MODULE 17

• Carbohydrates are macronutrients and are one of the three main ways by which our body obtains its energy.
• They are called carbohydrates as they comprise carbon, hydrogen, and oxygen at their chemical level.
• Carbohydrates are essential nutrients which include sugars, fibers and starches.
• Carbohydrates are found in grains, vegetables, fruits and in milk and other dairy products.
• The food containing carbohydrates are converted into glucose or blood sugar during the process of digestion by the digestive system.
• Our body utilizes the sugar as a source of energy for the cells, organs, and tissues.
• The extra amount of energy or sugar is stored in our muscles and liver for further requirement.
• The term 'carbohydrate' is derived from a French term 'hydrate de carbone' meaning 'hydrate of carbon'.
• The general formula of this class of organif compounds is Cn(H2O)n.
• The carbohydrates are further classified into simple and complex which is mainly based on their chemical structure and degree of polymerization.
• Monosaccharides and disaccharides are the types of simple carbohydrates.
• Simple carbohydrates have one or two sugar molecules.
• In simple carbohydrates, molecules are digested and converted quickly resulting in a rise in the blood sugar levels.
• Simple carbohydrates are abundantly found in milk products, beer, fruits, refined sugars, candies, and etc.
• Simple carbohydrates are called empty calories, as they do not possess fiber, vitamins, and minerals.
• Plants, being producers, synthesize glucose (C6H12O6) using raw materials like carbon dioxide and water in the presence of sunlight. This process of photosynthesis converts solar energy to chemical energy.
• Consumers feed on plants and harvest energy stored in the bonds of the compounds synthesized by plants.
• Monosaccharides' one example is glucose, glucose is an example of a carbohydrate monomer.
• Other examples of monosaccharides include mannose, galactose, fructose, etc.
• Monosaccharides may be further classified depending on the number of carbon atoms:

  • (i) Trioses (C3H6O3): These have three carbon atoms per molecule
  • (ii) Tetroses (C4H6O4): These monosaccharides have four carbon atoms per molecule
• Disaccharides are formed when two monosaccharides are combined.
• Examples of carbohydrates having two monomers include: Sucrose, Lactose, Maltose, etc.
• Lactose= Glucose + Galactose
• Sucrose= Glucose + Fructose
• Complex carbohydrates have two or more sugar molecules; hence they are referred to as starchy foods.
• In complex carbohydrates, molecules are digested and converted slowly compared to simple carbohydrates.
• Complex carbohydrates are abundantly found in lentils, beans, peanuts, potatoes, peas, corn, whole-grain bread, cereals, etc.
• Polysaccharides are complex carbohydrates formed by the polymerization of a large number of monomers.
• Examples of polysaccharides include starch, glycogen, cellulose, etc. which exhibit extensive branching and are homopolymers - made up of only glucose units.
• Starch is composed of two components - amylose and amylopectin.
• Amylose forms the linear chain and amylopectin is a much-branded chain.
• Glycogen is called animal starch.
• Glycogen has a similar structure to starch, but has more extensive branching.
• Cellulose is a structural carbohydrate and is the main structural component of the plant cell wall.
• Cellulose is a fibrous polysaccharide with high tensile strength.
• In contrast to starch and glycogen, cellulose forms a linear polymer.
• The main function of carbohydrates is to provide energy and food to the body and to the nervous system.
• Carbohydrates are known as one of the basic components of food, including sugars, starch, and fibre which are abundantly found in grains, fruits, and milk products.
• Carbohydrates are also known as starch, simple sugars, complex carbohydrates and so on.
• Carbohydrates is also involved in fat metabolism and prevents ketosis.