DNA molecule
If asked, what is life or who
are you, we generally reply philosophically, without even caring or respecting
the fact that whatever we are is a result of a very long process, which is
initiated by a smallest macro molecule you can imagine! We are what our DNA is,
what every single information on that DNA.
We all know what a DNA is, at
some point in our life we’ve heard of DNA and basically have idea of what it
does. But ever wondered how it does, whatever it does? DNA has, something
called Base pairs, also known as building blocks of DNA. There are four types
of base pairs, Adenine (A), Guanine (G),
Cytosine (C), and Thymine (T). What DNA actually does it, in simple words,
transfers these base pairs so that they can form amino acids. And how does that
take place?
It’s called
the Central Dogma, which describes the molecular flow of genetic information. DNA
has all the genetic information, the blue prints. So let’s call our DNA, an
Engineer who knows what and how to make it! But, the engineer doesn’t go to the
field and make the structure himself. He just directs the worker to do it, he
never leaves his office. Why? You may ask, well in this case, if the DNA leaves
its home, which we called Nucleus, it might as well get damaged because of
various chemicals that are present the cytoplasm which is the outside of
Nucleus! So he sends the message to an RNA, his worker so that the RNA will
carry it to the outside, but again RNA doesn’t do the work, he is just the
messenger, so again he translates our engineer’s message to amino acids, which
are our builders and finally when they receive the message they build whatever
they are asked to build, since they’ve received the blue prints from the
engineer.
What does
the blue print have?
Well, as
I’ve mention before, what DNA has is base pairs, A T G C and since I just
mentioned them and didn’t explain what they do. So here’s the part where they
come. When we say, DNA is the blue print, what we mean is DNA has codes,
Genetic Code, the codes are in the form of base pairs, ATGC and what our
Engineer does is, transcribes those codes to RNA, while doing so replacing T or
Thymine with Uracil, because instead of T from DNA, RNA has U, or Uracil. So,
if DNA sends the code as ATG, it becomes AUG in RNA, and when RNA translates it
to code for methionine which is an amino acid. Amino acids are building blocks
of proteins!! So in this way various
amino acids are coded and in the end proteins are formed in Ribosomes in
accordance with the Central Dogma!!
This is what it looks like!
What if the
Codes are lost in the between?
Well, when
Engineer sends for the his worker to take the blue print to the builders,
sometimes, on the road, he might lose some files, data’s or sometimes something
written with pencil could be erased. Then, what happens is the code is changed
and if the Blue print said, The door should be facing north, it might now face
south.
For eg. AUG
codes for Methionine, but if the G is replaced by another A then it will code
for the Amino acid Isoleucine.
Lets say the
code was AUGA in a sequence of AUGAAUCGGCA etc.. but the base that was coded was AUG, and the
3rd one the G is deleted on its way and A comes after U. So, the
code which was meant to code for Methionine ends up coding for Isoleucine.
Methionine
is a sulfur-containing essential amino acid that plays a crucial role in
metabolism and growth, where as function of
isoleucine is
proteinogenesis in the body,
which means it is a building block for the proteins your body cells make. So metabolic part is
hampered and such events are termed as Mutation.
So, if
you’re reading this and you don’t have much problem then you’re perfect because
if you weren’t then you’d not be here right now! Because there are 3 billion
base pairs in humans and even if one of them went missing or deleted or replaced
then you might have some trouble, at times major, so consider yourself lucky!
And, that is
how DNA works, now moving on to rest of the part.
How is DNA
transferred from one person to another? Well I shouldn’t go into much detail of
that should I ? haha!
But anyways,
another important thing is, Chromosome, we always heard that as well right?
And, that we have 23 pairs or 46 chromosomes. In every part of our body, the
cell division results in formation of same number of chromosome. But in case of
sex cells, the number is reduced to 23! Why?
Because the
next set of 23 comes from your partner!
So, here’s a
recap!
The 46
chromosome that you have came from you parents! 23 from your father, 23 from
your mother! You were made up of 46 Chromosomes. And your sperms are made up of
only 23, and when they fuse with your partner’s ova, which again has 23, your
offspring or for the time being, Zygote again has 46!!
Lets get
into detail, you have 46 chromosome, now they have to be 23, but how are they
selected? I mean which 23 out of 46 goes into your sperm?
Lets say,
there are 23 volumes of Book in a Library, a book called Chromosomes, with 23
volumes of it! There are two books for each volume, one black another brown. Lets
say that book volume no. 12 has the blue print for making an eye! Volume 12 A
makes Black eye and Volume 12 B has blue print for Green eyes! So, there’s a
fight between those books, to decide which gets to be on top, in this case,
with our normal frequency the black one wins, because green is a recessive
character. In this way the 23 chromosomes are selected out of 46 which can be
divided into two 23-23 chromosomes coding for the same thing! And if, one of
the volume is lost, you’re in trouble and if one volume is added more, or there
are 24 volumes in display, you have Down’s syndrome! Haha! See how important
your life is?
Now, to the
final part! The sperm with blue print, with 23 pairs of chromosomes which has
the base pair sequence or blue prints travels or swims to reach the ova! Fuses to
for the Egg! And then when the Sperm fertilizes the eggs, it becomes the zygote
and it starts to divide into various cells and organs!
Btw another
interesting thing is that, the formation of various organs work as per
induction, i.e. presence of one tissue influences the development of others.
Eg,
If the
ureteric bud fails to arise from the mesonephric duct the metanephros will not
be induced to form a kidney, and such complication results in death and if not
death, abnormal conditions which will cause big problem once born! And this is
just one example! There are thousands of such complications! And if you don’t
have any, you are perfect, you’ve gone through such a complicated process and
everything was perfect, with out perfection you’d not be here!
This is just
a brief explanation and if I were to get down to all of it, it would make a
book! Just the brief one has almost got me to my 7th page haha!
Anyways life
is complex important process and fucking important! Don’t waste it!
