Glycolysis
[Intro]
Hey sugar
Come on over here, sweetie
Let's break it down

[Verse 1]
Glycolysis is a series of reactions, enzymatic actions, energy transactions
Takes glucose, a molecule so sugary
Breaks it down for NADH and ATP

It's an anaerobic cytoplasmic pathway that amazes
Organized easily into three phases:
Investment, cleavage, and energy harvest
Tell me later which one you like the best

Investment: activation energy's supplied
Cleavage: our six carbon sugar divides
Harvest: we get our energy yield
So beautiful, so intricate, keep your eyes peeled!

[Chorus]
Glycolysis, come on sugar, come on sugar
For the breakdown, for the breakdown
[Verse 2]
Investment's like striking a match
That energy you put into it makes the fire catch
For glycolysis, investment's two ATPs which act as activation energy

Enzymes take phosphate from ATPs
Jam 'em onto glucose, rearranging it to fructose
Leaving fructose 1,6-bisphosphate on the table
With two phosphates, it's highly unstable!

Moving us to the second phase
The cleaving of fructose bisphosphate
'Cause glycolysis means "splitting sugar," you can see
Cleavage yields two molecules with carbons three

One is glyceraldehyde 3-phosphate, G3P
It continues on our pathway, broken down for energy
But the second one an enzyme will immediately
Convert into a second G3P

[Chorus]

[Verse 3]
Phase 3: G3P gets rearranged and oxidized
By an enzymatic assembly line
That harvests energy from each G3P
One NADH and two ATPs
Double this yield per G3P
To two NADH and four ATPs
That's the gross yield for every glucose in
A generous accounting of glycolysis' win

But two ATPs were invested in phase one
So you net just two you can use to jump or run!
Put two in, get four out, your net gain is two
Two ATPs that you can use

If that doesn't seem like very much, it's 'cause it ain't
There's tons of energy left in pyruvate
The two 3-carbon molecules we're left with at the end
And what happens to pyruvate's gonna depend

On the metabolic pathway where pyruvate gets sent
If it's anaerobic, it'll be fermented
But in aerobic cells, pyruvate's termination
Will be the Krebs cycle and total oxidation

[Chorus]

[Verse 4]
Glycolysis starts with investment
Of two ATPs to the glucose that we started with
The product is cleaved into two G3Ps
From which the cell harvests NADH and ATPs
This anaerobic pathway is respiration's first phase
Billions of years old, evolved in ancient days
Before O2 accumulated in the seas
Before eukaryotic cells arrived at the scene

It's everywhere, ubiquitous, in every organism
Bacteria, sequoia tree, no matter your metabolism
Happens in the cytoplasm, doesn't need no organelles
You want to find glycolysis? Look in any cell!

[Chorus x2]