The Overview of Biomolecules:
The molecules which are produced by living animals are known as biomolecules this includes large Macromolecules like protein, lipids, polysaccharides, and nucleic acids and small molecules like metabolites , and natural products. These molecules are also known as biogenic substances.
The biomolecules are basically divided into two types small molecules and polymers. Small molecules are lipids, glycolipids, polysaccharides, sterols, glycerolipids, vitamins, metabolites and neurotransmitters, hormones. The most important biomolecule is nucleosides and nucleotides. The DNA is made up of these nucleotides. Nucleoside are molecules which are formed by attachment of Nucleobase to ribose or deoxyribose ring. These are cytidine, uridine, adenosine, thymidine , Guanosine, thymidine and inosine. The enzymes kinases phosphorylate nucleosides within the cell and results in production of nucleotides. DNA and RNA are made up of repeated structural units , monomers of mononucleotides.

The other form of biomolecules are Saccharides. Commonly known as the sugars. Monosaccharides are the simplest form of carbohydrates which contains simple sugar. These contains ketone or aldehyde group in their structure. Aldehyde group presence is known by aldo prefix and ketone group is known by prefix keto. Fructose, glucose, hexose are monosaccharide. When two monosaccharides combine they form disaccharides. Or two single simple sugars formed by bond with removal of water molecules. Lactose, maltose and sucrose are disaccharides.

The complex form of monosaccharides are known as polysaccharides which are polymerized Monosaccharides. They have multiple simple form of sugars. Glycogen, Cellulose and starch are examples of polysaccharides. Oligosaccharides are shorter polysaccharides with 3-10 monomers. The complex polyphenolic macromolecule composed of beta-O4-aryl linkage are known as lignins.
The fatty acid esters are known as Lipids. These are the basic building blocks of biological membranes. Lipids are amphiphilic. Fatty acids consist of unbranched chain of carbon atom connected with single bonds or double bonds and known as saturated fatty acids and unsaturated fatty acids respectively. The lipids which are present in biological membranes with hydrophilic head are of three classes. These are Glycolipids, Phospholipids and Sterol (e.g. Cholesterol).
The molecule which has both carboxylic acid functional group and amino group is known as amino acids. Amino acids are the building blocks of proteins. During protein synthesis only two amino acids other than twenty are known to be involved during translation. These are selenocysteine and Pyrrolysine.

Proteins are known as particular series of amino acids and attached by linear polypeptide backbone. There are different types of proteins. They are globular or filamentous proteins. Many enzymes are proteins. But it does not mean all proteins are enzymes. Many a time's statements are made in study and are asked to justify. It is "All enzymes are proteins but all proteins are not enzymes" The difference in type is related with their form or structures. The hydrogen bond is either alpha helix or beta sheet. The secondary structure of protein is known by their number arrangement. Thus when two or more number of polypeptide chains clusters, they form protein. This is known as quaternary structure of protein. Hemoglobin is protein which has two alpha and two beta polypeptide chains. Hemoglobin are integral part of blood and this is very important in oxygen transport though out the body.Vitamins are not synthesized by a given organism. Coenzyme is one such example but it is very vital for the survival or health. Vitamins are vital amines. Another biomolecule is Apoenzyme which is a protein but without cofactors, substrates or inhibitor bound to it. It is inactive form of storage, transport or secretary form of protein. When cofactor is added to Apoenzyme , it becomes activated enzymes. Inorganic Cofactors are metals ions, iron sulfur cluster and organic cofactors are flavin and heme.

Isoenzymes or isozymes are multiple form of enzyme. They have slightly different protein sequence but usually not identical functions. It has been found in research that different genes are responsible for its production.

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