Look at what’s coming out of the nucleus
Destined for a ribosome, a strand of mRNA
It’s got the code, the information,
For the protein we’ll be making today

The RNA message is organized
Into codons, that’s a sequence of bases three
That spell out one and only one amino acid
A genetic code that works universally

A codon has its match in an anti-codon
Three bases on a tRNAs bottom side
tRNA’s job is to bring amino acids
To ribosomes so proteins can be synthesized

mRNA, tRNA and ribosomes
plus amino acids make a protein making machine
Read the codon, make a polypeptide
That’s translation – cells synthesizing proteins

The small subunit of a ribosome binds
With that mRNA’s leading end
And slides until it reaches start codon AUG
Indicating where translation begins

A ribosome has three binding sites
Where tRNAs can bind
The “A” site’s first, “P”s next, then “E”
And the E’s got an exit sign

The first tRNA in this translation process
Binds the start codon in binding site “P”
And that tRNA carries an amino acid
That goes by the name of Methionine.

And now to finish this initiation
The ribosome needs to be made complete
The large subunit binds the small subunit
Now we’re ready for translation to proceed.


Now we’re ready for next step: elongation
An amino acid carried by a new tRNA
With an anticodon matching with the second codon
Binds at the site called “A”

Then the ribosome carries out an enzymatic action.
Binding these amino acids with a peptide bond
So a dipeptide hangs on the “A” site tRNA
Watch translation move along!

Next the ribosome shifts exactly one codon over
In a move that we call “translocation”
So the “A” site’s empty, and the “P” site’s loaded
And the first tRNA’s in the “E” location

“E” site tRNA makes its exit
And the next tRNA fills the site called “A
And the ribosome catalyzes away
In your cells it happens every second, every day

And watch that polypeptide, see it get longer
As each and every codon get translated
Ribosomal robots reading RNA instructions
As proteins get created!

Protein synthesis!
(repeat 4X)

We started with initiation, which was followed
By part two of translation: elongation
Now it’s time to finish synthesizing this protein,
With a finale called termination.

When the ribosome gets to a stop codon
There’s no tRNA anti-codon that matches
So “A” site’s bound by a release factor:
The polypeptide detaches

tRNAs at P and E sites float away
Ribosome breaks apart, no longer one
The polypeptide folds into functional protein
Translation is done!