All the materials needed for you to grow, all the cells, all the essential fluids like haemoglobin, white blood cells etc are all manufactured by your DNA, inherited from your parents.

All the vital functions performed by your body, such as thinking, excreting, hunger, digestion, performed by precious vital organs, all this starts from your genes, your chromosomes, your DNA.

So what is your DNA?

It is a type of nucleic acid that has four different chemical groups, called bases: adenine(A), guanine(G), cytosine(C), and thymine(T).

It has the shape of a twisted ladder.

It is the genetic origin of every human being. And it contains all the information needed to sustain a person throughout that persons life span.

#Continuity of life >DNA replication

DNA of various organisms have two major ways of replication, we will be mentioning the two, but looking at one today (the one in man) .

• Semi-conservative method; used by man and

• Rolling cycle method; used by viruses and bacteriophages.

Semi-conservative method:

In this method ,the old strand to be duplicated is called a DNA template,we also have a small fragment of DNA called primer, is placed near each old DNA.
Then an enzyme called DNA polymerase enzyme, goes round bringing floating bases and joining them to the primer in a complementary fashion to the old DNA (also called template).
Hydrogen bonds are formed between the bases to hold the strands together.

And that's how new DNA is formed. As the replication continues, the uppermost strands continuously unwind, thus:making the partially completed replication process look like a "tuning fork". Thus the name replication fork in Semi-conservative DNA replication process.

Two copies of DNA are produced, each containing 1 old strand and 1 new strand.
And so we have Semi-conservative DNA replication method.

Note:

Three consecutive bases on the DNA is called a CODON.
Each CODON codes for a specific amino acid, which when joined together in chains form proteins that eventually form so many tissues if the body, and organs and so on, and so forth.

So now you see how organs are produced and maintained in your body, day in, day out. And all starts from the tiny molecules of DNA in your body.