Lactose Verse

(nerdy science verse)

I marvel at E. coli
As everybody knows
It has a way of managing
Its many sugar woes

When it does not see lactose
Its operon’s not expressed
Because the lac repressor
Keeps everything repressed

But when lactose appears in cells
A good researcher finds
The lac repressor snatches it
No DNA it binds

Then RNA polymerase
Sees open operator
But doesn’t really do too much
Until the need is greater

This happens when the cell has got
No other energy
And then it starts to make a lot
Of cyclic AMP

Which binds transcription factor and
The DNA it wraps
I think you might have heard of them
The proteins known as CAPs

When this occurs, a CAP binds to
It’s cleverly named CAP site
And RNA polymerase
Makes RNA all night