Monosaccharide Study Notes

Monosaccharide Monosaccharide means a sugar which is called a simple sugar because it can no longer be hydrolyzed86 . Monosaccharides dissolve in water and taste sweet thats why they are also called sugar. Chemical names always end in -ose. In Nutrition Science there are only three types of monosaccharides that are important namely glucose, fructose and galactose. Monosaccharides are the simplest carbohydrate units with the formula CnH2nOn where n = 3 – 8. Monosaccharides, often called simple sugars, are carbohydrates that cannot be hydrolyzed into simpler forms. Monosaccharides can be grouped based on their carbon atom content, namely triose, tetrose, pentose, and hexose or heptose.Monosaccharides or simple sugars consist of only one polyhydroxyaldehyde or ketone unit or only one saccharide molecule. The monosaccharide framework is an unbranched single-bonded carbon chain. Glucose Glucose is found in the bloodstream (called Blood Sugar Levels) and functions as an energy provider for all cells and body tissues. In physiological conditions, blood sugar levels are around 80-120 mg%. Hyperglycemia is condition where the blood sugar level increase beyond normal and this condition found in people with diabetes mellitus. It contains an aldehyde group and forms a ring structure consisting of 6 atoms and is also called blood sugar because it is found in human blood90 . The main role of glucose body cells is produce energy. Glucose can be oxidized by gentle oxidizing agents such as Tollens' reagent so it is often referred to as reducing sugar. Galactose Galactose is an aldohexose. This monosaccharide rarely occurs free in nature. It generally binds to glucose in the form of lactose, which is the sugar found in milk91. Galactose It has a less sweet taste compared to glucose and is less soluble in water. Like glucose, galactose is also a reducing sugar. Galactose is an aldohexose like glucose which differs in the –OH group on carbon atom number 4 so that it has a cyclic structure almost the same as glucose92 . Galactose can also exist in alpha and beta structures. Fructose Fructose is a hexulose, also called levulose because it rotates the plane of polarization to the left93. It is the only hexulose found in nature. Fructose is the sweetest sugar, found in honey and fruit along with glucose94 . Fructose can be formed from the hydrolysis of a disaccharide called sucrose. Just like glucose, fructose is a reducing sugar. Also called fruit sugar or levulose. It is the sweetest type of saccharide, often found in flower crowns, honey and hydrolysis products from cane sugar. In the body, fructose is obtained from the breakdown of sucrose.