4.1 BIOLOGICAL MOLECULE || Part 2 || IGCSE BIOLOGY ||

Is DNA a new storage tape?  To unveil the truth, you 
should know the Basics of DNA. I hope you all know about the cell. cell 
is the basic unit of all living organism.   cell contain nucleus inside the 
nucleus you have chromosome. For example in a human cell 
there are 46 chromosomes   or 23 pairs of chromosome these chromosomes 
are visible under light microscope. when you unwind the chromosome the structure of 
DNA is visible DNA is a short form of Deoxyribo   Nucleic Acid. The nucleic acid that is the genetic 
material which determine the makeup of all cells   the short segment of DNA is called gene. Gene contains exons and introns. exons can code 
for protein introns or non-coding sequences   a complete set of DNA in a 
cell is called as Genome. Let's discuss about the structure of DNA. DNA 
is otherwise called as Deoxyribo Nucleic Acid.   if you look at the ribose sugar you can see 
five carbon atoms because it is a pentose sugar   in the second carbon atom the hydroxyl 
group is replaced by the hydrogen group when nitrogenous base is 
attached to the ribose sugar   it forms nucleoside when the phosphate group is 
attached with nucleoside it forms nucleotide.

Nitrogenous base can be grouped 
into purines and pyrimidine. Remember! this mnemonics "pure age". so purine contains Adenine and guanine. purine always binds with the pyrimidine.  purine has a fused structure it is a combination 
of 5 and 6 membered heterocyclic compound.  pyrimidine has 6 membered ring so usually 
in RNA (uracil is found instead of thymine) so Guanine binds with cytosine especially 
in DNA you can see that triple bonds in   Guanine and cytosine thymine binds with 
adenine where you can see double bond. Adenine binds with thymine sometimes instead 
of thymine there will be a uracil component. what is meant by base pair? Two dna base or nuclear base that are 
complementary to one another are called basepair. As you know the basic idea of DNA. 
Let's proceed to our question,   How much data does DNA store in a haploid genome?  That is 23 chromosomes 
contain 32 billion base pairs. In a diploid genome double the haploid base 
pairs which means 64 billion base pair.

now one nuclear base has two bits. To calculate the total genome 
multiply the diploid genome by 2 bits   we get 128 billion bits or we can 
also call that as 1.5 gigabytes. Our DNA can store 1.5 gigabytes of information..

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