➕ H2O ➖

The water molecule is a little under 300 trillionths of a metre across.
2x Hydrogen + 1x Oxygen...

H2O. Why are these atoms life-giving?

2x2 electrons bind to complete each outer electron shell. Electron shells like to be 'complete'.

Oxygen’s got more +ve protons in its nucleus than Hydrogen.
So Oxygen’s got more pull over those shared -ve electrons.

The ‘O’ end is more -ve.
The ‘H’ ends more +ve.
A polar bond.

So... why should a +ve / -ve molecule be life-giving?

+ve attracts -ve

Water forms strong bonds with other water molecules. Hydrogen bonds.
Hydrogen bonds that are 10x stronger than the usual forces between molecules.

That’s why.

And that’s why water has...

⬆ surface tension => that insects can run across.
⬆ melting + boiling point => ice + cups of tea. Say no more :)
⬆ surface tension + capillary action => that all plant life relies on.

Water molecules LIKE to bond to each other.

And like a very big, unsociable group of friends, water pushes ‘outsider’ molecules into as little space as possible.

That's a good thing...

Proteins fold into complicated shapes that can do things.
Phospholipid membranes form well-organised sheets + compartments.

The Phospholipid detail (feel free to skip)

Phospholipid has a +ve phosphate head + 2x dangling carbon-hydrogen legs.

+ve heads like water.
The dangling legs very much do not.
So... the dangling legs hide. Naturally...

+ve heads face outward towards the polar water.
The legs sandwich together in the middle of 2x layers.
Like soldiers sleeping shoulder to shoulder, feet to feet.

...as far as the microscopic eye can see.

Proteins dot the sheet to form a membrane.
Membranes wrap up to form compartments.

The protein dots are tiny doors that sort and separate.
Controlling what goes in, and what goes out.

Proteins and charged particles where they should be.
Like a self-organising wardrobe with tiny doors.

Elongated nerve cells...

...stretch out their membranes
From our brain to our spinal cord.
And from our spinal cord out to our muscles.

Metre long membranes that balance +ve sodium and +ve potassium ions.
Sodium mainly outside, and potassium mainly inside the cell.
Inside remains -ve.

Until...

A +ve charge lands.

BANG! Membrane proteins shape shift.
+ve sodium ions rush in.

An electrical spark explodes.
The cell’s -ve charge flips... momentarily.

Passing that +ve charge like a relay baton...
...further down the nerve cell.

BANG! Membrane proteins shape shift.
+ve sodium ions rush in.

You get the picture.

The electricity of life sparks... cascading down the nerve cell.
Sparks race along. 100 metres per second.

Sparks of information.

Information from our ears, eyes and muscle sensors.
Into our brain. Onto our motor cortex.
Motor cortex to muscle.

Muscle pulls.

Nerve, nerve, nerve, muscle, bone, joint, ball, racket… BOOM!
Andy Murray wins Wimbledon.

Or we stay balanced upright and don't fall over.