What Are Monomers Of Carbohydrates?

Monomers are simple sugars and the fundamental building blocks for carbohydrates, often referred to as monosaccharides and utilized to store and generate energy by living cells.

What is the structure of monosaccharides? How do cells utilize energy for them?

Defining Monosaccharides

Let’s take a minute to define them before going into the deeper intricacies of monosaccharides. A monosaccharide is simple sugar, which are also the fundamental units of carbohydrates or building blocks. Monosaccharides are types of monomers, molecules able to combine to build more complex polymers with other similar molecules.

A monosaccharide’s usual chemical formula is CnH2nOn. In other words, both hydroxyl (OH) and carbonyl (C=O) are produced from one hydroxy group. There are several types of monosaccharides characterized by the number of carbon atoms in the molecule. A diosis molecule contains two carbon atoms, three trioses, four tetrosis. Fructose (six carbons) and fructose are some of the main monosaccharides (also six-carbon).

Monosaccharides bind each other to form carbohydrates, known as polysaccharides or oligosaccharides. It’s termed a disaccharide if an oligosaccharide contains only two monosaccharides. The combination of over 20 monosaccharides produces a complex polysaccharide.

The Function of Monosaccharides

In cells of animals and plants, monosaccharides perform a variety of functions. Monosaccharides’ purpose is to store energy and generate energy. Most organisms get their power from the breaking down of glucose monosaccharide and from the energy produced by glucose chemical bonds.

Some monosaccharides are utilized to produce fibers that form different cell architectures. The production of cellulose by plants is one example of this process. Some types of bacteria can also build a cell wall of a different polysaccharide type. The animal cells are likewise enclosed in a polysaccharides structure which, as previously mentioned, comes from smaller monosaccharides.

Monosaccharides do not need absorption or intestinal processing, while oligosaccharides must first be digested into monosaccharides before they can be absorbed.

The Monosaccharide Structure

Out of the hydroxyl groups and the carbonyl groups, monosaccharides are formed. The carbonyl group consists of carbons that may create up to four bonds. These carbon molecules link together in different ways, and a twofold connection to an oxygen atom forms one of the carbons in the carbon chain. The existence of this double bond of carbon-oxygen forms the carbonyl group. Note that when at the end of the chain the carbonyl group is present, it indicates the monosaccharide belongs in the aldose family. If there is a double carbon-oxygen present in the center of the chain, then monosaccharide is part of the ketose family.

The structural isomers are recognized as molecules that have identical formulae but have distinct structures. Meanwhile, in a three-dimensional space isomeric molecules which have both the same chemical formula and the same order of linked atoms are called stereoisomers.

Eight or more carbon molecules of monosaccharides are uncommon since they are very unstable and break down quite rapidly.

Important Monosaccharides

Three of the main monosaccharides include glucose, fructose and galactose sugars. Each monosaccharide has the same chemical formulation: C6H12O6. The fact that all three common sugars have six carbon atoms implies all hexose molecules. Each sugar has a distinct atomic configuration, but the same chemical formula is present in the three sugars.


Glucose is a monosaccharide that supplies organisms with both structure and energy. The process of glycolysis breaks down the glucose molecules, creating energy as well as chemical precursors needed in cellular respiration. If a cell has all its energy, the cell may store extra glucose for later use. Glucose is stored in combination with monosaccharides, and some plants produce long glucose chains Called starch. This starch is then dismantled when the plant requires energy. Animals have a similar storage mechanism, which stores glucose like glucose polysaccharide.


Galactose, but primarily mammals, is generated by many different species. Animals are galactose in their milk, and they are saved for energy when young mammals consume milk. Galactose is often coupled with glucose to produce a disaccharide called lactose. Lactose may contain a significant amount of energy, and young animals develop specific enzymes for breaking down lactose connections. When an animal is weaned from its mother’s milk, the synthesis of enzymes that break down glucose and galactose progressively starts to stop.

Human beings are the only animal which continues to consume milk in maturity, resulting in human species having enzymes which continue to break down lactose throughout life. Lactose-intolerant individuals have difficulties digesting lactose correctly in milk because they lack enzymes.


Fructose is quite similar to glucose, but its structure is different. At the end of the molecule, whereas glucose has a carbonyl group, fructose has a carbonyl group in the middle part of the chain. Like glucose, fructose contains six hydroxyl carbons linked to it. Fructose is metabolized differently than glucose because it has a distinct ring structure. To break them down, various monosaccharides require different enzymes. Fructose may be mixed with other monosaccharides, like other monosaccharides. When fructose mixes, oligosaccharides are created. An example is sucrose, consisting of a fructose molecule linked to a glucose molecule.

There are exceptions to general rule that monosaccharides follow as CnH2nOn formula. One exception is the monosaccharide Deoxyribose, which has the chemical formula: H−(C=O)−(CH2)−(CHOH)3−H

2-deoxyribose has a vital biological function, since it is part of the deoxyribonucleic acid (DNA) molecule, the building blocks of life.

Read More:

Leave a Comment