Carbohydrates are not necessarily polymers--long chains of molecules, they can be made of a single monomer as seen in glucose. However, their empirical formula is Cm(H2O)n, with the ratio of H to O atoms 2:1. The role of carbohydrates is to store energy as in polysaccharides like starch and glycogen, to be a structural component as in chitin in arthropod shells, or cellulose in plant cell walls. Carbohydrates like glucose provide immediate energy to use in respiration. Proteins are composed of one or more polypeptide chains. These are composed of amino acids held together by peptide bonds. The building block of proteins, or amino acids, contain an amino group, a caboxyl group and a side chain, all bonded to a carbon. It is this side chain that produces one of 20 different amino acids in nature. Proteins are part of the cell membrane. They are important catalysts known as enzymes which allow chemical reactions to proceed at body temperature in an accelerated manner. Some are important cell signaling molecules, for example, insulin from the pancreas cells directs the storage of glucose as glycogen in liver and muscle cells. Some act as receptors to bind to a signaling molecule, resulting in a response inside the cell. Lipids are made of fatty acids and glycerol. They include fats, waxes, oils, sterols, fat-soluble vitamins A,D, E, K. Lipids store energy, are part of the cell membrane and are signaling molecules. Lipids are important components around neurons in the brain, that allow nerve cells to be insulated and allow for the proper transmission of impulses. All three substances, carbohydrates, proteins and lipids are organic compounds, as they contain the elements carbon and hydrogen.
Example : Glucose, Starch, Cellulose and many more
Carbohydrates are polymers which are made up of number of sugar monomers like glucose, bonded via glycosidic bonds. These glycosidic bonds can undergo hydrolysis via enzymes. For example, amylase hydrolyse starch and cellulase hydrolyse cellulose.
The main function of carbohydrates is as energy source of mayn living beings and it is the main energy source of humans.
Example: Enzymes and some other bilogically active molecules in nature. Haemoglobin is a good example.
Due to the molecular bonding withing the amino acid sequence proteins automatically fold into a structure of their own. This makes the activity of that protein more specific and efficient.
Enzymes, which are proteins act as biological catalysts in a lot of reactions. In starch hydrolysis, amylase act as the catalyst.
Fatty acids. They are usually found in natural oils like coconut oils. Some fatty acids are oleic acid, palmitoleic acid and myristoleic acid.
Due to their long hydrocarbon chains and carboxylic acid group, they exihibit both hydrophobic and hydrophillic properties. This property is widely involved in making cell membranes in nature.
Lipids are involved in cell membranes, especially phopolipids. Also fats are used as a long term energy storage in humans and other animals.