Introduction to Carbohydrates

Carbohydrates are the macromolecules found abundantly on the surface of the Earth. CO2, H2O, and glucose are the main components of these gases. In terms of nutrition, carbohydrates play a crucial role, and they may be found in a wide variety of natural and processed meals alike. When present in living organisms, they serve a variety of tasks ranging from producing energy to contributing to the creation of structures to serving as cellular receptors and adhesions. However, carbohydrates perform a variety of other vital roles in storing energy. Carbohydrates are chemical components in living tissues and foods in starch, cellulose, and sugars. Carbohydrates have the same oxygen to hydrogen ratio as water, which is 2:1.

Carbohydrates Overview

Carbohydrates are biochemical molecules made up of carbon, hydrogen, and oxygen in a ratio of one carbon atom (C) to one water molecule (H2O). Carbohydrates are made up of carbon (carbo-) and water(-hydrate), and their name comes from this combination.

Carbohydrates are classified as simple or complex types:

• Simple Carbohydrates

 Simple carbohydrates are found in soft drinks, cookies, and other sweet treats. These foods commonly include white sugar, a processed sugar.

Simple carbohydrates include natural sugars. They originate from fruit, sugar, and anything else sweet. These substances can be easily broken down by the human body, which causes various issues.

• Complex Carbohydrates

Complex carbohydrates are a vital source of energy for your body’s operations. They supply your body with the long-term energy required for exercise, daily activities, and even relaxation and recovery.

Complex carbohydrates are frequently composed of single units (monosaccharides) chemically linked together. The oligosaccharides range from two to ten simple sugar units in their composition. Polysaccharides are made up of hundreds or thousands of monosaccharides connected. Complex carbohydrates provide energy that lasts for a lengthy period.

It is possible to classify carbohydrates into distinct categories based on their behaviour when subjected to hydrolysis. They are primarily divided into four types of groups:

1. Monosaccharides
2. Disaccharides
3. Oligosaccharides
4. Polysaccharides

Carbohydrates Formula

Carbohydrates are massive macromolecules made up of carbon (C), hydrogen (H), and oxygen (O), and they have the general formula Cx(H2O)y. Carbohydrates have the generic formula Cx(H2O)y. They are composed of the same quantities of hydrogen and oxygen as in water. Some carbohydrates do not adhere to the formula Cx(H2O)y, for example, 2-deoxyribose C5H10O4, which does not conform to the formula. However, most of them are represented by the formula Cx(H2O)y.

Characteristics of Carbohydrates

Carbohydrates have the following characteristics: 

• They serve as energy reserves and also store fuels and metabolic intermediates.
• The sugars ribose and deoxyribose serve as the structural framework for genetic material such as RNA and DNA, essential for life.
• Polysaccharides, such as cellulose, serve as structural components in the cell walls of bacteria and plants, respectively.
• Glucose and lipids are connected to carbohydrates, and these proteins and lipids play critical functions in cell contact.
• Carbohydrates’ chemical components are aldehyde or a ketone with many hydroxyl groups.

Monosaccharide

• The term “monosaccharides” is derived from the Greek words “mono”, which means “single”, and “saccharide”, which means “sugar.”
• Monosaccharides are polyhydroxy aldehydes or ketones that cannot be further hydrolysed to simple sugar.
• Monosaccharides are simple sugars.
• They dissolve in water as they are crystalline.
• Monosaccharides have the formula (CH2O) and usually have three to seven carbon atoms.

• Most of the oxygen atoms in monosaccharides are in hydroxyl (OH) groups, but one is in a carbonyl (C = O) group. The carbonyl (C = 0) group position can be used to classify sugars:
  • When the carbonyl group is an aldehyde, the monosaccharide type is referred to as an aldose.
  • When the carbonyl group is a ketone, the monosaccharide type is referred to as ketose.

Examples of Monosaccharides: glucose, fructose, galactose

Disaccharide

• Disaccharides are two sugars or monosaccharides linked together by an O-glycosidic bond.
• Disaccharides are simple sugars that are soluble in water.
• The glycosidic bond is produced due to condensation (i.e., eliminating a water molecule).
• Disaccharides can be hydrolysed even further by disaccharidases found in the digestive tract.
• Disaccharides are classified into two functionally distinct groups:
  • Reducing Sugars 
  • Non- Reducing Sugars

Examples of Disaccharides: Sucrose, Lactose, Maltose

Oligosaccharide

• It is composed of 3–10 monosaccharide units in a saccharide polymer.
• They are most commonly found as glycans, lipid- or amino acid-chain-compatible polysaccharides connected by N- or O-glycosidic linkages within proteins.
• Cell adhesion and recognition are two of the most important activities of oligosaccharides.

Examples of Oligosaccharides: Raffinose

Polysaccharide

• A polysaccharide is a lengthy chain of monosaccharides connected by glycosidic linkages (poly- Meaning “many”).
• The chain may be branched or unbranched, and it may comprise various forms of monosaccharides.
• A polysaccharide’s molecular weight can reach 100,000 daltons or more if enough monomers are linked together.
• Polysaccharides are polymerised carbohydrates that include hundreds or thousands of carbohydrate units.
• Polysaccharides do not reduce sugars because the anomeric carbons are linked together by glycosidic connections, preventing them from reducing.
• Polysaccharide is divided into two types:
  • Homoplysaccharides: A homopolysaccharide is a polysaccharide made up of only one type of monosaccharide unit (e.g., glucose).
  • Heteropolysaccharides: The term “heteropolysaccharides” refers to a polysaccharide that contains more than one kind of monosaccharide unit.

Examples of Polysaccharides: Cellulose, Starch, Glycogen

Overview of Carbohydrate Metabolism

Overview of Carbohydrate metabolism involves catabolism and anabolism.

Glycogenolysis is the breakdown of glycogen into glucose. Glucose, our cell’s main energy source, is oxidised to ATP molecules during cellular respiration. Non-carbohydrate sources of glucose include lipids and amino acids. This is called gluconeogenesis, and it occurs when the body has too much glucose.

Conclusion

Biochemically, carbohydrates play an essential role in the functioning of the organism. Carbohydrates are the primary source of energy for the human body. A wide variety of carbohydrate options are available. Various carbohydrate types can be formed by combining one or more sugars. As the primary component of starch, a complex carbohydrate is made from hundreds of recursive sugar units.