October 30, 2017 Monday
Bedtime Story
Archaea - Our Most Ancient Cousins
As I keep saying, most of even very
prominent scientists die generally as unknown figures.
In fact, it can be almost guaranteed that
if I were to ask you to name any living contemporary scientist in any field,
may it be astrophysics or mathematics or molecular biology or microbiology or
even any field of your choice you or your memory would be very hard pressed to
recall a name.
To recall any microbiologist would be
perhaps next to impossible for microbiology after all is one of the driest of
all the subjects, especially for medical students.
I still recall how we would dread to
memorize the names of various pathological microbes and their culture characteristics,
culture in this case not very different from the way we would define culture for
human apes.
Yet even I as a medical student never
recall having been taught about a group of organisms called Archaea.
Till date I had never come across Haloferax
and Haloarcula, single celled organisms with just glycerol-ether lipids for
cell membrane, a circular chromosome with no nucleus or any membrane bound
organelle?
Amoeba yes, but Haloferax and Haloarcula…No
way!
Their metabolism is quite strange and
varied, some using sunlight, some using energy trapped in inorganic chemical
bonds and some using organic compounds to obtain energy.
Even those that use sunlight are not
obligatory photosynthetic, but have devised mechanisms of electron transport
chains or direct proton pumping to establish electro-chemical gradient.
This is all that the enzyme ATP synthase
needs to provide molecular energy currency for these archaic cells.
Worse of all they never have sex and are
total celibate!
They are so primitive that they have been
around here since the birth of life and hence we apes gave them the heading of
archaea which in Greek means “ancient things”.
It has to be stressed that archaea are
distinct from bacteria and that they are no more related to each other than
each is related to eukaryotes.
All these three groups shared ancestral
colony of organisms but they later on diverged in three different ways.
Much before cells evolved some 3.8 billion
years ago when there existed just the replicator molecules, lateral gene
transfer was very convenient and almost unrestricted, and Darwinian natural selection was unable to
exist its pressure.
It meant that even an “unlucky” replicator
molecule would get to share the benefits of a “lucky” replicator and thus
genetic advantage was pooled.
But such free lateral transfer of gene
probably allowed fixation of certain subsets of genes.
This would become important later when the
basic lipid membrane formed around the replicating molecules, isolating the
lucky from the unlucky replicators.
Formation of this lipid barrier around the
replicators is called the Darwinian transition by the evolutionary biologists.
Stay tuned to the voice of an average story storytelling
chimpanzee or login at http://panarrans.blogspot.com
Good night mon ami and my fellow cousin ape.
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Another great educator and a teacher that I am aware of is
Professor Subhashish Chattopadhyay in Bangalore, India.
While I narrate stories, Professor Subhashish an electronic
engineer and a former professor at BARC, does and teaches real mathematics and
physics.
He started the participation of Indian students at the
International Physics Olympiad.
Do visit him here:
All his books can be downloaded for free through this link:
For edutainment and English education of your children, I
recommend this large collection of Halloween Songs for Kids:
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