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DNA
• In very basics• All the life programs are primarily stored in
DNA• For example : why cow is different from you,
because it has different DNA than you . and why banana is different than you ,
because it has different DNA than you
• Basically in a fertilized ovum , all the genetic material which is present , have the complete program to make structurally and functionally complete organism
and all that programming is in the molecule of DNA
RNA
• DNA expresses it self in the form of RNA • The functional copies of DNA are RNA• You can say master plan is in DNA , and the
master plan makes a functional copies which is the RNA
• And from the RNA we make proteins
So how the system works
• In particular cell , DNA will express certain RNA ‘s , and RNA will make particular type of proteins , and those proteins will determine the structure of a cell as well as the function of a cell
Definition of DNA
• DNA is un branched linear polymer of nucleotides .
• For example : in this picture , lets say these are un branched linear , polymer of nucleotides
• So as the picture is shown DNA contains nucleotides , this means to understand how the DNA is made , actually u must understand how nucleotides are made
• To make a molecule of DNA, first of all we must have a nitrogenous bases
what are nitrogenous bases ?• Nitrogenous bases are nitrogen containing
carbon rings
• there are two types of nitrogenous bases 1= double ring structure which are called
( purines ) 2= single ring structure which are called
( pyrimidines )
-purines ( double ring structure ) contains 1= Adenine 2= guanine- pyrimidines ( single ring structure ) contains 1=cytosine 2=thymine
• Nitrogenous bases alone can not make DNA , so they are fused with sugar , when sugar contains 5 carbons and oxygen , they are called (pentoses) .
• In carbon position number 2 and carbon position number 3 , if they are hydroxyls this sugar is called (ribose sugar ) .
In ribose sugar , if you remove the oxygen from carbon position number 2 and leave only
hydrogen , then this sugar is called ( dioxyribose sugar )
• If in a nucleic acid (nucleic acid is DNA and RNA) with dioxyribose sugar is used then that nucleic acid is going to be DNA
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