STRUCTURE OF CARBOHYDRATES

Carbohydrates are chemical molecules composed only of Carbon (C), Hydrogen (H), and Oxygen (O). They’re made up of a carbon chain, an aldehyde or ketone, and hydroxyl groups. Every carbon atom has one oxygen atom bonded to it. There are thousands of distinct carbohydrates, but they all contain one or more monosaccharides, which are smaller units.

CARBOHYDRATES

A macromolecule made up of the elements carbon, hydrogen, and oxygen is referred to as a carbohydrate. Carbohydrates are mostly used in the body to provide fast energy. Simple carbs, which have a 1 or 2 ring structure, and the complex carbohydrates, that have a structure with multiple singed sugars, are the two basic forms of carbohydrates.

Examples of Carbohydrate

1. Glucose

2. Sucrose

3. Glycogen

4. Fructose

5. Starch

6. Lactose

7. Cellulose

Structure of Carbohydrates 

Carbohydrates have been defined as substances with the empirical formula Cn(H2O)m. However, a carbohydrate is normally described as the polyhydroxy ketone or polyhydroxy aldehyde with the conventional formula, a molecule nearly comparable to it, or oligomers or polymers of these molecules. They require a different set of skills to manage than classic “natural products” such as steroids, terpenes, and alkaloids since they are water – soluble and difficult to crystallise.

A monosaccharide is derivative of a carbohydrate having a single carbon chain.

Disaccharide and trisaccharide are carbohydrate derivatives with two or three monosaccharide units connected together by acetal or ketal linkages. 

The terms oligosaccharide and “polysaccharide” are used to describe larger aggregates having “a few” or “many” monosaccharide units. In modern usage, the distinction between few and many appears to be drawn at about 10 units.

Structure of Monosaccharides

Monosaccharides are carbohydrates which cannot be further digested to produce simpler polyhydroxy aldehyde or ketone molecules. Aldose is an aldehyde-containing monosaccharide, whereas ketose is a keto-containing monosaccharide.

 C6H12O6 is the chemical formula for glucose. Glucose is a significant source of energy in humans. During cellular respiration, energy is released from glucose and used to help build adenosine triphosphate (ATP). Plants employ carbon dioxide and water to create glucose, which is then used to meet the plant’s energy requirements. Excess glucose is typically retained in the form of starch, which is later catabolized (the breakdown of larger molecules by cells) by humans and other animals who consume plants.

Other prevalent monosaccharides include galactose and fructose, which are found in milk sugars and fruit sugars, respectively.

Disaccharides

Disaccharides usually release two molecules of same monosaccharide or two molecules of different monosaccharides after hydrolysis.

When a water molecule is lost, an oxide bond is produced between two monosaccharide units, and this linkage is refereed as glycosidic linkage.

Lactose, sucrose and maltose are examples of common disaccharides. Lactose is a disaccharide which is made up of galactose and glucose monomers. Milk contains it naturally. 

Maltose, often known as malt sugar, is a disaccharide that results from the dehydration of two glucose molecules. 

Polysaccharide

A polysaccharide is a long chain of monosaccharides with glycosidic linkages connecting them. The monosaccharide chain can either be branched or unbranched, and it can comprise a wide range of monosaccharides. The molecular weight can range from 100,000 Daltons to more than 100,000 Daltons, depending on how many monomers are connected. Starch, cellulose, glycogen, and chitin are examples of polysaccharides.

Starch is a combination of amylose and amylopectin that is used to store carbohydrates in plants (both polymers of glucose). Plants can manufacture glucose, and any glucose that is produced more than the plant’s immediate energy requirements is stored as starch in various plant components, particularly roots and seeds. The starch in the seeds feeds the embryo as it develops and can also be used as a food source for people and animals. Humans absorb starch, which is broken down into smaller molecules like maltose and glucose by enzymes such as salivary amylases. The glucose can subsequently be absorbed by the cells.

Cellulose is the most common natural biopolymer. The cell walls of plants are mostly made of cellulose, which acts as structural support for the cell. Wood and paper are examples of cellulosic materials that are abundant in nature.

Structure of Cellulose

Physical Properties Carbohydrates

Carbohydrates are a diverse group of macromolecules with a wide range of physical characteristics. 

1. At room temperature, glucose, for instance, is a crystalline white powder. Its melting point is between 153 and 156 degrees Celsius. 

2. Starch is a complex carbohydrate that is made up of several glucose molecules linked together. 

3. The melting point of starch is 256 – 258 degrees Celsius as a result of its greater complexity.

4. Starch is a white crystalline powder at room temperature.

Elements

Carbon, hydrogen, and oxygen make up carbohydrate molecules. A minimum of one oxygen atom is linked to each carbon atom. A hydroxyl group and ketone group or an aldehyde are found in every carbohydrate. Carbohydrates can be found in long, straight or branched chains. However, regardless of the final structure, all the complex carbohydrates are made up of individual units known as single sugars or monosaccharides.

Conclusion

Carbohydrates are a class of macromolecules that provide structural support and energy to fungi, plant cells, and all arthropods, such as lobsters, shrimp, crabs, insects, and spiders. Depending on the amounts of monomers in the molecule, carbohydrates are classed as monosaccharides, disaccharides, or polysaccharides. Glycosidic linkages join monosaccharides, forming disaccharides as well as polysaccharides with the loss of a water molecule for each bond formed. Monosaccharides comprise glucose, galactose, and fructose, whereas disaccharides include maltose, lactose, and sucrose. Polysaccharides such as starch and glycogen are the storage forms of glucose in animals and plants and respectively. Branched or unbranched polysaccharide chains can be found.