with the carbon chain, whereas ketose is the monosaccharide that contains ketone group along with the carbon chain.
  2. Aldoses and ketoses can be distinguished from one and another using the Seliwanoff’s test as aldose reacts in slow pace and produces the light pink color, whereas ketose reacts with the crystalline compounds named resorcinol and produces a dark reddish color.
  3. A reducing sugar is the sugar that can act as reducing agent as it has a free aldehyde group or a free ketone group. With such type of sugars ketoses can isomerize into an aldose when carbonyl group is present at the last of the molecule.
  4. Aldose will get outlined as a result of the monosaccharide that solely has one aldehyde group in each molecule and turns right into a pure sugar. On the other hand, Ketose will get outlined as a monosaccharide that has a ketone group in each molecule that includes three carbon atoms.
  5. The best occasion of such aldose building turns into glycolaldehyde that solely has one carbon atom inside its building. On the other hand, the right occasion of a ketose building turns into dihydroxyacetone, and it does not have any optical train.
  6. Examples of aldose embody glycolaldehyde, glyceraldehyde, erythrose, threose, ribose, arabinose, xylose, lyxose, allose, altrose, glucose, mannose, gulose, idose, talose, and galactose.
  7. Fructose, ribulose, and xylulose are the three important examples of ketose sugars. Other examples embody erythrulose, tagatose, sorbose, psicose and dihydroxyacetone even supposing the ultimate one may not get categorized as a ketose.
  8. An aldose would possibly decompose into ketose counting on the isomerization response. On the other hand, ketose would possibly decompose into aldose supplied that there exists a separate carbonyl group on the end of each atom.
  9. In Seliwanoff’s check out aldoses generally tend to answer at a common tempo, and ship a lightweight pink shading, nonetheless, ketoses meet with resorcinol to create a darkish pink shading.

Comparison Video

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Aimie Carlson

Aimie Carlson is an English language enthusiast who loves writing and has a master degree in English literature. Follow her on Twitter at @AimieCarlson

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