What are carbohydrates? Classify and give detail of each class along with examples.

What are carbohydrates? Classify and give detail of each class along with examples.

Written By Khansa Yousaf

Carbohydrates are organic compounds that consist of only carbon, hydrogen, and oxygen. Saccharide, another name of carbohydrates, is derived from Greek word Sakkron which means sugar. Their empirical formula is Cm(H₂O)n where m can be different from n. They are found in a large variety of food like cereals, honey, milk, potato, sugar beet, dates, pasta and sugarcane. They provide most of the energy that keeps the human engine running. Besides, carbohydrates are a rich source of energy in many plants and animals.

Classification of carbohydrates:

They are classified into simple carbohydrates and complex carbohydrates.

Simple Carbohydrates: Simple carbohydrates are monosaccharides and oligosaccharides. 

  • Monosaccharides: 

Monosaccharides are the simplest sugars, which cannot be hydrolyzed. Their general formula is Cn(H₂O)n. They are further subdivided into trioses, tetroses, pentoses, hexoses, heptoses etc. 

Examples of Monosaccharides:

  • Glucose: 

Glucose, the fundamental unit of carbohydrates, is an immediate source of energy for cellular respiration and blood sugar. Naturally, it is found in blood and urine of animals, honey, and sweet fruit, especially ripe grapes and mangoes.  

  • Galactose:

It is a sugar produced by mammals and is found in milk and yogurt.

  • Fructose:

Fructose is found in honey.

  • Oligosaccharides:

They are compound sugars. On hydrolysis, they yield two to ten molecules of the same or different monosaccharides. Depending upon the number of monosaccharides yielded on hydrolysis, oligosaccharides are classified into disaccharides, trisaccharides, tetrasaccharides and so on. The general formula of a disaccharide is Cn(H₂O)n-1. Common examples of disaccharides are sucrose, lactose, and maltose.  

  • Sucrose: 

It is one of the most common disaccharides, which is found in table sugar. On hydrolysis, it gives glucose and fructose.

  • Lactose: 

Another important disaccharide is lactose which is found in milk. 

  • Maltose: 

It is a product of starch digestion. Maltose and lactose are also known as milk sugar.

  • Complex carbohydrates: 

Polysaccharides are complex carbohydrates.

  • Polysaccharides:

Polysaccharides are complex sugars that yield more than ten molecules of monosaccharides on hydrolysis. Their general formula is (C₆H₁₀O₅)n. They are further classified into homo-polysaccharides and hetero-polysaccharides.  

  • Homo polysaccharides:

They are made up of monosaccharides of the same type. Examples of homo polysaccharides are starch, glycogen, cellulose, and pectin. 

  • Hetero polysaccharides

They consist of molecules of different types of monosaccharides. Examples are Hyaluronic acid and Chondroitin.


Miss Khansa Yousaf is one of the bonafide students of Sir Syed Kazim Ali. She has completed her 5 month-course on Online Creative English Writing and Advanced Grammar under his patronage. Having done graduation in science and courses in creative English writing, she loves writing blogs and articles about science and life.

Name of the Student: Miss Khansa Yousaf
Qualifications: B.Sc. (Physics, Maths)
Total Articles/Blogs: 2
English Coach: Sir Syed Kazim Ali
Course Taken: Creative English Writing & Article Writing

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