A Short Note On Carbohydrates

Human bodies can be conceived of as a processing facility for chemicals in many respects. Chemicals are ingested, treated through various processes, and then transported throughout the body for immediate use or storage. The chemicals that the body processes can be classified into two categories: macronutrients, which are substances we ingest daily in large amounts, and micronutrients, which are compounds that we only require in tiny amounts. Carbohydrates, lipids, and proteins are the three major macronutrient types required by living organisms. In this article, let’s discuss the first macronutrient, i.e. carbohydrates, in detail.

What Are Carbohydrates?

These naturally occurring organic compounds are a vital energy source for all living organisms. In chemical terms, they are optically active polyhydroxy aldehydes or ketones. The general formula to represent carbohydrates is CX (H2O)Y. They consist of carbon, hydrogen, and oxygen.

Classification Of Carbohydrates

Carbohydrates can be broadly segregated into Simple Carbohydrates and Complex Carbohydrates.

Simple Carbohydrates

Units of sugar make up all carbs (also called saccharide units). Simple sugars are carbohydrate molecules containing only one sugar unit (monosaccharides) or two sugar units (disaccharides). Simple sugars taste sweet and are readily broken down in the human body to provide energy. Glucose and fructose are two of the most abundant monosaccharides.

Monosaccharides

• Monosaccharides are the most basic carbohydrates since they can’t be broken into smaller carbs.
• Chemically, they are aldehydes or ketones with multiple hydroxyl groups.
• They are significant as building blocks for nucleic acid production as well as fuel molecules, as in glycolysis. Monosaccharides are present in the cytosol most of the time (cell sap).
• The number of carbon atoms, the position of the carbonyl group, and the chiral feature are all used to classify monosaccharides.
• An aldose is a monosaccharide with an aldehyde carbonyl group. A ketose is a monosaccharide with a ketone carbonyl group.
• Trioses are monosaccharides made up of three carbon atoms. Tetroses are made up of four carbon atoms. Pentoses are made up of five carbon atoms, while hexoses are made up of six carbon atoms, and so on.
• Glucose and fructose are the most common monosaccharides found in fruits and vegetables. Xylose, mannose, galactose, and arabinose are examples of minor monosaccharides. Arabinoses and xyloses are the most typically found pentoses.
• Some fruits and vegetables, such as corn, sweet potatoes, and peas, have a high concentration of monosaccharides.

Disaccharides

• Often referred to as a double sugar, a disaccharide is a molecule made up of two monosaccharides (simple sugars) joined together. They are made up of 12 carbon atoms and have the chemical formula C12H22O11
• Disaccharides are created when one water molecule is eliminated from each monosaccharide in a dehydration reaction.
• Sucrose, maltose, and lactose are three prevalent disaccharides. Lactulose, trehalose, and cellobiose are some of the less frequent disaccharides.

Oligosaccharides

• Hydrolysis of oligosaccharides yields three to ten molecules of monosaccharides sugars.
• The monosaccharides in oligosaccharides are linked together by o- glycosidic bonds.
• Examples are stachyose and raffinose.

Complex Carbohydrates

Complex carbohydrates are derived from simple sugars. To put it another way, complex carbohydrates are long chains of connected simple sugar units (for this reason, complex carbohydrates are often called polysaccharides). The complex carbohydrate starch is extensively found in potatoes. Starch is a polymer of glucose, a monosaccharide.

Plants employ starch as the primary carbohydrate to store glucose for subsequent usage as energy. Starch is commonly stored in seeds as well as other specialised organs by plants. A few significant starch sources include rice, wheat, potatoes, corn, etc.

When humans consume carbohydrates, an enzyme called amylase, found in saliva, and the intestines, breaks the links between the glucose units. It thereby allows the sugar to enter the bloodstream. Once it has been absorbed into the bloodstream, the glucose is sent to the locations where energy is needed. It can also be saved in the form of glycogen in the muscles and liver.

Functions Of Carbohydrates

Carbohydrates in food serve several essential purposes in the human body. They are energy generation, energy storage, macromolecule synthesis, sparing protein breakdown, etc.

Energy generation

Several cells prefer glucose to other substances like fatty acids as a source of energy. Glucose is the only biological energy source for specific cells, including red blood cells. About 70% of the glucose that enters the body through digestion is redirected back into the bloodstream by the liver for utilisation by other tissues. The chemical linkages between the carbon atoms provide the energy that comes from glucose molecules.

Sparing protein breakdown

When there isn’t enough glucose to fulfil the body’s needs, amino acids are used to generate glucose. This process necessitates the degradation of proteins, mainly from muscle tissue, since amino acids do not have any storage molecules. So, the presence of sufficient glucose prevents protein breakdown in the body.

Macromolecule synthesis

Even though most ingested glucose is turned into energy, part of it is converted to deoxyribose and ribose, which are vital building blocks for macromolecules like RNA, ATP, and DNA. Glucose is also used to generate NADPH molecules, which are vital for oxidative stress prevention and are involved in various other chemical activities in the body.

Energy storage

Carbs can also be stored in plants and animals in the form of starch and glycogen, respectively. This stored glucose helps provide a strong structure to the plants and helps the seeds grow. In animals, the stored glycogen acts as a source of instant energy.

Conclusion

Carbohydrates are one of the major categories of biomolecules. They are the most prevalent organic substance in nature. They serve various purposes, including acting as a kind of energy storage in the body. They also function as cell membrane elements that facilitate some kinds of intercellular communication. Carbohydrates are also a structural element of many species, including bacteria’s cell walls, insects’ exoskeletons, and plants’ fibre cellulose. The above article concerns the classifications and functions of carbs in detail.