Central Dogma Zen
(To the tune of "Those Were the Days")
Copyright 2008 Indira Rajagopal and Kevin Ahern

Once upon a time a cell decided
The time was ripe for it to split in two
Had to copy cellular instructions
For the daughter cell would need them too.

Bring in a helicase
Unzip the DNAs
To ease the stress a gyrase joins the fray
Strands must be held apart
SSBs do their part
And primase builds a primer RNA.

Sliding clamp comes in behind clamp loader
dNTPs floating all around
In the wings a replicase is waiting
For the chance to start another round.

Polymerase, my friend
Starts at the 3’ end
It puts a T across from every A
A G across from C
Perfect simplicity
The leading strand is made in just this way.

The lagging strand is made in little pieces
Okazaki fragments, you recall
Pol I fills the gaps that lie between them
Ligase comes in next and joins them all.

Blueprints can’t have mistakes
That’s why polymerase
Corrects its work
With exonuclease
Proofreading one by one
Till all its work is done
Hurray for D-N-A polymerase!

An organism's cellular construction
With blueprints for the things they have to do
Requires converting DNA instructions
To ribopolymers, oh yes it's true

Because they've been bestowed
With a genetic code
The RNAs provide the cell with means
To link amino A's
In most directed ways
Inside the protein-making cell machines

If "coli" cells don't have galactosidase
And lactose should appear inside its food
The lac repressor leaves the operator
'Cause otherwise metabolism's screwed

Polymerase unwinds
The DNAs it binds
Adjacent to the start site where it docks
Unravels A's and T's
With such amazing ease
At the promoter's little TATA box

The process moves along without much trouble
While making RNA inside the cell
It all occurs inside transcription bubbles
Where bases get linked anti-parallel

mRNA then roams
To find some ribosomes
Subunits large and small bind near the end
The A-U-G's in place
Inside the P site space
Initiation you can comprehend

The mechanism shifts to elongation
Proceeding by three bases at a stretch
A GTP's required for translocation
Advancing 5 to 3 the whole complex

The process moves anon
Until a stop codon
Arrives and causes movement to suspend
Translation has to cease
A peptide gets released
And we have reached the central dogma's end.

Back to Kevin Ahern's Metabolic Melodies