Key difference - aldose vs. ketosis
In chemistry, “-ose” at the end of a chemical term generally refers to a sugar compound. Hence, both aldoses and ketoses are groups of chemical compounds that are sugars; More precisely, they are " monosaccharides ". Sugars can consist of individual repeating units or of multiple units. The sugars made from individual repeating units are called monosaccharides, and when they consist of two subunits they are also called "disaccharides". Therefore, aldoses are monosaccharides with aldehyde groups at the end of the carbon chain, while ketoses are monosaccharides that contain ketone groups in the carbon chain . This is the main difference between aldose and ketosis. In general, both aldoses and ketoses can be referred to as monosaccharides.
What is Aldose?
This is a type of monosaccharide that contains an aldehyde group on its carbon backbone . Generally there is one aldehyde group per monosaccharide molecule. The aldehyde group is a reactive chemical group referred to as (-CH = O). The simplest form of the aldose would be a sugar molecule with two carbon atoms, one of which contains the aldehyde group. The chemical formula of Aldose is written as C n (H 2 O) n .
Aldoses usually contain asymmetric carbon centers (with four different types of systems attached to the carbon center under consideration). Therefore, it is believed that an aldose having at least three carbon atoms has a stereogenic center that exhibits optical activity. In addition, aldoses can be divided into two groups; D-aldose and L-aldose , depending on their type of chiral activity. When the structure of an aldose is drawn in open form, it is called a "Fischer projection". When we mark an aldose as either D or L, we are looking at the chirality of the second most distant carbon atom from the position of the aldehyde group. If the alcohol group (-OH) is on the right hand side of the Fischer projection it is categorized as D-aldose and if the alcohol group is on the left hand side of the Fischer projection it is categorized as L-aldose. In general, biological receptors are more sensitive to D-aldoses than L-aldoses. Can be distinguished by the Seliwanoff test ketoses aldoses. Aldoses are slow to react and produce a light pink color. Glucose, galactose, and ribose are some well-known aldoses.
What is ketosis?
Ketose is a monosaccharide in which the carbon backbone contains a ketone group . In general there would be one ketone group per sugar molecule. The ketone group is a reactive chemical group called (-C = O). The simplest form of ketosis is the sugar molecule made up of three carbon atoms, the middle one with the ketone group. Just like aldoses, ketoses have many stereogenic centers within the carbon chain.
Ketoses are also often drawn in their Fischer projection. Ketoses can be differentiated from aldoses by the Seliwanoff test. Here the ketosis reacts with resorcinol to a deep cherry red color. Fructose, ribulose, and erythrulose are some commonly known ketoses .
Difference Between Aldose and Ketosis
Aldoses are monosaccharides that contain one aldehyde group per molecule.
Ketoses are monosaccharides that contain one ketone group per molecule.
Aldoses tend to isomerize into ketoses.
Ketoses can isomerize to aldoses only if the carbonyl group is at the end of the chain. And they are known as "reducing sugars".
Aldoses are slow to react and produce a light pink color.
Ketoses react with resorcinol to give a deep cherry red color.
"Aldose" by Rob Hooft - own work (Original text: own work by Rob Hooft). (Public Domain) via Wikimedia Commons
"Skeletal Structure of Ketosis". (CC BY-SA 3.0) via Wikimedia Commons