Modern genetics study mainly depends on the knowledge of chemical and physical features of DNA. DNA has 4 basic components that are known as nucleotides and some of the most common properties of DNA emerged from these 4 basic components of DNA.
Nucleotide polymer is nothing else but it is building block of DNA. It is also known as polynucleotide. Every nucleotide has 3 components in it – phosphate group, 5 carbon sugar and nitrogen containing base.
The atoms of sugar carbon are numbered in between 1 to 5, and at point 1 nitrogenous bases get attached and the 5th point is the place for the attachment of phosphate group. Every nucleotide forms DNA polymers, by connecting themselves with the phosphate group of 1 nucleotide to the 3rd carbon of the other nucleotide. Backbone of the molecule is nothing else but it is the continuously repeating pattern of sugar, phosphate and then again the phosphate.
The term deoxyribose here refers to the sugar in DNA. And this deoxyribose differs from ribose (ribose is found in RNA) in which 2nd carbon lacks a hydroxyl group. Deoxyribose lacks a hydroxyl group hence the prefix deoxy is used. The hydroxyl group which is missing in the deoxyribose plays a very important role in the 3-D structure and the stability (chemical) of the DNA polymers.
Nucleotides of DNA has 4 different types of nitrogenous bases i.e. thymine, adenine, cytosine, and guanine. They form 2 groups:
Purines – Adenine and guanine both have double ring that is made up of 5 atom ring which gets attached to one side to the other ring which has 6 atom ring.
Pyrimidine – Thymine and cytosine; both of them have a single chain that has 6 members in it.
The genetic information which is carried out by the DNA is encoded by the order of nucleotides along with DNA polymers. The length of DNA polymers is tens of millions of nucleotides. These 4 nucleotides in such a big length carry unlimited information.
Nucleotides are also same in structure but they do not have phosphate group in them. In the absence of this phosphate, group nucleosides are not able to form chains. Facts about nucleotides:
- These are the building blocks of DNA and RNA.
- Single units of nucleotides (monomers) forms polymer by connecting to each other.
- These nucleotides contain genetic information in DNA.
- In cell metabolism, each and every nucleotide play a very important role.