Monosaccharides (glucose and fructose)

The Mono means one, and the word sackron comes from the Greek language. It means sweet or sugar, or basically, it means “single sugar”. Monosaccharides are the simplest sugar molecules. They can not be broken down into simpler substances. So, these are smaller units, which can still be connected to form large carbohydrates.

Carbohydrates are polyhydroxy aldehydes, which means they have many multiple hydroxyl groups and functional groups, which can be aldehyde or ketone. So Monosaccharides can also be categorized based on the presence of aldehyde as well as ketone.

About 20 monosaccharides are known to occur in nature. Some common examples are glucose, fructose, ribose, etc.

Monosaccharides

 Monosaccharides are a simple form of carbohydrates. Most organisms harvest and store energy by breaking down glucose’s monosaccharides and producing the energy released. Monosaccharides are molecules with more than one hydroxyl group (-OH), and a carbonyl group (C=O) either at the terminal carbon atom(aldose) or at the second carbon atom (ketose). The general formula of Monosaccharides is neither Cn(H2O)nor CnH2nOn. Monosaccharides with 3, 4, 5, 6, and 7 carbon atoms are called trioses, tetroses, pentoses, hexoses, heptose, as well as aldose or ketosis, depending on whether they contain aldehyde or ketone groups.

Monosaccharides are classified based on the number of carbon atoms and functional groups present in them.

• Dioses, a two-carbon monosaccharide
• Trioses, a three-carbon monosaccharide

Exp-Glyceraldehyde and dihydroxyacetone

• Tetroses – a four-carbon monosaccharide

Exp-D-erythrose, D-threose, and D-erythrulose

• Pentoses – a five-carbon monosaccharide

Exp-Ribose in RNA and deoxyribose in DNA

• Hexoses – a six-carbon monosaccharide

Exp-Glucose, Galactose, Mannose, and Fructose

• Heptoses – a seven carbon monosaccharide

Exp- L-glycero-D-manno-heptose

Aldoses 

Monosaccharides have an aldehyde group (-CHO) as a functional group. Aldehyde group is present at the terminal carbon or C-1. An example of the aldehyde group, which is aldose, is glucose.

Ketose

Monosaccharides have a ketonic group (-C=O) and a keto group present at middle carbon or C-2.

An example of ketosis is fructose.

Structure of Monosaccharides

Monosaccharides have the same general formula as (CH2O)n, a central carbon molecule linked to two hydrogens and one oxygen. The Oxygen will bond to hydrogen, producing a hydroxyl group.

As we know that carbon can form 4 bonds, several carbon molecules can bond together. One of the carbons in the chain forms a double bond with oxygen which is called a carbonyl group.

Examples of Monosaccharides are Glucose, Fructose, and Galactose.

If this carbonyl group occurs at the end of the chain, the monosaccharides are in the aldose family. If the carbonyl group is in the middle of the chain, the monosaccharides are in the ketose.  

Properties of Monosaccharides

Maximum monosaccharides have a sweet taste (fructose is sweetest;73% sweeter than sucrose). Monosaccharides Stays solid at room temperature and extremely solvable in water

Glucose

As one group of monosaccharides, glucose is called dextrose. Glucose happens in both joints and in the free state in nature. The Greek word glucose means “sweet”. The molecular formula glucose is C6H12O6. It is found in fruits, and honey is responsible for circulating free sugar in the blood of higher animals. Glucose is a source of energy in cell function.

Glucose is responsible for the regulation of its metabolism is of great importance.

Molecules of starch, the major energy-reserve carbohydrates of plants, consist of thousands of linear glucose limits. In nature, glucose occurs freely and in combined form. Glucose is present in sweet fruits and honey as well. Grapes contain glucose in big amounts.

Preparation of Glucose

From starch, commercially glucose is acquired through hydrolysis of starch through boiling it with dilute H2SO4 at 393k below pressure.

From sugar(cane sugar) : If sucrose is boiled with dilute HCL or H2SO4 in an alcoholic solution, glucose and fructose are acquired in an identical amount

Structure of Glucose

Glucose is aldohexose and is also known as dextrose. Glucose can be called aldohexose and dextrose. It is a monomer of many important compounds such as carbohydrates, starch, and cellulose. Globally, these are the most common organic compounds.

Use of Glucose

• Used to treat hypoglycemia (low blood sugar)
• It is given to patients who are very sick and unable to eat as it provides calories and carbohydrates.
• It is used to treat an increase in potassium levels in the blood (hyperkalemia).
• It is used as a precursor to composites.   

Fructose 

French chemist Augustin-Pierre Debrunfaut discovered fruit sugar. Sugar is found in trees, honey, flowers, and many root vegetables. It is usually mixed with sucrose to make a disaccharide. Commercially derived from sugar, sugarcane, and other products. But if taken in excess, it can cause obesity or even insulin resistance, to name a few. Fructose is an important ketohexose.It is acquired along with glucose by the hydrolysis of disaccharides and sucrose. As a natural monosaccharide, it is found in fruits, honey, and vegetables. In its clean form, it is used as a sweet. It is also an important ketohexose.

 Structure of Fructose

Fructose also has the molecular formula of C6H12O6 and based on its reactions, it was found to contain a ketone functional group at carbon number 2 and six carbons in the chain as in the case of glucose.

It belongs to the D-series and is a levorotatory compound.

Uses of Fructose

• Crystalline fructose is used to enhance the flavor in the food industry.
• It is used in spicy water, energy drinks, low-calorie products, etc.
• Fruit sugar is used in the production of soft, juicy cookies, restaurants, reduced-calorie products, etc.

Galactose 

Galactose is manufactured by mammals in the form of milk. Lactose holds a lot of energy in its bonds, and for breaking down the bonds separately, definite enzymes are developed by the offspring of mammals. Galactose, when joined with glucose (monosaccharide), through a condensation reaction, the final result is the disaccharide lactose. The hydrolysis of lactose to glucose and galactose is catalyzed by the enzymes lactase and β-galactosidase.

Conclusion

The monosaccharides are used to produce and retain energy. Much of organic matter generates energy by breaking down monosaccharide glucose and collecting the energy released by bonds. Some monosaccharides are used to make long strands, which can be used as cellular structure. They make up the bulk of our diet. Honey has long been used as an immediate source of energy in the ayurvedic medical system.

From cellulose in the form of wood, We build furniture and coat in cellulose in the form of cotton fiber. For textiles, paper, lacquers, and breweries industries, they are important to supply materials.  First and foremost, monosaccharides are used to produce and store energy. Much organic matter generates energy by breaking down monosaccharide glucose, and harvesting energy released from bonds. Some monosaccharides are used to make long strands, which can be used as a cell structure